Method for the determination of 243 Residual Pesticides in Red Chili Powder using LCMS-8050 and GCMS-TQ8040 NX

Importance of the Topic

This study addresses the critical need for reliable detection of pesticide residues in red chili powder, a commonly used spice with a complex matrix that often retains agrochemical contaminants. Ensuring compliance with international maximum residue limits (MRLs) safeguards consumer health and supports regulatory surveillance.

Objectives and Study Overview

The primary goal was to develop and validate a fast, robust multi-residue method capable of quantifying 243 pesticides in red chili powder using two complementary platforms: ultra-fast LC-MS/MS (LCMS-8050) and GC-MS/MS (GCMS-TQ8040 NX). The approach aimed to cover both polar and non-polar compounds and achieve trace-level limits of quantification (LOQs) in a single extraction workflow.

Methodology and Instrumentation

Sample preparation employed a modified QuEChERS protocol: acetonitrile extraction, salting out with sodium chloride and MgSO4, followed by cleanup using a mix of C-18, GCB, PSA and MgSO4 to reduce co-extractives.

Instrumentation details:

• LC-MS/MS: Shimadzu LCMS-8050 coupled to Nexera X2; Raptor Biphenyl column (100×2.1 mm, 2.7 µm); ESI positive mode; MRM transitions; mobile phases of ammonium formate/formic acid in water and methanol; run time 22 min.
• GC-MS/MS: Shimadzu GCMS-TQ8040 NX with AOC-20i + s injector; SH-Rxi-5Sil MS column (30 m×0.25 mm, 0.25 µm); EI mode; splitless injection; helium carrier; run time 25 min.
• Calibration: matrix-matched standards (0.1–10 µg/L for LC, 1–50 µg/L for GC); weighted (1/C2) linear regression; six fortified replicates at three levels for recoveries.

Main Results and Discussion

Linearity was excellent (R2 > 0.98) across both platforms. At LOQ levels (5 µg/kg for most compounds), mean recoveries fell within 70–120% and both repeatability (RSDr) and reproducibility (RSDR) were below 20%, meeting SANTE criteria. The method achieved 5 µg/kg LOQs for 97 pesticides by LC-MS/MS and 41 by GC-MS/MS; additional compounds reached 10–50 µg/kg LOQs. Representative chromatograms demonstrated clear separation and sensitive detection even in the challenging chili matrix.

Benefits and Practical Applications

• High throughput screening of a broad pesticide spectrum in a single sample preparation.
• Sensitive detection at or below regulatory limits, enabling compliance testing.
• Reduced matrix interference due to optimized cleanup, improving instrument uptime.
• Compatibility with existing laboratory workflows and Shimadzu method packages for ease of adoption.

Future Trends and Potential Applications

Emerging directions include integration of high-resolution mass spectrometry for non-target screening, automation of sample prep, expansion of pesticide libraries, real-time monitoring in processing lines, and application to other complex food matrices.

Conclusion

The validated multi-residue method using LCMS-8050 and GCMS-TQ8040 NX provides a fast, reliable, and comprehensive tool for regulatory and quality-control laboratories to monitor pesticide residues in red chili powder at trace levels.

Reference

• M. Anastassiades et al., "Fast and Easy Multiresidue Method Employing Acetonitrile Extraction/Partitioning and ‘Dispersive Solid-Phase Extraction’ for the Determination of Pesticide Residues in Produce," J. AOAC Int., 86, 412–431 (2003).
• Guidance document on analytical quality control and method validation procedures for pesticide residues and analysis in food and feed, SANTE/12682/2019.