Determination of multiresidue pesticides in Arabian dates using LC and GC Triple Quadrupole Mass Spectrometry

Importance of the Topic

Dates are widely consumed in the Middle East and North Africa and are prone to pesticide contamination due to extensive agricultural practices. Accurate multi-residue analysis in this high-sugar matrix is essential to ensure food safety and comply with regulatory limits.

Objectives and Study Overview

This study aimed to develop a sensitive and reliable analytical workflow for the determination of over 400 pesticide residues in dried dates. It combined GC-MS/MS and LC-MS/MS using triple quadrupole mass spectrometers and a modified QuEChERS extraction approach. Method development focused on database-assisted MRM transition selection and retention time alignment.

Used Instrumentation

• Shimadzu Nexera series UHPLC coupled with LCMS-8060 triple quadrupole mass spectrometer
• Shimadzu GCMS-TQ8050 NX triple quadrupole mass spectrometer with SH-Rxi™-5Sil MS capillary column
• LabSolutions Insight Screening™ software for data processing and spectral library comparison

Methodology

A modified AOAC 2007.01 QuEChERS protocol was applied to 15 g of homogenized date samples. Extraction used 1% acetic acid in acetonitrile with magnesium sulfate and sodium acetate salts. Cleanup employed dSPE with PSA and C18 sorbents. Matrix-matched calibration standards (2–100 ng/mL) were prepared by spiking blank extracts. Pre-extraction spike recoveries at 10 and 40 ng/mL were evaluated to assess accuracy and precision. Automated retention time adjustment and MRM method creation utilized Shimadzu’s pesticide database and AART algorithm.

Key Results and Discussion

• 405 pesticides analyzed: 200 by GC-MS/MS (24 min run) and 205 by LC-MS/MS (15 min run).
• Calibration curves showed linearity (r² > 0.995) across 2–100 ppb in matrix.
• Recoveries ranged from 70% to 120% for most compounds; only two pesticides fell outside SANTE/11312/2021 guidelines.
• Pre-extraction spike RSDs were below 20%, indicating good repeatability.
• Optimized temperature program achieved baseline separation of cyfluthrin and cypermethrin isomers.
• Shimadzu’s Synchronized Survey Scan (SSS) and LabSolutions Insight facilitated rapid screening and reduced false positives/negatives.

Benefits and Practical Applications

The combined GC-MS/MS and LC-MS/MS workflow delivers high-throughput, sensitive, and robust quantitation of a broad pesticide panel in complex high-sugar matrices. It supports routine quality control in food safety laboratories and regulatory compliance testing for dried dates.

Future Trends and Applications

The approach can be extended to other challenging food matrices such as dried fruits, honey, and beverages. Integration with high-resolution mass spectrometry and machine learning-based spectral interpretation may further enhance screening capabilities. Expansion of spectral libraries and automated method optimization will streamline future multi-residue analyses.

Conclusion

The developed QuEChERS-based extraction combined with Shimadzu triple quadrupole MS platforms provides a reliable, accurate, and efficient solution for multi-residue pesticide analysis in dried dates. The protocol meets regulatory guidelines and can be readily implemented in analytical laboratories.

Reference

1. AOAC Official Method 2007.01 Pesticide Residues in Foods by Acetonitrile Extraction and Partitioning with Magnesium Sulfate.
2. Analytical Quality Control and Method Validation Procedures for Pesticide Residues Analysis in Food and Feed, Document No. SANTE/11312/2021.