Chromatography Forum

I'm working on a project with a college senior for her senior project. We are attempting to measure the acetic acid concentration in the secretion of a whip scorpion, or "vinegaroon". When threatened the whip scorpion will secrete an acetic acid mixture. The student has collected several samples. I'm having difficulties getting a CG-MS method to work. Can someone help me develop an acetic acid method on a GC-MS? I'm not getting separation from dichloromethane or methanol solvents.

I'm using a shimadzu QP5000 (gc-17a) with "slb 5ms" 30m column.

Any suggestions welcomed.

Acetic acid on a 5ms type column is going to be tricky to start with, as acetic acid typically gives a very poor peak shape - unless you derivatize the acetic acid.

In methanol, you are likely to esterify a significant portion of the acetic acid.

I would suggest a more polar column, possibly a carbowax type.

If you look around on the internet, there are a number of procedures - one of interest is: http://chemlab.truman.edu/Instrumentation/pdf/gcms.pdf, which uses water as a solvent and a FFAP column. That procedure may give you some ideas. (And, yes, you can inject water on a GC column and expect the column to live.)

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Thank you Don. I'll give it a try.