Partial List of Potential Problems That Can Occur in the Headspace-GC/MS Analysis on Aqueous Extracts (VOC Analysis) That Could Lead to Omission of Compounds, with a Suggestion on How to Potentially Avoid These Omissions
| Headspace-GC/MS on AQUEOUS EXTRACTS | |||
|---|---|---|---|
| Type of Problem | Description of Problem | Potential Omissions | How to Avoid Omissions |
| Sample preparation – Sample introduction | Compounds with high water solubility will poorly partition into the headspace, reducing sensitivity | Low MW Acids, Alcohols, Amines, thiols, etc. … | Low MW Acids: Aqueous extracts via Ion Chromatography Amines & thiols: Use orthogonal analytical methods that show a sufficient response for these compounds (LC/MS ESI; derivatization GC/MS) Verify the results of the neat Headspace-GC/MS analyses |
| Chromatography | Compounds eluting in the solvent peak (when analyzing WFI/Alcohol-mixes) | Isomers of pentene, pentane, diethyl ether, isomers of pentadiene, ethyl formate, carbon disulfide, acetonitrile, etc. … | Verify the results of the neat Headspace-GC/MS analyses Consider Mass Spectral Deconvolution options in combination with an Internally Developed Mass Spectral Database |
| Chromatography | Reactive compounds may hydrolyze or polymerize in aqueous sample. | Silanes, conversion of trimethylsilanol to hexamethyl-disiloxane, 1,2-ethanediol diformate to methyl formate and ethanol, etc. … | Verify the results of the neat Headspace-GC/MS analyses |