Chromatography Forum

Hi, can anyone suggest probable source of contamination of acetic acid in GC analysis.i got OOS results for acetic acid solvent during analysis of raw material sample.the contamination limited to GC liquid analysis vials,results are OK from same flask as a part of verification.so what are the causes for vial contamination. Used fresh vials for analysis and no any standard carryover observed.

Acetic acid (anhydride) is commonly used to manufacture the acetate ester of the organic acid drug product for stability purposes. That there should be some left over is not surprising.

Hi, can anyone suggest probable source of contamination of acetic acid in GC analysis.i got OOS results for acetic acid solvent during analysis of raw material sample.the contamination limited to GC liquid analysis vials,results are OK from same flask as a part of verification.so what are the causes for vial contamination. Used fresh vials for analysis and no any standard carryover observed.

Welcome to the forum.

The most straightforward explanation for an OOS result is that the sample was indeed OOS. Why do you think that contamination is more likely than an OOS sample ?

Peter

Thanks for your reply, but acetic acid results found good from same initial preparation (aliquot). I want to find source of contamination during initial vial filling.my initial filled vials are got contaminated. I injected same OOS yielded vials again for verification,where I got almost same result.

Some more details of your sample, analysis and analytical conditions would be helpful

Just to clarify
Are you saying that a sample injected from a flask is within spec but exactly the same sample placed in a gc autosampler vial and injected is out of spec?