A gas chromatographic/mass spectrometric (GC/MS) confirmation procedure for 10 phenyl-N-methyl-carbamate insecticides in liver tissue was developed. The extract from liquid chromatography (LC) is purified with a C18 solid-phase extraction cartridge and then derivatized with heptafluorobutyric anhydride; the derivative is injected for analysis by GC/MS with electron ionization and multiple ion monitoring. The identity of the derivative is confirmed by comparison of its retention time and relative intensity data with those of a standard. Liver extracts from the LC procedure containing carbamates at 10 ppb levels were successfully confirmed by this procedure.

Liver samples of bovine, swine, and poultry were fortified with 0,5,10, and 20 ppb mixed standards of an additional 6 carbamates as part of a method extension study. Each of the 3 species in this study was analyzed 4 times at 0,5,10, and 20 ppb fortification levels. The average of 12 recoveries of 6 carbamates at all 3 fortification levels was greater than 90%, with a maximum coefficient of variation less than 18%.