 So what we want to do now is look at a couple of different types of outputs together to see if when we work through the process we can actually get to a solution. Here are some outputs and the question is what is this organic compound? So the first thing that I want to look at is the mass spectra. The mass spectra is telling me that the maximum value here, the molar mass, is 74. So that's a good starting point that gives me a little bit of information that might be useful to me at some point. I also have when I look at mass spectra a peak at 57, 74 minus 57. So that's going to be 17. Now 17 is an interesting number because 17 is equal to 16 plus 1. Now I know 16 plus 1 is an OH group. So it's possible that this is already telling me something about the presence of a hydroxy muscle group. There's another peak here at 45, 74 minus 45. Now this time I have 29. Now 29 is also an interesting one that I've looked at in the past. You may want to have a look at a few different variations and of course there can be more than one but 129 that I know comes up quite often is an ethyl group. So C-C-H-H-H-H. So what we have here is two 12s, 24 plus five 1s is 29. So I have a fragment here that has an ethyl group on it, a hydroxyl for the first one and an ethyl for the second one. So there's a couple of little bits of potential clues that I have. Of course other other combinations that might bring me a 29 maybe so I need to explore a few more things if I'm going to be sure about what I actually have here. The fact that there's no UV-Vis above 220 means we probably don't have a double bond. We probably don't have any of those complications in this particular molecule but we're not sure because no information doesn't necessarily tell us anything definitive but I'm just making that little conclusion at this point in time. So now I'm going to go up to the IR spectrum. Now the IR spectrum is showing me something interesting because I would expect a nice broad tongue for around the 3000 region up here to indicate the presence of the OH group that I think got cracked off this molecule. But when I look at it it's not the tongue, it's the hairy beard. So that means that I've potentially got a C00H group. So I can confirm that by saying okay well that sort of broad region around where I expect it is where an OH appears but the hairy beard one is more an indicator of the carboxylic acid group than the OH group. So of course one of the really important things I can do is I can look at where the carbon oxygen double bond is and that sits in that 1680 to 1750 region and as we've already looked at in a previous example there it is right there. So that is actually confirming to me the presence of the C00H group because I've got that hairy beard so I've got the broadness up where the OH group is but I've also got the presence of that a C double bonded O. So now I'm starting to be a little bit more confident that I might actually have a carboxylic acid here. Now what I can do since I've got both of these outputs together is just do a quick calculation. So for my C00H group I haven't calculated one of them before but if I've got one carbon that's 12 and then I've got 16 and another 16 for the other oxygens and a hydrogen so let me see what I've got here I've got 8, 14, 15 and then 45. So notice that 45 is the value of the mass of a C00H group and of course when I look back here 45 is one of my fragments so therefore that means that could actually have cracked off from that molecule and it'd be sitting on its own as it's passing through the mass spectrometer. So now I'm starting to feel quite good about my identification of this molecule. I think I've already got enough information here that I'm close to being able to put it together but just to be sure let me have a look at my NMR data. So when I look at my NMR data now I have one, two, three. Let's not worry about the top one just for the moment. Let me look at my three different types of environments. So my three different types of environments tells me that I have at least three carbons and this is starting to be consistent with what I have before. Notice too that one of these carbons is way, way to the left and usually this is an indicator of one of these more unusual bonds. So let me just go to my chart and see if each of these things make sense. So 5 to 40 is the carbon-carbon hydrogen bonds so that could be this region here. It could also be this region here. My marker on the 29-ish kind of mark looks like it's coming in somewhere around here. So this one is a very low value. It's around about the 10 mark. This one here is more like around about the 29 mark and so it's possible that I have this. It's possible that I may also have, if it's a 29 mark it could be this or it could be this, it potentially could even be this and then my final one is a really big one. It's up at 180 and up at 180 you can see what I've got up here is this one here. So there's another piece of confirming evidence that suggests to me that this is actually an acid. It could be an ester but what I looked at from my IR and my mass spec suggested that this probably was an acid. Now if this is an acid this would mean that this confirms this one and it also confirms this one because I know I've got more than one carbon. I'm not thinking I've got three C00H groups. I'm thinking that there are different types of environments so that's more consistent with the fact that I've got these carbons attaching in these different kinds of ways. So this is another little piece of confirmation. So I'll then finally look at my NMR. The NMR is a little bit difficult to read here but you can see that there are a couple of regions for hydrogens and these regions for hydrogens are around the sorts of places we might expect. A peak of 3 and a peak of 4 this indicates that we've got something sitting next to a CH3 neighbor and this sitting next to a CH2 neighbor and we might expect another one way up the end for that hydrogen that's sitting on the oxygen that's attached to another carbon. It's not on this output here but you can see the line is just so contracted that the little blip is so far off to the left that it's actually being truncated and it shows it up there so we would expect that something's going on up there as well. So there are three different types of hydrogen environments. One up there on the oxygen and two others with those methyl and the CH2 neighbors. So I'm pretty confident now that I have a molecule that I can identify. It has this group which I got from MassSpec. I've confirmed, I feel like I've confirmed that I also have an acid group and therefore I feel pretty confident that I have propanoic acid which also goes by the more common name of propionic acid. It's my three carbon carboxylic acid and I think from the information that I've been provided with I can be reasonably confident in my conclusions that I found propanoic acid. There's a lot of steps in this and you can see some of them are confirmation steps not necessarily critical steps but I think once you've started to put some of this information together particularly with the info from MassSpec and IR if you leave the NMR to the end and look at it more as confirmation I think it's harder to start from NMR. It's better to come back in and use it as confirmation. Hopefully this is a useful little technique for working through the different types of spectra in order to identify an unknown. Good luck, do plenty of practice and thanks for watching.