A Top Solvent‐Additive‐Ionization Technique Combination for Pesticides Direct Infusion MS Analysis

The leading type of ionization technique in mass spectrometry analyses is the ionization at atmospheric pressure. The aim of this study was to assess ESI and APCI ionization efficiency of pesticides introduced to the MS source in four organic phases, non‐doped and doped with formic acid and ammonium formate. Ionization efficiency in modified ESI and APCI, applying in‐source sample heating, was also assessed. The study was primarily designed to support non‐chromatography‐based mass spectrometry pesticides analysis by the direct infusion technique. Evaluation of analysis performances such as calibration performances, detectability, and sensitivity should indicate a top solvent‐additive‐source combination, leading to the highest ionization efficiency and lowest analytes detection limits.