DETERMINATION OF PESTICIDE RESIDUES IN RICE-BASED BABY FOOD USING GC-MS/MS WITH APGC™ AFTER EXTRACTION AND CLEAN UP USING QUECHERS

Importance of the Topic

The monitoring of pesticide residues in rice-based baby food is critical to ensure infant health and regulatory compliance. Infants and young children are more vulnerable to toxic effects due to their lower body weight and developing systems. Regulatory bodies in the EU have set stringent maximum residue levels (MRLs), often far below general food limits, to apply the precautionary principle and reduce chronic exposure risks.

Objectives and Study Overview

This study aimed to validate a high-sensitivity analytical method for the determination of 166 pesticides and metabolites in rice-based baby food at concentrations well below regulatory thresholds (down to 0.0003 mg/kg). The goal was to demonstrate compliance with Commission Directive 2006/125/EC and Delegated Regulation (EU) 2021/1041, using GC-MS/MS combined with atmospheric pressure gas chromatography (APGC™) and a simplified QuEChERS extraction.

Methodology

Sample preparation followed a QuEChERS protocol:

• Hydration of 5 g of sample followed by extraction with acetonitrile.
• Salt addition (MgSO₄, NaCl, citrate salts) and centrifugation.
• Freezing of extract to enhance cleanup, followed by dispersive SPE with MgSO₄ and PSA.
• Acidification, dilution 1:1 with acetonitrile, and direct injection into GC-MS/MS.

Two spiking levels (0.0005 and 0.001 mg/kg) were tested in quintuplicate to assess method performance.

Instrument Used

GC-MS/MS analysis employed a Waters Xevo TQ-XS system coupled with APGC 2.0. Key parameters included:

• Source temperature: 150 °C; transfer line: 280 °C.
• Corona current: 2.0 µA; auxiliary gas flow: 200 L/h; cone gas flow: 265 L/h.
• Water as a modifier for soft ionization, enhancing sensitivity.

Key Results and Discussion

The method demonstrated instrument LODs of ≤0.0003 mg/kg for 165 of 166 analytes; thiometon LOD was 0.005 mg/kg. Calibration at 0.3 µg/kg showed 96% of compounds met ±20% residual tolerance and r²>0.98. Recovery studies at 0.0005 mg/kg achieved 90% of pesticides within 70–120%, rising to 92% at 0.001 mg/kg. Repeatability (RSDr) was ≤20% for 96% of analytes at the lower level and 100% at the higher level. Ion ratio and retention time criteria were met for over 94% of compounds.

Benefits and Practical Applications

The validated method offers:

• High throughput with minimal solvent exchange and no large-volume injections.
• Robust compliance testing at sub-MRL levels for infant food products.
• Applicability in quality control, regulatory monitoring, and research laboratories.

Future Trends and Potential Applications

Emerging directions include the integration of high-resolution mass spectrometry for non-target screening, automation of sample preparation, green solvent substitution in QuEChERS, and expansion to other infant food matrices. Advanced data analytics and AI-driven workflows may further streamline multi-residue pesticide analysis.

Conclusion

The presented GC-MS/MS with APGC and QuEChERS protocol reliably detects and quantifies 166 pesticides in rice-based baby food at trace levels, fulfilling stringent EU regulatory requirements with excellent sensitivity, accuracy, and precision.

References

• Commission Directive 2006/125/EC of 5 December 2006 on processed cereal-based foods and baby foods for infants and young children. OJ L 339, 6.12.2006, p. 16–35.
• Commission Delegated Regulation (EU) 2021/1041 of 16 April 2021 amending Delegated Regulation (EU) 2016/127 as regards pesticides in infant formula and follow-on formula. OJ L 225, 25.6.2021, p. 4–6.
• EURL-CF Validation Report 31A. Determination of pesticide residues in rice-based baby food by LC-MS/MS and GC-MS/MS (QuEChERS method), 2019.
• SANTE/11313/2021 Guidance Document on Analytical Quality Control and Method Validation Procedures for Pesticide Residues Analysis in Food and Feed, 2019.