Determination of Multiclass, Multiresidue Pesticides in Bell Peppers

Importance of the Topic

Bell peppers are widely consumed vegetables that can accumulate residues of multiple pesticides. Reliable detection of these residues is essential for food safety, regulatory compliance, and prevention of health risks. Matrix pigments and co-extractives in peppers may interfere with analytical instrumentation, requiring robust cleanup methods to ensure accurate and reproducible results.

Objectives and Study Overview

This study aimed to develop and validate a unified workflow for the simultaneous determination of 230 multiclass pesticide residues in mixed-color bell peppers. The method combines QuEChERS AOAC extraction with Agilent Captiva EMR–GPF passthrough cleanup, followed by analysis on both liquid chromatography tandem mass spectrometry (LC/MS/MS) and gas chromatography tandem mass spectrometry (GC/MS/MS).

Methodology

Homogenized bell pepper samples (15 g) were extracted using Agilent Bond Elut QuEChERS AOAC kits. A 3 mL aliquot of the crude extract was loaded onto Captiva EMR–GPF cartridges for gravity passthrough cleanup, removing pigments and lipids while preserving analytes. For LC/MS/MS, eluent was diluted to 20/80 acetonitrile/water. For GC/MS/MS, the eluent was dried with anhydrous MgSO4 to eliminate residual water before analysis.

Instrumentation

• LC/MS/MS: Agilent 1290 Infinity II UHPLC coupled to 6490 triple quadrupole with Jet Stream iFunnel electrospray source
• GC/MS/MS: Agilent 8890 GC with 7000D triple quadrupole, multimode inlet, and backflushing system
• Software: Agilent MassHunter Workstation for data acquisition and processing

Main Results and Discussion

Compared to traditional dispersive SPE with graphite carbon black and two alternative dSPE kits, Captiva EMR–GPF cleanup delivered superior matrix removal (>95% pigment reduction), cleaner LC-UV and GC full-scan baselines, and minimized interferences. Recovery and reproducibility at 10 ng/g fortification showed over 98% of targets within 60–120% recovery and 99% with RSD ≤ 20%. Matrix effects in LC/MS/MS were reduced to within 70–130% for 94% of analytes. Overall failure rates for recovery, precision, and calibration linearity (R2 > 0.99) were below 7%.

Benefits and Practical Applications

• Single cleanup workflow supports both LC/MS/MS and GC/MS/MS analyses
• Eliminates multiple centrifugation and vortex steps, reducing hands-on time
• Enhances analyte recovery for sensitive compounds
• Reduces matrix effects, prolongs instrument uptime, and improves data quality

Future Trends and Potential Applications

The Captiva EMR–GPF approach may extend to other high-pigment fruits and vegetables, veterinary drug analysis, and mycotoxin screening. Integration with automated sample-preparation platforms and expansion to emerging contaminants could further increase laboratory throughput and analytical robustness.

Conclusion

The combination of QuEChERS AOAC extraction and Captiva EMR–GPF passthrough cleanup provides a fast, simplified, and reliable method for comprehensive pesticide residue analysis in bell peppers. The workflow achieves high recovery, excellent precision, minimal matrix effects, and broad analyte coverage on both LC/MS/MS and GC/MS/MS platforms.

References

1. González-Curbelo MA, et al. Trends in Analytical Chemistry 2015;71:169–185.
2. Varela-Martínez DA, et al. Liquid-Phase Extraction Handbooks in Separation Science 2020;Chapter 14:399–437.
3. Zhao L, et al. J Chromatogr A 2018;1549:14–24.
4. Lucas D, Zhao L. Agilent application note 5991-8694EN;2017.
5. Zhao L, Wei T. Agilent application note 5994-4764EN;2022.
6. Zhao L, Wei T. Agilent application note 5994-4765EN;2022.