Gas chromatography

Chromatography Forum: GC Archives: Gas chromatography
Top of pagePrevious messageNext messageBottom of pageLink to this message  By Anonymous on Monday, December 23, 2002 - 11:37 am:

Hi I am having problemms understanding the concept behind GC i know it is alot like TLC but i have to do a formal lab report for organic chemistry. All i know is that GC seperates compounds in a qualitive aND qunatitive way. to be more specific i need to know how to caluculate amount[relative to total alkene yield in chromatogram #1]% i have the rentention times and amount (area) here 4 values for each. just unsure of calculation that must be done..
The rxn is 2-bromopentane and sodium ethoxide retention times are 3.52,7.26,8.75,9.87 and amount (area) are 272.5,1172.8,403.0,649.3 if anyone could point me in the right direction that would be much appreicaited...


Top of pagePrevious messageNext messageBottom of pageLink to this message  By Mel on Monday, December 23, 2002 - 01:54 pm:

From reading your question, it is obvious that you do not understand the basic prinicipals of chromatography. Chromatography is the science of separation. You have a stationary phase and a mobile phase. In TLC, the plate is the stationary phase and whatever solvent is in the tank acts as the mobile phase. For GC, the column contains a packing which is your stationary phase. There are many different columns to choose from and it is dependent upon your analyte of interest. Helium is usually the carrier gas used and is the mobile phase for GC.

The end result is a chromatogram containing peaks at various time points which represent certain analytes. The peaks will have different responses depending on how much was contained in the sample. You usually have a standard with a known concentration and can then analyize your unknown sample by comparing the peak areas of the unknown to the known and multiplying by the standard amount known.

I want you to understand the principles behind chromatography and how it is a powerful analytical tool. Don't focus on the answer but the process that leads you to the answer. I hope this helps.

Mel


Top of pagePrevious messageNext messageBottom of pageLink to this message  By jumin tresa jose on Monday, January 6, 2003 - 02:50 am:

i am doing my m.tech pharmaceutical chemistry in vit.i want to give a seminar on high resolution gas chromatography.i am not aware of any thing regarding the recent developments.will u please send me instrumentation,working,adv,appliction of it.i will be grateful to you


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