Autosampler Guys - Blog

Autosampler Guys - Wednesday, October 09, 2019

VOC - Analysis in Water Samples Using Headspace - GC/MS Optimization in Several Steps……

 
VOC - Analysis in Water Samples Using Headspace - GC/MS Optimization in Several Steps……

Volatile hydrocarbons, VOC’s, especially in drinking water, place great demands on one's analysis system. In particular, highly volatile compounds such as chloromethane, dichlorodifluoromethane and vinyl chloride repeatedly cause problems for analysts with respect to the peak shape and thus the sensitivity of the analysis. This application optimizes the standard method, Headspace-GC-MS, in two steps to significantly increase sensitivity, especially in the case of highly volatile compounds.

Starting from the standard method, headspace injection, split 10: 1, in the first step, the injection is conducted in splitless mode to avoid split losses. To refocus the analytes at the beginning of the column, the eTrap Plus from CHROMTECH (-20 ° C) is used. In the second step, instead of the classic headspace injection, a SPDE extraction is used in which, analogous to the SPME technique, an internally coated cannula is employed, on which the analytes are concentrated at -15 ° C (Extraction Cooler). All measurements are carried out using the same EPA 624 VOC standard, the sample preparation times (incubation and extraction times are always 10 min.)