Advanced GCxGC-MS Strategy for Pesticide Analysis in a Highly Complex Chili Pepper Matrix

Analytical determination of pesticides in chili peppers is highly challenging due to the complex matrix, which is rich in capsaicinoids and other lipophilic compounds that can significantly interfere with chromatographic analysis. Conventional chromatographic setups for routine pesticide analysis based on gas chromatography coupled to tandem mass spectrometry (GC-MS/MS) resulted in co-elution problems for several analytes with dominant matrix components.

In this study, a method for the determination of a broad spectrum of pesticide residues in fresh and dried chili peppers was developed, optimized, and validated using QuEChERS extraction followed by comprehensive two-dimensional gas chromatography coupled to mass spectrometry (GCxGC-MS, Pegasus BTX). 

The method was validated in accordance with the requirements of SANTE/11312/2021 (V2). For the majority of target pesticides, recoveries ranged between 70 and 120 %, with relative standard deviations below 20 %. Limits of quantification reached low µg/kg levels despite the complexity of the matrix.

Analysis of real samples confirmed the presence of multiple pesticide residues in all analyzed samples, with dried chili exhibiting a higher frequency and concentration of residues compared to fresh chili.

These findings confirm the high level of pesticide contamination in chili peppers and demonstrate that GCxGC-MS is a powerful and reliable tool for pesticide residue analysis even in such complex matrices.