Positive and negative ion chemical ionization mass spectrometry of pyrethrin pesticides

Abstract

Using both positive and negative ionization we report the methane chemical ionization mass spectra of technical grade pyrethrin samples. Preferred fragmentation modes involved cleavage around the ester oxygen single bond with one fragment appearing in the positive, and the other in the negative ionization mass spectrum with their sum being equal to the molecular weight of the pyrethrin. Using pulsed positive ion negative ion chemical ionization mass spectrometry we were able to quantify trans-permethrin at the low pg level of detection.