Practical aspects in gas chromatography–mass spectrometry for the analysis of pesticide residues in exotic fruits

• Published in: Food chemistry 2015-09, Vol.182, p.14-22
• Main Authors: España Amórtegui, Julio César, Guerrero Dallos, Jairo Arturo
• Format: Article
• Language: English
• Subjects: Analyte protectants (AP); Concurrent backflushing; Fruit - chemistry; Gas Chromatography-Mass Spectrometry - methods; Gas chromatography–mass spectrometry (GC–MS); Large volume injection (LVI); Pesticide Residues - analysis; Pesticide Residues - chemistry; QuEChERS; Tropical fruits
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2015.02.113

•Solvent vent parameters were optimized enhancing the sensitivity of the GC–MS.•The analyte protectants notably improved the quality of peaks in spiked extracts.•Quantitation of most pesticides was allowed at 0.010mgkg−1.•Backflushing, LVI and AP provide conditions for compliance check in fruit matrices. The most relevant parameters of a multimode inlet were optimized to increase the injection volume up to 25μL using solvent vent mode in order to improve the sensitivity of the gas chromatography–mass spectrometry system. Consequently, the implementation of a concurrent backflushing was necessary to largely prevent the expected loss of performance derived from such matrix load out of a general-purpose extraction (EN-15622-QuEChERS). Additionally, four mixtures of compounds used as analyte protectants were tested using spiked physalis to enhance the quality of signals. The chosen mixture remarkably improved sensitivity and yield better peak shapes, significantly more than others also tested. The analysis of pesticide residues in exotic fruits using instruments of limited selectivity is challenging since these complex matrices usually give notably dirty extracts. This scheme included an instrumental optimization and the addition of selected compounds that enabled to selectively reach limits of quantitation of 0.01mgkg−1 for most analytes.