Method for the determination of 326 Residual Pesticides in Rice using LCMS-8045 and GCMS-TQ8040 NX

Importance of the Topic

Rice is one of the world’s most important staple foods, with significant pesticide usage during its cultivation. Ensuring that residual pesticide levels remain below regulatory limits is essential for consumer safety and international trade. Analytically robust and high-throughput methods are needed to monitor a wide array of pesticide chemistries at trace levels in complex agricultural matrices.

Objectives and Study Overview

The primary goal of this study was to establish a single extraction, multi-residue workflow capable of detecting and quantifying 326 pesticides in rice. Shimadzu’s LCMS-8045 (coupled to Nexera X2) and GCMS-TQ8040 NX platforms were selected to extend coverage across polar and non-polar analytes. The method was benchmarked against SANTE guidance for specificity, linearity, accuracy, precision, and limits of quantification (LOQs).

Methodology

A modified QuEChERS protocol employing acidified ethyl acetate and anhydrous salts enabled efficient extraction of pesticides from homogenized rice. After partitioning, the extract was split for parallel clean-up tailored to each instrumental technique. For LC-MS/MS, C-18 and PSA sorbents were used to reduce matrix interferences, while GC-MS/MS cleanup incorporated C-18, PSA and MgSO₄. Final sample concentrates were reconstituted in appropriate solvents to achieve target fortification levels.

Used Instrumentation

• LC-MS/MS system: Shimadzu LCMS-8045 with Nexera X2 autosampler
• GC-MS/MS system: Shimadzu GCMS-TQ8040 NX with AOC injector
• Columns: Shim-pack XR-ODS II (150×3.0 mm, 2.2 µm) for LC; SH-I-5Sil MS (30 m×0.25 mm, 0.25 µm) for GC
• Data processing: LabSolutions Insight software with Method Package Ver. 3 and Smart Pesticides Database Ver. 2

Main Results and Discussion

Matrix-matched calibration provided linear response from 2 to 20 µg/L (4–40 µg/L for certain analytes), with correlation coefficients exceeding 0.97. The method achieved LOQs of 10 µg/kg for 170 compounds and 20 µg/kg for an additional 96 compounds; four targets required LOQs of 40 µg/kg. Mean recoveries at the LOQ levels ranged between 70 % and 120 % for most analytes, with relative standard deviations for repeatability (RSDr) and reproducibility (RSDR) below 20 %, in accordance with SANTE criteria.

Benefits and Practical Applications of the Method

• High throughput: Run times of 21 min (LC-MS/MS) and 25 min (GC-MS/MS) maximize daily sample throughput.
• Sensitivity: Low LOQs enable compliance checks at or below maximum residue limits (MRLs).
• Instrument longevity: Reduced injection volumes and flow rates help prolong column life and ensure stable performance during extended sample series.
• Regulatory compliance: Validated according to international standards, the method supports monitoring requirements of FSSAI, EU, Japan and APEDA.

Future Trends and Opportunities

Ongoing advances in ultra-fast chromatography and high-resolution mass spectrometry may further shorten analysis times and expand analyte coverage. Integration of automated sample preparation and enhanced data-processing algorithms, including retention time prediction and spectral library matching, will streamline method development. Broader databases for emerging contaminants and machine learning-driven quantification hold potential to improve accuracy and robustness in routine monitoring.

Conclusion

A streamlined QuEChERS extraction combined with Shimadzu’s LCMS-8045 and GCMS-TQ8040 NX platforms delivers a reliable, sensitive and high-throughput solution for quantifying over 300 pesticide residues in rice. The method meets international performance standards, offering laboratories a versatile protocol for routine quality control and regulatory compliance.

References

1. M. Anastassiades, S.J. Lehotay, D. Štajnbaher, F.J. Schenck, 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).
2. Guidance document on analytical quality control and method validation procedures for pesticide residues and analysis in food and feed, SANTE/12682/2019.