gas chromatography acetylene reduction

[vinayaknio]

freinds,

please let me know what all things i should learn to begin with the gas chromatography for acetylene reduction.
I am provided with the shimadzu GC2010 machine and i am told to assay the acetylene from the water samples.
I really dont know anything else apart from the principles given in the texts..
kindly advice me.

thanking you.
vinayak

[Don_Hilton]

There are a number of things you need to know. I'll start off the list.

You need to know basic instrument operation, which includes:
- daily checks of the function of the instrument and maintanance
- use of the software and review of chroamtographic data
Your application requries some specific knowledge
- how to sample your water samples (head space sampling, direct injections, some kind of extraction technique)
- The nature of potential analytes - so that you will know how to be sure they do not interfere with the analysis of the acetylene.
- how to make up standard mixtures to calibrate the instrument.

Depending on how much you know, these may be easily acquried or you may find that these will take you too much time to allow for a practical solution. It would help if there is someone who cold look at your instrument and data and give you advise. This is not a project I would assign to a novice without providing considerable supervision.

[vinayaknio]

thank you very much Hilton.
your advice is useful and following the same i will start my work.
daily checks and maintenance issue i have noted down..
software part i will look into it... by tomorrow.. how to make a review of data i shall understand once i start the analysis.
regarding sampling is concerned... i have the details and sampling procedure i have some tutorials that i can follow..
to tell you more precisely, i wish to look into the water samples which are showing evolution of nitrogen gas inside themselves..so i will have to keep them at room temperature for 24 hours...then in that time period whatever ethylene i have injected(prior to the analyis) into the sample would have converted to acetylene..... i will have to sample the head space for that evolved acetylene (in otherwords its measure of nitrogen evolved from the sample) and inject into the GC.. to know the amount of ethylene to acetylene..
caliberation i think i will have to do with the acetylene gas standard..kindly tell me if i am wrong..
one more doubt which i have is.... i will have to use capillary column or packed column? i also dont know what is the difference between them..
thank you again for the kind sharing of knowledge..
vinayak

[Don_Hilton]

For data review, you need to know how a properly integrated chromatographic peak should look. And you need to be able to distinguish chromatograms in which there are problems, such as interfereing peaks or chromatographic problems due to sample issues or column degredation.

As far as what column to use. Your instrument came configured for one type or the other. As far as wether a packed or capillary column would be better - you may have the option of using one that fits your instrument. Analysis of gasses often uses a different slection of columlns that the ones I commonly use - so perhaps someone with experience in gas analysis can give you some advise.

There are a couple of important things that will help the person helping you: What kind of detector is on your GC? And is the instrument configured for capillary or packed columns? And are there any gasses that might be expected in your mixture beyone ethylene, acetylene and nitrogen.

For standards, you need to have a known quantity of the analyte in a known volume for injection into the GC or in a known ratio with other components in the mixture. Just taking a sample of acetylene gas and injecting it will not be sufficient to calibrate the instrument to determine conversion between ethylene and acetylene.