 to start the afternoon session of our meeting. Leonardo, are you with us? Yes, I'm here. Hi, Leonardo and hi, colleagues. I think that's Stefania, right? Yeah, yes. Hi, nice to meet you. So let me have a look at the participants. Maybe we give them like two minutes more to connect because it's two o'clock now. So we give them a few more minutes and then we start. Excellent. Lucrecia, I wanted to ask you something. So can we share the presentation from our computer because we made some small adjustments? Sure, sure. The only thing I would like to ask you afterwards is to please send us the updated presentation. We will upload it on the web page. Okay. Okay, thank you. So two more minutes and then we start. Okay, I think we can start. So dear participants, now we have a very interesting session on equipment installation, use and maintenance. So good practices given by Mrs. Stefania Perez Fernandez, Mrs. Jessica Loryberg and Mr. Leonardo Ramirez Lopez from Buki Labor Technique, Switzerland. So Leonardo, colleagues, the floor is yours. Thank you very much, Lucrecia. So can you allow me to share my screen, please? How's disabled participants screen sharing? Yeah. Yeah, you should be able to share it now. Yeah. So does everyone see my screen now? Yes. Yes. And see your screen. Excellent. Yeah. First of all, thank you very much for inviting us to, to this meeting and also to, to present these, these, our experiences basically with the equipment installation, the use and the maintenance of say, general laboratory devices. Once. Okay. So. Today with me is Stefania Fernandez Perez as Lucrecia already mentioned. Just, I give you a little bit of a little bit of a little bit of a little bit of a little bit of a little bit of a little bit of a little bit of a little bit of a little bit of a little bit of a little bit of a little bit of a little bit of a little bit of a little bit of a little bit of a little bit of a little bit of a little bit of a little bit a little bit of a little bit. So I, I give you a little bit of introduction to myself. I'm a soil scientist by training. Um, I have been working basically with with, in soil science over the past 15 years. Um, my, my core expertise is in the NIR spectroscopy. Hi, I am Stefania Perez and I'm a biologist by training but through my PhD I got into the NIR world as well and so my specialty is NIR Chemometrics and I have also worked and applied this technique to soil analysis. So we're basically specialized in NIR mainly but yeah with ample experience on applications for this. Yeah so as I said our core expertise is in the NIR infrared spectroscopy devices or infrared spectroscopy devices although here within the company we have also gained some experience with other type of devices and also with the general installation of devices for different types of laboratories around the globe. So we have well the company has a quite wide experience is present in different countries around the world as I said which I think that it is really important to gain experience about the good practices when it comes to the installation of instruments. We interact on a daily basis with a lot of users and we have noticed that there are some let's say common pitfalls that we believe that are really easy to account for but if they are not really correct or if they are not really that account for they have they might have a really big impact in the results or in the quality of the results that your laboratory delivers. So we have the company here we built a lot of different devices and yeah they will be they are listed here in the in the presentation and also some devices that are really relevant to the soil laboratory analysis are listed here although we said we were thinking with Estefania okay how do we where to focus for this presentation we thought that we should focus on those complex devices so for example atomic absorption spectroscopy which is not really which is yeah which is let's say really a common device in soil in soil laboratories. We are not going to focus on those tiny devices like the potentiometers because I think that that the the the manuals in the manuals we can we can easily see how they operate how to how to maintain them and those are not really complex we have the devices that we are going to talk about today are listed here the nitrogen determination by Kielder analysis the elemental analyzer for carbon and nitrogen and potentially sulfur atomic absorption spectrometer which is which as I said is really important for determination or like assessing nutrients in the soil and of course NIR spectroscopy and infrared spectroscopy in general we know that those are not really like typical devices in in soil labs but we see that in the near feature those devices will be present or will be really useful in in laboratories okay not not to perhaps not to replace current technology or standard technology but they will be present there to support the analysis or the analytical the standard analytical methods and we will see that later in the in the in the upcoming slides. Okay so with those with those devices what do we cover then so if we talk about Kielder then we mean basically nitrogen total nitrogen in soils if we talk about atomic absorption spectrometer then we we are covering basically exchange exchangeable bases and also exchangeable acidity manganese iron as well and other elements that we will see later so when we talk about dumas or elemental analyzers then we talk about carbon mainly also nitrogen and in some cases sulfur and finally when we talk about NIR spectroscopy or NIR spectrometers we we talk about carbon the analysis of carbon the termination of or the prediction of nitrogen the exchangeable bases the the ph the the texture of the soil and with mid-infrared spectrometers we can basically they assess again exchangeable bases exchangeable acidity carbon nitrogen ph and a very wide range of of properties so before we jump directly into the devices themselves we wanted to give you some like very very basic recommendations that we think that they apply to all devices okay for installation especially so the first one let's say the first rule I will say is that the equipment should be always be installed by a specialist from the company you purchase the instrument okay so you you have if you if you buy an atomic absorption spectrometer you are definitely entitled to ask for an specialist to come to your laboratory and install it okay so if any of your equipment is used in a manner not specified by the manufacturer then the protection provided by the by the manufacturer might be might be impaired so that's why I say that it is really important that a specialist from the company comes to your place and do the installation so that basically you are let's say carefree about the about about damages in the instrument or breaking the the warranty and and so on and also the advantage of having a specialist from the company or from from the provider is that he will be able to answer all your questions when you for the first time uh let's say open and operate the the the instrument so you get the kind of um customized training for yourself so take advantage of that okay and the other thing that is also really important is that try not to leave the instruments there lying in your lap for a for a long period of time I think that if you buy an instrument today then try to start using it or try to install it as soon as possible because the the the earliest then the the the the easier it will be for you to get support from the company you purchase where you are going to to get the instrument another important thing is that um yeah we have seen that it's better when the when the when the when the users they ask in advance for a list of what they need to have I mean what are the requirements that they need to the for prior to the installation so where they need if you need computers you need to you need to purchase them in advance the power plugs for example that sounds like a ridiculous to think about power plugs but this is really important to take into account sometimes the installation of an instrument may be a block by just a simple power plug because perhaps the laboratory is not in a the laboratory is in a very remote place and it is difficult to get the proper plug so please ask the the the checklist from the provider of the instruments so that you make sure that everything will run smoothly during the installation and also check about the environment the environment that you need to install your um for which you need to install the uh in which you need or to install the the device sometimes um i'll condition in systems are required in in those rooms where you are planning to to install the instrument so check for all those kind of things and i think that the best the best way to to get a proper list is not do it by yourself but ask the the provider okay um another thing that is also important is when when when when you um get the instrument when you get it installed then you can also ask the the specialist to get to create that kind of uh with you a routine maintenance schedule with a list of check uh tasks that uh for each device that you have or what for the device that perhaps um if you plan if you plan to do all the maintenance by yourself is highly recommended to attend training courses provided by the device supplier when the instruments are really complex the the supplier they usually they offer training so please try to attend those trainings or perhaps now now we discord on a viral situation webinars have become more available so check the the the websites of the of the of the suppliers for webinars so that you can basically get proper training for operating your instrument peripherals i think that it is also really important this is in hand with what i said before with the checklist of what you need um um for the installation of the instrument so make sure that all the peripherals that you are going to get for the installation are actually compatible with the instrument that you are going to receive so another thing that sounds like obvious is that um the on off buttons must be always in the off position before the connect before connecting to the power supply always always especially in those cases where the where the power the the the electricity is not so so stable so those are kind of the the basic rules for the that we can identify that are common to let's say all of the complex instruments so now i um i want to give the the the the here the the microphone to westefania she's going to talk about kieldan for nitrogen determination hi everyone um yeah so kieldan is one of these main techniques that we decided would be relevant to talk about and we all know that nitrogen determination is quite relevant so um let me see yeah i'll start explaining briefly the the process um the keldal process consists of um three main steps the the the procedure is um it's like like a mineralization of organic material in in boiling mixture of sulfuric acid and sulfate salts at boiling temperatures for 120 degrees celsius there is a digestion process in which the organically bonded nitrogen is converted into ammonium sulfate the next step would be the alkalinization and distillation uh during this step the the ammonia is liberated and then is steamed distilled uh and ready for the next step which would be a titration to determine to finally determine the the amount of nitrogen in in the in the final solution um this is a classical setup for for kieldan uh where we have the flask uh where the digestion occurs uh then we have um another flask uh where the alkalinization and distillation happens and the final stage for titration um thankfully there are automated systems for kieldan analysis which allow uh the sampling of up to 20 samples so the previously was one by one now it's a an automated system um here i'm showing um one of the devices manufactured by the company just because i have the pictures but this would be the same for for any any device um we have several units for each of these steps first we have the the digestion unit in which the up to 20 samples are digested we we see here on the left side this blue part this is called a scrubber this is is quite important because during the digestion toxic fumes are produced so this uh this device the scrubber uh collects and neutralizes these toxic fumes uh the second unit is the auto sampler it actually goes together with the with the with the other unit the alkalinization and distillation but the auto sampler basically uh contains the sample tubes as i said up to 20 and automatically uh like with a mechanic arm it samples each tube and transfers the solutions to the to the alkalinization and distillation units um the third in the third unit again alkalinization and distillation happens and finally uh we have the titration unit with red etc ph well the titration could be colorometric or potentiometric usually is potentiometric and well yeah we also have a touch pad but this of course depends on on each device it's no mandatory i guess um i have here a slide in which i i leave you a link in case you want to see this process in in in action uh it's a youtube video i mean it's accessible to anyone of course i've been talking about sulfuric acid and like strong chemicals so this is a the nature of this process makes really important that we talk about health and safety and i have listed here like the main health and safety aspects i think that have to be taken into account are like the high temperatures for example this digestion happens at a really high temperature toxic fumes produced by digestion uh so they use some manipulation of acid and basic reagents which can cause skin burns you could drop the tubes the glass broken glass can you know it can happen it's unlikely but electricity it's also a risk we should take into account of course so of course good practices i mean this is applicable to any laboratory really but i think it's necessary always to remember to wear protective goggles gloves lab coats and the instruments are heavy the the units are heavy so it's always recommended that um that you lift them with the help of someone else um talking about the installation it's also necessary that we take into account these health and safety measures so for example i was talking about toxic fumes so it's quite important that you place the device in a fume hood for for the extraction of these gases um you need to have a stable clean level surface clear also not have a lot of stuff around or containers or other chemicals that could flame because of the high temperatures um so yeah and also well this is obvious but you have to make sure that you have the main switches and plugs and taps and everything you need accessible at all times and not have interference of cables here and there uh also the the setup is is important for the for the health and safety and for the correct operation of of the device uh the for example the digestion unit doesn't need to be placed next to the autosampler and the alkaline station units but uh but the digestion unit should always be next to the scrubber because the scrubber will be more efficient at extracting the the fumes from the digestion uh then for example the the autosampler should be next to the distillation but that's just because the mechanical arm is designed to to work like that but these these are things that also they seem simple but when you receive your device you don't know like how much space do i need should i put this here should be there so it's important to to always know how much space you're gonna require and what you're gonna require for example what connections like electrical connections data connection between the different parts of the system um reagent or water or waste connections it's important to have a storage tank and also level sensors that will tell you when the when the tank is filling up and you need to empty the waste tank etc and of course we we talked about peripheral devices already but not only a computer but also like a balance or a printer or a marker reader you you also need to take into account this kind of thing usually as we recommended already installation should be ideally done by a person like a specialist from the from the vendor company so this should be taken into account by this person however it's good if you in advance are aware of all the all the things you need so so you know that you have the space etc maintenance well maintenance of kieldal devices well it's not so complex i have some general recommendations here and the first one is that the maintenance and repairs should be carried out by trained personnel and also with the with the right tools i guess you can also have like a it's up to everybody but like you could have regular servicing from from the company but if you if you need to do more routine maintenance daily or weekly then it's recommended that you get proper training from the service or a specialist person of the company obvious obvious recommendations well switch off the power supply remove like sources of flammable vapor let the the instrument cool down and this is sometimes this we don't realize but we we don't touch it and it's still hot so and so this is important to to keep in mind and yeah and always wear the protective protective equipment etc that has already been mentioned some maintenance as i was saying so you could maybe do daily or weekly maintenance so you don't need the service person of the company but so what involves the daily maintenance of this device cleaning and calibrating the ph electrode if the if the titration is potentiometric then you you will have a ph probe which you can clean and calibrate using buffer solutions also refilling boric acid for the step between distillation and titration clean the sample sample tubes etc between uses clean like weekly it's recommended that you clean do like a general cleaning like clean the housing clean the titrator the the deep tube of the sampler which is the the tube that goes sample by sample transferring the the solutions into the distillation unit sorry cleaning the colorimetric sensor if the titration is colorimetric monthly monthly you can calibrate the pump and inspect the the smaller bits now like the beret of the titrator the sample tubes again the the amount of distillate every like couple of times a year is is recommended that you check the sealing of tubes and pipes just to prevent any leakage any leaks replacing the splash protector this is something that i forgot to mention but all these units have like a protector a splash protector that prevent all these strong chemicals to to splash onto the user in case there is some leaks or something so sometimes if there is some some splash then the protector could be damaged so you may want to to replace it like a couple of times a year but it's so likely that you will need to replace it so often but and yeah every yeah every six months it's recommended to replace a pH proof and yeah finally yearly if some parts are worn or yeah the pump is damaged or something like this then you may need replacement or for the distillation the steam generator sometimes gets calcified so maybe some of the calcification might be needed every year but I guess it depends on the water hardness of each place so that was like a brief description and some suggestions of killed analysis but um some some lines appear here i'm going over to leo to talk about the elemental analyzers for soil and carbon and nitrogen okay thank you so yeah i'm gonna talk about the elemental analyzers for soil carbon and total carbon and nitrogen total nitrogen as well so we're in the instrument that we uh in the kill that instrument that we saw before we only analyze total carbon with the elemental analyzers we have the possibilities to analyze total carbon and total nitrogen as well as in some cases other elements like um sulfur so the basic basic principle here is that you weight your sample so you have your soil sample you weight this sample then you usually press the sample and in most of the instruments it is recommended that the sample is pressed the your soil sample is pressed and then the instrument what it does like once the sample is there the instrument burns out this sample at very very high temperatures like 1000 degrees around cells 1000 degrees celsius of course with the this is a combustion that is um that is along with the with the oxygen so in some cases this these these temperatures might reach up to 2000 um um degrees celsius so so and then at the end what it what the instrument does once this once the sample is burned so once the sample is burned what it does is that it liberates some gases okay and those gases are captured by the instrument and this is what it is analyzed basically what is inside those gases so how much carbon do we have in there how much nitrogen do we have in there so this is the principle of of operation of those elemental analyzers so and this is a this is an example of or a picture of a a conventional elemental analyzer so here you have the autosampler which is really good i mean usually those instruments they come with um to um with an autosampler that allows you to put around 20 samples 40 samples it depends on the supplier but yeah the autosampler is really really convenient so it comes also of course furnace that is in charge of basically burning out the the sample being analyzed it has some tubes i'm going to explain what is the functionality of those tubes later and how to maintain them and also here you have you see that there is a thermoconductivity sensor um or yeah or detector basically what it does is that it translates that information about the gases so it basically detects some signals about the gases and converts those signals into meaningful information like carbon total carbon and total nitrogen remember that a couple of slides ago i talked about pressing the sample okay so the samples are usually pressed like this so you you take a thin foil and then you you press the sample so that they resemble a pill okay and then those pills are put in the autosampler here so you can analyze as i said up to see in this case up to 60 samples so this is really really convenient if you for the high this is i'm going to explain now with a little bit more detail how much exactly it works so you have i'm going to start from the right and then i will move towards the left of this slide so here we have the autosampler you put your tiny samples there then the samples are transported by a ball bolt and then they go to this ash finger here and oh well in the ash finger of course they are they are burned out then they are they they pass through the post combustion basically which is kind of in charge of burned out the remains of the sample so once you the samples are burned what you get what you try to capture is all the gases that are that are resulting from that burning process so those gases are they come with with moisture i mean with water vapor so what what the system does is that it needs to remove all this water vapor from the from the gas from the from the from the yeah from the gas and those tubes that you see here they are in charge of doing that once the gas basically is free of moisture then the gases pass through the detector okay um okay sorry before before that it goes to the reductor the reductor what it is what is in charge is of doing is that it converts all the the different components containing carbon into co2 and also all the components containing m nitrogen into m2 and once this is done they finally go through the detector to the detection system in this detect in this detection system is basically there you have a sensor that it detects the amount of co2 and the amount of nitrogen in the gas and this is how you can basically um quantify total carbon and total nitrogen um okay so this is a this um this is an odd um um going basically of how it works basically you have the sample it is burned and it goes here then it is dried out then it passes through the reduction process in the reduction in the reduction process what you convert is basically everything that has carbon into co2 and everything what has nitrogen into m2 and then it is um this thermal conductivity the detector is in charge of basically uh measuring what it measures is the thermal conductivity of the gas and then it compares this thermal conductivity of this resulting gas against the thermal conductivity of a gas which can be helium and then based on that basically based on the amount of m2 or or co2 or m2 basically the the the the thermal conductivity varies so you can relate thermal conductivity to the amount of nitrogen that you have in your sample so this is uh what you get basically is something like this at the at the bottom of this slide you see that there is a kind of a spectrum and this is a spectrum of thermal conductivity compared to the thermal conductivity of the um helium and based on that peak that you see there of thermal conductivity you can quantify nitrogen this is really good because it only takes like around four minutes per analysis so and the way in which it is quantified it is basically you put that peak into a mathematical function so basically you compute the area uh the the peak area and relate this peak area to the content of nitrogen or carbon in some of the of the samples that you have if you have um calibration standards you you you can do that job of converting peak area into nitrogen or carbon so as i said the the advantage of this is that it has a really really high throughput basically in nine hours you can analyze around 120 samples because the analysis per sample it takes between four and six minutes so you basically if you can if you prepare all your samples and if you put them all in your in your device then you can leave them running through the night and the next day you come and everything is ready but of course we were talking about really high temperatures like around 1000 degree Celsius so yeah you have to you have to ask yourself basically whether it is a good idea to leave this instrument running through the night if the conditions of your lab um basically you have to ask yourself based on the conditions of your lab i have seen or actually i have i i myself i i have done that already that i have left as samples running overnight with the with this um with this um instrument but um but yeah you have to take into consideration a lot of stuff so that you don't put your lab at risk okay um so it is better if perhaps you analyze the samples in the morning and then while they are being analyzed you do something else so that you can you can keep an eye on that instrument okay and they also on the surroundings of the instrument because the the the surrounding elements um can also get some um heat due to the the the the operational things so um for the installation what you need to consider is it is highly recommended that you have an air-conditioned room as i said again going back to the problem of high temperatures you need to make sure that the that the room the temperature inside the room is always stable so it needs to be dry and very well ventilated um and of course you need to you need to take care of the surroundings so you cannot just place it in a place where where it might get even uh where it can increase the let's say the temperatures so so the carrier gas usually we have to work with helium okay and in some cases it can be also CO2 but in but yeah but basically it depends if you are analyzing on the nitrogen then you can use CO2 as the carrier gas but usually it is highly recommended to use helium with a purity of 99.99 so it has to be really really pure so that you make sure that nothing from that gas that you use as the carrier gas ends up in the in the in your analysis results so yeah pay attention to the supplier of the gas pay attention of the guarantee of the purity of the gas and also for the combustion when you if you use oxygen you have also to pay attention to the purity of the ice the oxygen that you are using you I recommend that you always ask for the guarantee or like like how can I say it's not not the guarantee but but um at least that the the supplier can guarantee somehow that the purity is what it is stated in there in the in the label of the of the of the of the pipes that you are getting reagents so reagents might vary a lot also I I recommend that you check from the instrument vendor or in the manual what reagents you are allowed to use if you are going to deviate a little bit or if you want to change some of those reagents by some hours because it actually for in in in your case make really sense to to use a different type of reagents that are not specified in the in the manual I totally recommend that you go to them to the vendor and ask him hey can we use that reagent yes no and why and perhaps try to come up if if it is not possible try to come up with a with a with a with a workaround or a solution that allows you to basically to do the the the the task that you you were planning to do with those reagents all reagents so calibration standards I think we haven't talked much about that so far but I think that calibration standards are really really important so why because they they are I would say they are responsible of the quality of the results that you deliver as well so try to make sure that the the supplier of those standards is always the same supplier and that the supplier is is that you can guarantee and a supply from of calibration standards from the same supplier over time okay try not to move from one supplier to the other because this might affect also the the the the results that you are getting in your lab so try to keep the calibrations the the the calibration standards supplier as constant as possible okay and again in some cases these these these standards are not supplied by the by the manufacturer so you have to do this task by yourself and call and try to compare different standards perhaps try to call your your your your colleagues in our labs or in our countries and see what kind of standards they are actually they are using so it is also highly recommended that the installation and the first start of the instrument is done by a trained service technician again so because most manufacturers explicitly indicate this as a mandatory requirement otherwise you might lose the guarantee of your instrument so be careful with that because if you lose the warranty then and if the instrument has a problem later six months later or three months later then you will not be entitled to get a proper proper support from the manufacturer and you might incur in like high costs for the maintenance of these elemental analyzers we have to take into account a couple of like let's say a couple of things remember that I show you some tubes and those tubes they have some feelings that they need to be replaced regularly so here for example in the tubes that I'm showing in these slides or in these slides sorry the tubes the pictures of the tubes on the left here they show tubes that are already consumed those tubes are used to dry out the gas basically to remove all the moisture from the gas that you have in your system but you can do this you can you can throw away that feeling and remove and and fill the tubes again with a new feeling okay the feeling needs to be the same as the one specified by the manufacturer so the maintenance of these tubes you have to do it basically around every 800 samples for the drying tube for the small one and around 100 samples for the large tube so you have to constantly really refill those tubes because the samples of course they trap a lot of this moisture and it is really important for your analysis for the quality of your analysis that you keep a really good eye on this and this means so if we are talking about 100 samples or 800 samples and if we are talking also about that the instrument can do around 100 or 120 samples per day if you are doing such amount of samples per day it means that you have to refill these tubes basically every day so pay attention to to that please um the other the other things that you also have to keep an eye are the basically the the combustion tube so where the combustion of the sample happens and also the reduction tube where the separation or basically where where all the carbon and nitrogen are converted into or are put together into CO2 so be careful with those tubes they are usually super hot I mean they it takes takes a while until they are really cooled down so if you have used your instrument and if you are planning to do some maintenance on it right after it is used then take your time leave the instrument cooled down and then do the maintenance but always just for for for safety always where temperature resistance blows so those tubes that I'm showing here in this picture they they they they should be able to last around 1000 samples of use for the combustion tube okay but for the reduction tube and the you need to to look at the the feeling around after after you do around 210 samples for the post combustion tube that is not shown in the picture it also lasts is the one that lasts longer like around 2000 samples so you see with this type of instrument you have to constantly do some some kind of maintenance at least with the tubes um again just try to refill the tubes only with the materials specified by the manufacturer okay um other important checks in here are the leak tests okay and also regular checks on the blank for the blank value determination those are but this is I mean how to do them this is this is specified usually in the manual of the of the instrument and in my body between instrument and instrument so yeah now I will jump into the atomic absorption spectrometers um I like this spectrum I like this type of spectrometers a lot I think that because you can analyze a lot of stuff with this I'm gonna focus today only on the flame atomic absorption spectrometers because I think that they are the ones that are more it's a more common in in laborat in soil labs so when we talk about atomic absorption or AAS spectroscopy we talk about mainly ion exchange or extractable cation determination so if we if we need to to to have a really good uh accurate determination of of um exchangeable bases like like calcium exchangeable calcium exchangeable magnesium potassium and perhaps sodium as well then we need to we we need to consider this type of um of spectrometers um so this means that this type of analysis is really important for um fertility analysis so we can also look at um exchangeable acidity we can also look at um iron and manganese with this instrument uh arsenic selenium and in general heavy metals so we as I said before we can we can we can use this this type of instrument to analyze a very wide range of um of elements in the soil so everything which is highlighted in I don't know what this color is to be honest but everything which is highlighted let's say let's put it this way everything which is highlighted in blue is undetectable and everything which is like red or pink is detectable by the by the by this atomic absorption spectrometer so you see you have a lot of um let's say a lot of possibilities with this type of um spectrometers in your lab so how how does it operate so there there are two let's say two main steps so the first step is the sample preparation that it might be a little bit cumbersome because basically imagine you have a a soil sample what you have to do is to if you want to analyze I don't know exchangeable calcium okay let's just take the example of exchangeable calcium so what you have to do is to take your sample try to extract all the exchangeable calcium from your soil sample you have to do follow some standard operator procedures and then once the the the you have your calcium in a solution then this is the point in which you need to use the atomic absorption spectrometer so if you look at this slide this pink solution imagine that this pink solution is the solution in which you have all the calcium that you want to analyze from that sample we were talking about before so the sample is transported to this mixing chamber okay where you basically mix this fuel gas with an oxidizing gas and then boom that you burn the sample again and then the sample is basically is um it's go it's gone here to the flame to this flame okay and in this flame all these components of the sample are there okay and then you what you do is that you use a lamp to illuminate that flame and based on the composition of the of the atoms in that flame some energy will be absorbed by those atoms and some energy will be the energy that it is not absorbed it will be a transmitted so you have a detector that detects the amount of light transmitted by the sample and then you can if you if you already know about how much how much of the light is transmitted you can infer how much of the light what's absorbed by the sample and based on that absorption you can infer how much and what yeah how much of a specific element you have in that original solution that you presented to the system okay one thing that it is actually worth to mention here is that or let's say one of the one one of the things that makes this um technology a little bit um cumbersome or well not cumbersome is that that this lamp that you see here at the top left corner is a lamp that basically it varies from element to element so if you are analyzing calcium you need to use a lamp that is specifically designed to determine calcium if you are analyzing if you if your goal is to analyze aluminum then you have to have a lamp that it is specifically designed for for aluminum okay but we will go back into that later on in the in the following slides um yeah okay um the flame the flame that you that you produce here is usually produced let's say with uh with a fuel gas and an oxidizing gas as I mentioned before and the the oxidizing gas is so you can okay it operates usually with air nitrous oxide or acetylene so never use any other gas unless it the the manufacturer specifies what else to use okay okay I will go back a little bit to the detector to the detection how it how it works and how it relates to the standards that you have to use as I said before um the what what the detector does is that it captures and conversely uh or let's say tells you about how much um energy or light what's absorbed by the atoms in that flame and the more absorbance the more the the higher the concentration of the element that you are trying to look at is okay the lower the absorbance then the lower the concentration of that of that element and these absorbance happens for every element in a specific wavelength for example if we were talking about calcium before so it means that you have to oh the detector will look at the wavelength to a 422 nanometers of wavelength yeah and then it will look at the it will see that there is a peak like this or a peak like this or like this or like this depending on the amount of calcium that you have in your sample okay and now what is the role that the the the calibration standards place in all this okay so basically what you have to do and I will show that again a little bit later is that um you have to measure um materials or solutions for which you already know and you have a certified value of calcium for example and then you can correlate the absorption to the calcium amount or content and then the system inside it will help you to build a calibration curve and you have to do that for every single component that you have to that you want to analyze and yeah that allows you to also your device to analyze um during the installation it is also really important to look at the at those um houses here so you have to connect your system to another uh to an oxidizing gas you need to also connect it to a uh a supplier of fuel gas and you also have to look at the condensates the hose for the condensates so I'm oxidizing gas and fuel gas so I said before that you can use um nitrous oxide or an acetylene okay um nitrous oxide I think that is really really special basically if you notice if you notice that um you are experiencing some uh euphoric during the during the operation of the euphoria during the operation of the instrument then be careful because this gas this is exactly what it does it cause um uh a feeling of euphoria this is the nitrous oxide is also known as the laughing gas so if you start enjoying too much your um your analysis then be careful with that because this is supposed to be boring so careful with that check those houses and yeah make sure that they are always very very well connected also the condensates this is really important because the condensates can also be a source of explosions um yeah this is basically what I'm saying here in this slide that um they are they need to be correctly blocked especially this one this one is really really important to look at okay so if you plan to do all the maintenance by yourself it is highly recommended to attend training courses provided by the supplier I wanted to to to to bring again or to highlight the attention or to raise awareness of this thing because they have they have been explosions or reports of explosions already in labs due to the to to to the eye here so pay special attention to that here there is a report of an accident that happens in the us with the with this instrument with the atomic absorption instrument and then is um two people resulted um with injuries like severe injuries I'm not gonna talk about this special case but it's just to to highlight the importance of checking the houses going back to the using and so we have we have defined some some some things so we have to consider the burner optimization we have to consider the metal the method parameters this is about the the calibration of your instrument we need to talk about the quality of the calibration standards a proper keeping and the cleanness so let's start with the lamp and burner optimization so all the lamps that I showed you before all the lamp that I show you before you need to optimize the position so because you know we are talking about lamps that emit light and a specific and a very specific wavelength so you need to be careful on how to place those lamps inside the the spectrometer so but you I mean usually in in in the devices they come with software that help you to to align those lamps properly okay it is really important but you have to keep an eye on those as well so whenever you run your instrument make sure that the lamps are called correctly aligned otherwise your detection limits will drop sorry your detection limits will will be kind of messy also for the burner so the the way in which the the the liquid or like the the samples are burned is um it's really important to check okay so going back again to the calibration standard solutions you I said before also that usually those are not provided by the manufacturer you have to look for those standards yourself and make sure that the standards that you get are certified standards and that the provider is is a provider that you can trust that will be able to deliver you to provide you with those standards over a let's say a long period of time so that you can guarantee stability in your lab for those properties that you measure with this atomic absorption spectrometer I also mentioned already that the calibration is done for each element the calibration is basically an equation a very simple equation that converts light absorbance into ion concentration and those equations are usually linear equations that are basically yeah it's just you feed a line and then this equation will be stored in your in your system in your the computer that operates the instrument and will always delivers you the the results of that specific ion you are looking at so your accuracy and precision again depends largely on the quality of the standard so check that standards the quality of them is really important to ensure the quality of what you deliver to the users of your lab in some cases these the the way in which you need to calibrate the instrument is not by using a linear equation as I'm showing here but in some cases you have to look at them or types of equations like a quadratic and so on so when you when you when you calibrate your instrument pay special attention to this okay to to to get a press this this calibration line as accurate and as precise as possible you remember that I said before that the lamp that you use depends on the on the on the on the ion that you are looking at so you have to have a lamp for magnesium you have to have a lamp for calcium you have to have a lamp for potassium so careful with that you have to always I mean usually those spectrometers they they they come with with with the lamps so different lamps that you can place in in a compartment at land compartment so it's not that it comes with one single lamp compartment what for one single lamp you can put play several lamps there and I think that if you are going to to I'd say to acquire an instrument check how many lamps it is you are allowed to put there so that at least you don't have to manipulate those lamps are constantly in your instrument because the more you manipulate the lamps then the the less they will last instruments as I said you usually can allocate multiple lamps ideally your instruments should be able to allocate at least all the lamps for all the elements that you need to measure so each lamp what is special about this lamp so each lamp emits light at the specific wavelengths where the target element absorbs it so if you should calibrate or align the lamps if you have installed a new lamp so if one lamp break and then you need to replace it then you need to recalibrate your your instrument for that specific and element that your lamp was supposed to be used for you need to you need to get the more the best possible signal to noise ratio basically that this guy here this guy here this this signals here they are not noisy but they are very smooth so if you get noise here is because your lamp is not properly aligned or perhaps the burner is not properly aligned but I think that is because of the lamp is not properly aligned so or the lamp can be also dirty sometimes dust keep lying on like accumulating on those lamps so you need to clean these lamps properly sometimes when you take the lamps you you put basically dirt on them so you need to make sure that the lamps are really really clean okay and if you are using a lamp from a different from the one recommended by the right one you also need to use special thanks to the calibration again check your instrument manual for what type of lamp you can use and yeah when manipulating the lamps you need to hold them by the base to avoid dirtiness on them so it is recommended to have spare lamps their lifetime is about between between 1,000 and 8,000 hours again it also depends on the lamp manufacturer so this is not a fixed number but it is good good practice that you keep some spare lamps in your lamp because if one lamp breaks today then it will block all the measurements for that specific element and you never know when you are going to get the lamp replaced so this can be very problematic so keep always a lamp a spare lamp for every for every element in your lamp so when acquiring new lamps check for the lifetime specifications of the provider so some lamps might be cheap and might be might look like a good option but at the end if the if the manufacturer cannot guarantee them a given lifetime then you are is is highly uncertain how much they will last and it will be very difficult for you to plan proper maintenance of your instrument so try to get lamps which at least come with some lifetime specification there are some also some lamps like that some instruments that come from with with sorry some instruments that come with lamps deuterium lamps that are used or those deuterium lamps are basically made out of hydrogen that doesn't absorb that cannot be detected by the absorption atomic spectroscopy but they are used to correct the background effects in the spectrum that you get from the early instruments so check that check those lamps as well because regularly because they last less than the other ones these ones last around 1000 hours so and then it requires also just one single alignment when it is installed on that so again as daily maintenance what you can do is to check for licks this is really important remember that explosion that happens in the US we don't want you to experience the same thing of course check the exhaust system and empty the waste check for the N02 N2O sorry levels and also for the for the CH levels as well and clean the clean spray the chamber of the lamps and all everything which is glass inside your instrument and use distilled water for cleaning always we don't want any interference later on in the measurements coming from dirty water um do a deep cleaning weekly of the spray chamber so spray chambers might vary also a lot across different manufacturers so check the the manual for that and again get proper training check the air filters check the gas supply houses and yeah these those are like the basic basic recommendations of operation of your atomic absorption spectrum as you have as you have seen they are really really useful maybe because you can analyze a lot with them but they also demand a lot from you like a lot of maintenance from you a lot of training let's say to get proper um proper results so yeah now we go into the iR spectroscopy which is again something really really interesting um something that um labs in the futures every lab in the future yeah it's going to to talk about that okay so um let's see can can we delete these lines yeah maybe yeah i'm just afraid because i could see these green lines all the time in the presentation um okay so uh i will talk now about um the use of iR spectroscopy for the simultaneous measurement of physical and or chemical properties of soil um i'm gonna introduce iR spectroscopy uh in general um so basically the technique is based on the interaction of matter and light and it could be in the mid or in the near infrared range these are the two techniques that we thought would be nice to talk about but the introduction is general for both because they're both coming from the same place let's say so um so when the when the light and matter interact the light can be absorbed or reflected by the sample in proportion to its physical and chemical characteristics and the technique is used is useful for for estimating organic compounds mineralogy texture pH there are of course differences between the two techniques but basically the molecules that absorb infrared light or let's say the bonds between atoms that form molecules that form matter or soil um when they are irradiated by infrared light these bonds vibrate and also this causes a change in the dipole momentum that leads to this absorption of light here i show you some moving atoms this would be an example of the movements that happen in in molecules when they are irradiated by infrared light um there are different types of movements you can see one is moving like this the other one is more like a scissors we don't go into that detail but all these things are shown in the infrared spectrum and yeah the um the frequency at which the light is absorbed um corresponds to the natural frequency of the vibration or said in a different and easier way um the frequency at which this vibration occurs is always fixed for types of bonds and types of vibration which helps later on um or which shows as a fingerprint of the molecules in in the sample so in this slide i have a very basic diagram of of an infrared measurement um the infrared devices basically consist of a light source and also means to to select what the wavelength range but let's say it's a light source that hits the sample or soil sample which is in a sample holder and um this absorbance or reflection happens and what is reflected goes into the detector on the right side of the slide we have different ways in which the light interacts with matter for example sometimes there is reflection or there is a diffused reflection which means that the light goes through the sample somehow a bit and then is it's not specularly reflected it's just like more diffusely or more scattered there is absorption in which the light stays in the sample let's say there is transmission where the light goes through the sample there is refraction there is dispersion but really the one that i'm going to be referring to all the talk is reflectance mainly reflection because this is what normally happens with solid samples like soil transmission for example is for liquids so i mean if you have like a sample that you have diluted you can use transmission but normally is reflection that we are using so yeah sorry um this was the way in which light interacts but continuing with the setup basic setup of a spectrometer we have the light source the sample holder the detector the computer which is used to operate the system and also where you can select how you want this measurement to happen also the computer will collect or will represent the IR spectrum which is basically the it's a plot of the absorbance against the wavelength or frequency in which you are operating okay so we have the spectra but the spectra the the spectrum or the spectra uh by by themselves unless you have experience interpreting spectra uh it doesn't tell you much uh especially in nir but we see that later so one of the options you have if you have experience etc is to to interpretation of the spectra which will help you with identification of composition of your soil sample normally what happens is that some chemometrics are involved this means that models predictive models are developed to extract information from the spectra and it's basically it's basically a correlation between spectra uh absorption and reference values okay uh reference values meaning reference that are obtained with a primary technique because IR is secondary technique we still rely on um primary techniques like keldal for example or others to to get for example values of nitrogen the the IR doesn't measure the nitrogen it just measures the spectra and then from the spectra we extract this information by training a model a predictive model that will tell us um these values from unknown samples but we need to always use these calibration models and they are based on reference values that we obtain from primary techniques I don't know if that was very clearly explained but I hope so until now I was talking about IR uh but um we have two adjacent portions of the of the electromagnetic spectrum the mid-infrared and the near-infrared so the mid-infrared is the portion that goes between 2,500 and 25,000 nanometers although normally MIR is referred to in wave numbers a measure of frequency so which would be 4,200 centimeters or wave numbers in the mid-infrared spectrum is where the fundamental vibrations of these functional groups happen what I this what I described basically these vibrations etc this sorry this is what happens in the mid-infrared and this shows as a fingerprint in the spectrum where you can with experience interpret if you know where each component or at which frequency each um functional group absorbs um infrared light and we have the NIR spectrum which is the portion of the of the spectrum that goes between seven 750 approximately to 2,500 nanometers uh but it consists of overtones and combinations of these fundamental vibrations of the of the mid-infrared sorry some people describe it like um the MIR is the drop that falls in the water and then the the waves that are um increasing from that central point those are the NIR bands so whereas the the MIR spectrum looks very defined the the NIR spectrum is really made of broad and overlapping bands so the it's quite complicated to really extract visual information from the NIR spectrum and for these chemometrics or calibration models are needed to extract the information sorry so which one you want to do you do you choose um of course it depends on your needs um the yeah the mid-infrared is the fundamental vibrations and the NIR is a combination bands it's all more overlapping not so clear MIR you see it and what you see there is what you have I mean it's a qualitatively you can get the the information from the first moment but with NIR you can't uh MIR for example proves also really good for soil mineralogy identification um to identify more specific substances just visually um but NIR for example is great for common soil parameters like most of pH carbon nitrogen texture so um here comes some some of the perhaps more critical points like MIR usually requires more sample processing whereas NIR is quite simple dry and sieve the sample to approximately one or two mm and that's it um with MIR it depends on your on your configuration what all the other ways involved the preparation of KDM is really good for soil mineralogy and for soil mineralogy and for soil mineralogy and for soil mineralogy well all the other ways involved the preparation of KVR disks with a special device this is quite time consuming so there are more modern ways nowadays but which are faster but the thing is NIR is more expensive than NIR because the components and the spectrometer inside is uh they're made different so MIR is made of more expensive materials let's say so uh it can be more expensive so it will always depend on which uh are your needs like if you just need the device for general um common routine analysis perhaps with NIR you're fine if you want to study more in detail mineralogy and this kind of thing or pesticides or things like this that you can identify in the spectra and MIR is probably better and also um with uh with MIR if you want to quantify you also need chemometrics anyway so from that point of view there's no advantage in any of the two but yeah MIR is more specific so well briefly I show you here some configurations of NIR spectrometers we have the as we said before we have the light source we have the sample the detector but in between the light source and the sample there is usually an element that will get the light and the wavelengths and we have the old filter based spectrometers which are the simplest but measures only a few determined wavelengths so you are losing information then we have dispersive spectrometers in which we have a dispersive element and then a gap to direct the the sample beam and of course we can see that the the spectra is more complete than the for the filter based spectrometer yeah sorry and well one of these advantages of the dispersive one is the the reproducibility of wavelengths depends on on the mechanical components inside and also there is less intensity in the light and then we have the Fourier transform spectrometers this is the common one for mid infrared and that's why usually mid infrared is referred to as FTIR but also this this configuration is is also possible in NIR devices how it works we have the light source and we have the beam divider it divides the the beam into two beams that go to a fixed mirror and a moving mirror okay then this comes back into the beam divider and goes to the sample the thing is that by the fact that the moving the one of the mirrors is moving and interference happens this is what we call the interferogram okay but this interferogram is then converted into the shape of a normal spectrum with a mathematical transformation it's called Fourier transformation yeah we have I leave you also a link in case you want to see this in more detail the advantage of this configuration is that you get simultaneous information of all the wavelengths at the same time so this reduces the noise and also there is higher spectral resolution and also allows a higher precision of measurements sorry this advantage of this is just that this mechanism makes it all more expensive so these moving parts so this is what I mentioned earlier for example for the NIR because they tend to be Fourier transform so that makes them also it's one of the factors that make them more expensive sorry so that's the basics of what an infrared spectrometer is different configurations but yeah the basic system is this or what you get when you buy a spectrometer is your spectrometer and you also need a computer normally the computers is one of these peripherals that we mentioned earlier that they don't come with the device so to install the the spectrometer is simple connect the the device to the computer through Ethernet cable connect to the to the mains electricity switch on device switch on PC and connect the two of them between sorry connect between device and computer and use the the necessary software that should also be provided with the with the device the good thing about NIR or NIR is that there are no chemicals involved and so you don't really need film cut boards or like protective equipment or personal equipment etc you need to however have of course the proper space and have some surrounding space to place your samples to play with computer etc and I mean common sense just to have a clean stable and horizontal base sometimes you can install the device in a trolley because you need to move it within your lab but in that case just have to make sure that this trolley is stable it's strong and also that there is not a lot of vibration I mean that yeah I guess you're not going to be using it while moving the trolley but yeah just prevent also vibration and again instruments are heavy so make sure that you move it between two people here we come to one of the key issues with with IR devices temperature and humidity affect measurements because especially humidity water is strongly absorbed absorbed by IR so these temperature and humidity variations really affect measurements and here I show you a graph some data collected over years and you can easily see the seasonal variation in some measurements they are measurements of of two peaks two particular peaks and the yellow line indicates where the peak measurement should be and you see that the temperature and humidity that are associated with seasonal changes throughout the year it shows in this picture so this is something really really important to take into account when working with IR devices how is this addressed by installing the devices in a controlled laboratory environment in a laboratory with controlled environment we suggest temperatures between 18 35 degrees humidity should not exceed 30 percent and as I mentioned before if it's possible avoid vibration which could affect the inside moving parts and also keep it clean because dust etc it can get in in the between like them the sampling window and the sample so you would be adding ever to your measurement also for FTIR or mid infrared it's important to have a supply of dust-free protein gas first the system internally to eliminate water and carbon dioxide which cause noise in the spectrum so it would be necessary to have a pipe for the dry air in your lab if you are installing a mid infrared or FTIR device well some additional recommendations something that we have already mentioned follow the manufacturer indications and yeah another detail to mention is that usually the scanning mechanisms are locked from turn rotation so sometimes you install the device and it doesn't work doesn't work but it's just locked you just need to unlock it normally as we suggested you will get the device installed by a specialist of the company so this person should take into account this but yeah we mentioned it anyway because this is something that has happened to us so just to mention it and yeah well apart from installing and connecting to the computer normally is necessary to to carry out some calibration and performance tests before operation now mentioning briefly how to use the devices well again it's a simple simple thing you calibrate the baseline using an external reference it's a reflectance standard I mentioned it a bit later you put your sample this you don't need to do it every measurement like you do that for example at in the morning before you start your routine operation and that should be it then you put your sample in your sample container it could be a petri dish it depends on on the device on the manufacturer etc but yeah recommend we recommend you use the or you follow the user guide I have already mentioned I think that the sample should be previously dried and homogenized to to remove effects of particle size which also affect them the absorption features and and well soil is a very variable matrix so you want to homogenize it as much as possible for this analysis and well once you have your sample in your container collect the spectra just press click and then these measurements tend to take maybe less than a minute half a minute so I guess with your spectra which you can do what I mentioned earlier you can interpret the spectral features using a library or if you have experience enough just visually you can identify components of the sample or you have obtained your estimates estimates thanks to the calibrations that are implemented in the device normally you acquire the device with these calibrations already or you could as well develop them yourselves for which you need to measure spectra and measure using a reference technique whatever property of interest but of the same samples and then yeah the calibration will make a correlation between those two pieces of information and then you develop your model I know I'm not explaining in very much detail but I'm happy to explain in detail at some point if you need anyway once you have collected your spectra and you clean your sample container and then the sampling window of it and then pass on to the next measurement the special ENIR is quite a throughput technique so you can measure many samples in one day up to 100 samples perhaps and the thing is these calibrations you can have calibrations for as many parameters as you want let's say of the I mean of the ones that are possible of course but so whenever you measure a sample and you have your calibrations already in the in the computer you will get estimates instant simultaneously for all these parameters with just one measurement so that's that's a good thing of these techniques that you get a lot of information in just one one measurement so basically you combine all of the other techniques into one so I mentioned like the first step to use devices to measure and calibrate your device with an external reference which are usually I show an image here they are normally made of standard material like PMMA or spectral on they are there are reflectance standards normally they are 90% reflectance so we use these to calibrate the reflectance baseline and frequent measurements of this reference can make compensate for environmental effects and the aging of the internal lamp which could influence the spectrum what was I going to say so the external references are one of our main problems because it's one of the key things that need to be taken into account for maintenance for for these devices and here at the bottom I show a picture of a white reference that we found as a user in a lab and it was completely dirty so of course you cannot calibrate your device the reflectance baseline with a white surface that is dirty so it's really really important to keep the external reference clean and undamaged so I mean recommendations don't drop it don't scratch it don't use cleaning products that are really abrasive or like a sponge or something like this that scratch the surface because this affects the their reflectance yeah I mean some people use compressed air but it's not so recommended because sometimes it's not so clean we recommend that these references are clean with pure acetone and of course don't use them if they are damaged or scratched and yeah the image on the top is very common to touch them with the finger and we have wax and fat in our skin so we leave the fingerprint of our hand and this absorbs infrared light so the surface has to be clean the maintenance of IR devices is also not complicated regularly normally it's automated but you can do it manually carry out the performance tests just to check things like the linearity the wavelength stability the proper work or working of the interferometer the laser etc the signal to noise ratio and of course the the main maintenance you can do to the devices to operate it carefully there are especially in the medium infrared ftr devices there are delicate components for example the the windows are fragile because they are they are made of salts and they are highly hygroscopic so that's one of the reasons why the the environment of the lab should be as dry as possible or if you have spare parts you need to store them in dry conditions and of course you cannot just clean with water because they are salt so you can damage the surface and make it opaque to IR light so of course again follow the manufacturer guidelines but these are things that we have also experienced so that's why we are giving you this recommendation um yeah also yeah cleaning I already mentioned use dry like for the external surfaces use a dry clothes or optical surfaces use optical tissue and the cleaning of the external reference I have already mentioned and of course never open it never open the spectrometer to clean it inside sometimes you can see like a bit of dust there but yeah no don't open it yeah it's also we have already mentioned it's important to always have spare parts in stock things that you could replace in an AR spectrometer something that the the user can do by him or herself is to replace the lamp module the laser unit which is this is only for FT devices filters the lamp desiccant cartridges if there is anything Leo has already mentioned like if you are dealing with lamps you cannot touch the the main surface just take them by by the base as well so really maintenance is is relatively easy and perhaps yearly you want to have your service technician coming to check for for the stability of the like the linearity the wavelength stability etc but I mean these are things that you can check regularly so till here my talk about IR devices we conclude with very brief messages yeah yeah so I was I was looking at them at the questions that we had in the chat a lot of those questions were some of them at least they were related to to specific vendors so yeah in some cases the the operation of the instrument might vary well in basically most of the cases is the operational maintenance of the instruments might vary from vendor to vendor so it's difficult to to have one single unique global recommendation for the operation of one instrument type so therefore please always check the the manuals because this is really important follow the recommendations that are in the manuals and talk about and ask also for proper support from the vendor so is your right so if you buy an instrument which is of course not always cheap you have the right I mean if you have an investment you have the right to ask for proper support so it's not about only buying the instrument and place it in your lab and that's it so I think that is good that you can verify that you can build a kind of a relationship between you and the provider so that you can have proper support because if you buy an instrument and then no support is behind that instrument then if your instrument breaks at some point or you have a problem with that then it would make it unusable in some cases so make sure that you claim your right to get proper proper and and a high level support let's say so this is really important those are basically the recommendations that we have for you today I was also I wanted to say to mention that of course our background as we mentioned at the beginning is not in I mean it's not it's basically NIR spectroscopy infrared spectroscopy and soil science and we are not the experts in perhaps in every detail of the instruments that we show you today but we will be happy to help you with any questions you have regarding those instruments we know people that are really like super experts in in in every of those instruments that we show today so we can come to them ask them for support so that we can answer the questions that that you might have today thank you very much yeah thank you many many thanks Leonardo and Stefania I think it was very useful I'm asking one more to participants if they have any question that has not been answered already maybe there is just one that arrived now about NIR and NIR if they are suitable for analysis of which soil nutrients for fertility evaluation yeah this is a tricky question because yeah it depends a lot on the on the on the type of soil I mean the message that we want to deliver today about the NIR spectrometers is that they don't actually they don't replace one-to-one the conventional soil analysis but we think that this technology can be used to be coupled to the conventional soil analysis to improve the throughput of your conventional analysis so I think that it depends on the in terms of fertility in that it depends on the on the on the properties you are looking at usually when it comes to fertility perhaps it's better to to to use IR spectroscopy if you want to look at the exchangeable cations for example of ions so it is better to use that meet infrared spectroscopy when in my experience I can also say that and for for particle size determination is really good I mean both NIR and IR spectroscopy so you can couple both of them and oh sorry you can use both of them to to help you to to to improve your conventional analysis we also have a question from turkey for c and o analyzer is it necessary to have or sign and annually maintain and service when we obtain good results for calibration standards to check the quality control of the analysis especially from the point of ISO IEC 17 025 standard requirements well I think that is a very broad question I think that if you already have in place in your lab your own quality checks and if you if let's say if you have if your lab is already certified and I think that it is I mean it would be enough from my point of view but this is a very personal point of view I think perhaps someone in the in the in the job might disagree but if that is the case then I don't think that it is really like mandatory that you have to assign a service contract with the with the vendor I mean yeah there is a question from ten being cozy so ten being cozy please unmute yourself and now good afternoon I want to ask if you have the attenuated the reflectance the IR instrument and also if you use the reflectance IR instrument is there a significant difference if you have to use any one of the two I think we couldn't hear you very well but I think what you asked us is that if using an ATR accessory for mid-infrared if there is any difference in using mid or near-infrared is that what you meant the attenuated the more attenuated total reflectance I think in terms of the diffuse in terms of sample preparation you mean you mean I guess in terms of rating the samples for soil parameter yeah you're right using the attenuated total reflectance accessories for the mid-infrared you don't really need more sample processing than for NIR they only I mean you use again you use the dry and milled sample but the normally the sampling window in the ATR accessory is very small so you are reducing a lot the area or the surface that you are sampling in your soil so you are not perhaps capturing so much the variability in that case perhaps you need to do more sub sampling to try and capture more the variability of the soil but but you are right in terms of sample preparation etc is the same as for NIR thank you there are some other two questions for you guys so do you also make a cns analyzers no no we don't manufacture that anymore we in the past we had some in collaboration with a company in germany but we don't manufacture CHMM license at the moment and you have a lot to maybe it was better if you took my offer this morning to start presenting already there are other questions for you so do bucke already have a set of library of organic fertilizer that can estimate the amount of nutrients no we don't no we don't there are there are libraries for pharmaceutical products but we don't have for fertilizers yeah and the other question about mass and particle size for duma combustion I think it's up to one gram that you you can measure with this method in these capsules and I think the particle size is one millimeter I believe but definitely it's just one gram maximum yes which is yeah one of the is one of the things that although duma is quite convenient it's much easier let's say than kieldal that kieldal has a lot more chemicals etc but kieldal allows for higher amounts of sample to be analyzed so again is with more sample you may capture more information than for example kieldal I think is up to 10 grams of sample whereas duma is one gram so yeah you have less less information and it's the same as for the NIR or MIR with this ATR accessory because the sampling window is smaller then you have less representation of your sample I don't know if that answered thank you very much yeah they thank you indeed um well there is a remark I think it's need a good representative of samples for CNS yes okay how is harmonization achieved when instruments vary from vendor to vendor I think that the harmonization is something that also depends a lot on the on the material on the reference materials so as long as you can get for the same for the same reference material the same results then you are in the safe side now so I mean all the instruments as we as we have seen all the instruments they don't directly measure the the the the the the element but they measure is something else that correlates very well with the element so I think that there are many principles of measurements many types of instrument many setups so it's really I mean you will always have this variability is really difficult to to get rid of this variability from vendor to vendor even within vendor you you might have some variability as well so the important thing as I said in as I repeated constantly during the during the presentation is to have a really good set of calibration standards to ensure that your results at the end are really compatible perhaps across different laboratories this is actually one of the main points so we will address through our initiative on spectroscopy so how to harmonize all data and information also coming from different instruments so maybe we can give you a better answer than being cozy in the coming years by working all together because Leonardo and colleagues are also part of the working group on on spectroscopy um maybe we take a last question if you are fine what's the minimum number of samples required in calibrating the near or near against the conventional methods yeah well the point is that it depends as well there is no really like precise answers in this regard but so for example in my experience let's say the way in which we use an air spectroscopy or that we have seen that it can be used in air spectroscopy when we have seen that it can be operational is that for example if you go to a farm and you need to assess the I don't know texture then what you do is that yeah you take some samples of this farm to calibrate your your models but your models will be specifically for that farm they will not you will not be able to extrapolate and usually for example my experience in Brazil was that um with around 100 to 150 samples are enough for an area of 500 hectares so yeah around 100 samples are might be enough for for calibrating those models for this this big big area but of course the bigger the area it might be the depends on the parameters of course and also the bigger the area the the more samples you might need and this is one of the the the challenging also questions that we are that we might um try to solve in in the context of the project of the of the soil spectroscopy project yeah i'm not not sure if i you see this last question it but i don't know if it's a question depend on the diverse of samples more diverse and need more samples do you understand yeah i think that yeah this is more a remark and i agree with that remark basically what in in an all words in other words is that the larger the diversity of your area the the larger the number of the samples that you might need to calibrate models for that specific perfect um i hope that um you're all happy is there any other question remark just before we close the meeting if not well i read a lot of expression of appreciation toward the Leonardo and the Stefania so thank you very much i think this was a very super training session as they define it so thank you very much really very much much thanks to you uh and thank you also to all participants that stood with us till the end of today and we are looking forward to see you tomorrow so thank you very much and see you tomorrow bye take care bye