Analysis of Pesticide Residues in Apple Using Agilent Bond Elut QuEChERS AOAC Kits by GC/MS

Significance of the Topic

Rapid and reliable detection of pesticide residues in fruits is critical for food safety, regulatory compliance and consumer protection. The QuEChERS approach has transformed multiclass pesticide analysis by combining simplicity, cost-effectiveness and high throughput. This study evaluates Agilent Bond Elut QuEChERS AOAC kits for extraction and cleanup of 17 GC-amenable pesticides in apple, demonstrating a streamlined workflow suitable for routine laboratory use.

Objectives and Study Overview

The primary goal was to assess the performance of Agilent Bond Elut QuEChERS AOAC extraction and dispersive SPE kits for general fruits and vegetables in isolating volatile and semi-volatile pesticides from apple. Seventeen representative compounds spanning organochlorines, organophosphates, carbamates, phenols and pyrethroids were selected. The study compared two dispersive SPE formats (2 mL vs. 15 mL) and validated the method by GC/MS in SIM mode, focusing on recovery, precision and limits of quantitation relative to established maximum residue limits (MRLs).

Methodology and Instrumentation

Sample Preparation:

• Homogenize 15 g frozen apple cubes; spike with internal standard and pesticide mixes at 10, 50 and 200 ng/g.
• Add 15 mL acetonitrile (1% acetic acid), followed by Bond Elut AOAC extraction salt packet (MgSO₄/NaOAc); shake and centrifuge to partition.
• Transfer 1 mL or 8 mL supernatant to dispersive SPE tubes containing PSA and MgSO₄; vortex and centrifuge.
• Collect 500 µL cleaned extract for GC/MS analysis.

Instrumental Analysis:

• Gas chromatograph with HP-5MS column and splitless inlet.
• Mass spectrometer operated in selected ion monitoring (SIM) mode with retention time locking.
• Calibration from 10 to 400 ng/g (50–400 ng/g for Folpet) using matrix-matched standards and triphenyl phosphate as internal standard.

Instrumentation Used

• Agilent 7890 GC with 5975C MSD
• Agilent Bond Elut QuEChERS AOAC Extraction kit (p/n 5982-5755)
• Bond Elut QuEChERS dispersive SPE kits for general fruits and vegetables (p/n 5982-5022 and 5982-5058)
• Thermo IEC CentraCL3R centrifuge and Eppendorf microcentrifuge

Main Results and Discussion

Limits of Quantitation (LOQ) were 10 ng/g for most analytes and 50 ng/g for Folpet. Calibration exhibited excellent linearity (RSD of response factors <20%). Recoveries across 1 mL and 8 mL dispersive SPE formats averaged 90.8% and 94.2% respectively, with precision (RSD) of 5.7% and 4.3%. An interference near s-phenylphenol was observed but remained below 20% of the LOQ. Despite matrix co-extractives visible in blank chromato­grams, SIM mode provided adequate selectivity for accurate quantitation.

Benefits and Practical Applications

This QuEChERS-GC/MS workflow significantly reduces sample preparation time and solvent use while meeting stringent residue limits. High recoveries, consistent precision and sub-MRL sensitivity make it suitable for routine monitoring in food safety, QA/QC laboratories and regulatory testing. The parallel evaluation of two dispersive SPE volumes offers flexibility for different throughput requirements.

Future Trends and Opportunities

Integration with automated platforms and advanced detection techniques like GC-HRMS or complementary LC-MS/MS could expand the method’s scope to non-volatile or thermally labile pesticides. Development of novel sorbents for enhanced matrix removal and high-throughput robotics will further streamline multiclass residue analysis. Emerging regulatory demands for lower detection thresholds may drive refinements in sample cleanup and instrument sensitivity.

Conclusion

The Agilent Bond Elut QuEChERS AOAC extraction and dispersive SPE kits deliver a robust, fast and user-friendly method for GC/MS analysis of multiclass pesticide residues in apple. Excellent recoveries, precision and low LOQs confirm its suitability for compliance testing and routine food safety programs.

References

1. M. Anastassiades, S. J. Lehotay, Fast and Easy Multiresidue Method Using Acetonitrile Extraction/Partitioning and Dispersive Solid-Phase Extraction for the Determination of Pesticide Residues in Produce, J. AOAC Int., 2003, 86, 412-431.
2. S. J. Lehotay et al., Use of Buffering and Other Means to Improve Results of Problematic Pesticides in a Fast and Easy Method for Residue Analysis of Fruits and Vegetables, J. AOAC Int., 2005, 88, 615-629.
3. S. J. Lehotay et al., Determination of Pesticide Residues in Foods by Acetonitrile Extraction and Partitioning with Magnesium Sulfate, Collaborative Study, J. AOAC Int., 2007, 90, 485-520.
4. L. Zhao, D. Schultz, Evaluation of the QuEChERS AOAC Sample Preparation Kit for the Analysis of Pesticide Residues in Apples with LC/MS/MS Detection, Agilent Technologies publication 5990-3937EN.
5. P. L. Wylie, Screening for 926 Pesticides and Endocrine Disruptors by GC/MS with Deconvolution Reporting Software and a New Pesticide Library, Agilent Technologies publication 5989-5076EN.