Determination of Pesticides in Foods using Dopant-optimized Gas Chromatography-Atmospheric Pressure Chemical Ionization Quadrupole-Time-of Flight Mass Spectrometry

Overview

A dopant optimized GC-APCI Q-TOF method for screening of pesticides in food matrix was developed. Dopant optimization studies found methanol as the optimal organic modifier using the Bruker GC-APCI II source. The developed technique utilizes facile dopant vapor introduction via nitrogen carrier gas and can be used to selectively enrich ionization for different classes of pesticides.

Introduction

Soft ionization modes in GC-hyphenation studies such as chemical ionization (CI), field ionization (FD), supersonic molecular beam (SMB), or atmosphericpressure chemical ionization (APCI) allows the effective formation of pseudo-molecular ions from biomolecules. Soft-ionization techniques thus allows users to address a much wider scope for screening as well as improved identification confidence based on stable pseudomolecular ion. GC-APCI generic source coupling is one of the more promising method as it is dually compatible with both GC and LC-hyphenated mass spectrometers. In this study, the optimization and development of a dopant-based APCI screening workflow using nextgeneration GC-APCI ion source on a QTOF platform for multi-target pesticide screening is presented.