Gas Chromatography GC

[callmehoo]

Hello. I want to ask about GC TCD-thermal conductivity detector can u show a video about it?

[ncpatch]

Any one know what viscous means?

[callmehoo]

@ncpatch If a liquid is viscous that implies that the liquid has resistance to flow. For example petroleum gel and water, which is more viscous? The answer is petroleum gel as it flows more slowly than water across a slanted plane.

[bonny247]

hii friends can any one give me information on  what compounds can be dervitized??? and what is the exact method for sample extraction with the use of derivatizing reagents?? lidocaine, procaine mesalamine bupivacaine topermate can any of these be dervatized??

[crudeoilsystems]

very nice. Thanks

[hplcflowmeter]

thanks

[shaggyburns]

how do you know which compound each peak is?

[shortie177]

@shaggyburns you need to use the external, internal standard or standard addition method of anlysis to determine which peak is which if you have unknowns.

[BuickDoc]

@shaggyburns One method I used is called preparative gc. A larger column and a larger volume of injectate is used. As the carrier gas exits the machine, dry ice cooled traps are inserted in the gas stream. Any liquids are thus trapped. Change the trap for each peak on the chromatogram, to isolate each compound. They can then be identified by standard methods, ie IR, NMR, Mass Spec, etc. Another method is to use a GC/Mass Spectrometer. High resolution MS will usually give a unique structure.

[asteriscotriangulado]

Awesome! :D

[angelzpoo]

I didn't think you had to use the detector? Isn't it destructive? The GCMS does not have a detector because it is the ms aspect does that job??? is the gcms form of testing destructive?

[angelzpoo]

I didn't think you had to use the detector? Isn't it destructive?

[Jerby7]

Hello,

Does the GC detects a concentration or a number of mole?

I hope my question is clear enough to understand

[analychemist]

@Jerby7

GC detects relative amounts of some analyte. To find concentrations, usually you do the method of internal standards. You compare the area ratio between what you want as an analyte and some standard which has a fixed concentration of your choice. You make standards of your analyte (using known amounts of the analyte) with the standard to make a calibration curve. From the curve and running your unknown, you can find concentration.

That's probably more than what you wanted lol.

[Jerby7]

thanks for sharing!

[goalone09]

thank you very much.

[Sarimperil]

Very informative and easy to understand! Thank you!

[farahfd20]

very helpful video

[vamsipalaka]

thank u very much.

[Ezequiel9425]

thanks

[naturalfeatures]

Awesome... this is a great resource for preparing for organic lab

[Thijswvv]

Thanks!

[GingleGangle1]

Is it possible to see the ratio of CH3OH and C2H5OH in water with this method?

[GingleGangle1]

Is it possible to see the ratio of CH3OH and C2H5OH in water with this method?

[zzanzak]

I am building a gas chromatograph. I need some design parameters and a diagram for a Wheatstone bridge for my GC. Please help me.

Thank You

Zan

[Puddy88]

Thanks a lot for this video.

[forfuneee]

Thank you

[nanigad]

this is very useful video.thanks for nice explaining

[rajeevvarma84]

Thank you so much ...... I'll be giving a lecture on Gas chromatography in 12 hrs ... I'll be showing this video via internet thanks a million RSC !!!!

[suneetha4]

thanks alot for posting this video...i hope to get many informative videos in the future

[AlgerienBiologist]

thanks

[darthsedious2000]

since GC heats up the anlyte or specimen before the measurement or identification thus most organic substances like protein could not be evaluated or tested accurately or am I wrong please advice

[nbo345]

@darthsedious2000

the sample is heated quickly after it is injected into the injection port where it is vaporized then carried to the (nonpolar or polar) column.(Preferably, nonpolar column are used to prevent bleeding) This also regards the polarity of the sample and the column wall. Organic or inorganic samples can be tested. In this case protein, it must be homogenized into liquid form before using GC. Other parameters also play a factor in the identification of analytes in the sample

[andoniashley]

This video is excellent !

[pells09]

polarity has more to do with hplc, gc is the simple version og heating ur small liquid sample and breaking down the constituents of ur mixture for u to idenify through retention times and area peaks

[MrJason1234]

To Traxass000

factors which will affect the retention time of the compounds are;

volatility

polarity

column temperature

column packing polarity

flow rate of the carrier gas

length of the column

Volatility will generally be the main factor influence the separation. Polarity is only important if the mixture of compounds has compounds with widely different polarities.

Good luck on your project

[bellinivernon]

Exelente ! ;gracias ,desde buenos aires.

[thudu15]

Really useful video :-) I'd be interested to see answer to traxass000 about precisely what is mean by volatility - does it refer to polarity?

[markytproctor]

Thanks for the video... It help me alot! =D

[sdoubaa]

interesting

[traxass000]

i got a question here. so GC has nothing to do with the polarity of the substances used in order to separate them (because my teacher keeps on saying the polarity plays an important roll, like the more polar particles remain behind while the rest goes through the tube) ? because here and on other videos i here people mention only volatility of the substances as an important factor. :S :-? need explanation asap help help :p:p its for a project and great vid btw ;)

[sparklingwine16]

actually its more dependent on the volatility of the substances in your mixture. The more volatile compound in your mixture will be eluted (driven off) first followed by the less volatile, then lastly the least volatile one. Therefore you must know the boiling point of the substances in your mixture.

[MrJason1234]

There are about 6 factors which will influence the retention time of the compounds in GC;

Volatility of the compound

Polarity

Column temperature

Column packing polarity

flow rate of the carrier gas

and length of the column

Volatility will have the greatest influence on the separation. Polarity is only important if you are separating compounds with widely different polarities.

Good luck on your project.

[pells09]

polarity has more to do with liquid chromatography compared to gc, you familiar with the saying 'like dissolves like' and so on, gc just heats ur liquid sample, and breaks it down for a chemist to identify constituents of a mixture through their retention times and areas.

[sam4phd]

Well polarity indeed plays an important role as it defines the extent to which a given sample molecule interacts with the given GC column. There are specific columns depending on the type of sample molecules you need to analyse. I hope this helps :)

[shoukatkhan01]

Hi,

yes in GC the separation of analyte depends on its volatility but we should keep in mind that more polar the compound less volatile it would be,second thing the polarity of column in GC is also very important bcz inside the column the analyte molecules do not travle in a very straight line they move randomly and when they come in contact with the walls of coulmn they stay there for a while depending upon the polarity of analyte and column.

[Yibitech]

@traxass000 The components are sticking and being released LOTS of times. That stickiness has to do with the polarity of the column, and the polarity of the sample. Volatility is ease of evaporation. The particles are sticking to the coating on the stationary phase, coming off, and sticking again. Like dissolves like, so a polar chemical will stick and release to a polar column more times, thus coming off the column slower.

[sweetprinci]

Very good. thanks

[Tescanna]

Thanks, this was very useful!

[chemistosama]

thanks

[chemistosama]

thanks

[chemistosama]

thanks

[robecbecs]

thanks for posting this video. Very informative.

[alexrs2k]

Thank you!

[macmenmen]

Thanks for posting