Method Validation for Determining 513 Pesticide Residues in Cucumber Using LCMS-8060NX and 308 Residues by GCMS-TQ8040NX

Importance of the topic

Cucumbers are commonly consumed raw, retaining moisture and flavor but posing a risk for pesticide residue ingestion. Meeting regulatory maximum residue limits ensures food safety and consumer protection.

Objectives and overview

The validated method aims to quantify 513 pesticides by LC MS MS and 308 by GC MS MS in cucumber matrices, totalling 692 analytes. Method performance was assessed following SANTE 11312 guidelines using matrix-matched calibration and spiked quality controls.

Methodology

A modified QuEChERS approach was employed for extraction and cleanup. Key steps included

• Sample extraction with acetonitrile and salts (magnesium sulfate, sodium chloride, citrate salts)
• d-SPE cleanup using PSA and anhydrous magnesium sulfate
• Filtration through a 0.2 µm nylon filter
• Dilution of LC MS samples fivefold with LC MS grade water
• Spiking at 10, 20 and 50 µg/kg for LC MS MS and 10 and 20 µg/kg for GC MS MS in six replicates

Used instrumentation

• Shimadzu LCMS-8060NX with LC-40 series system and Shim-pack Velox Biphenyl column
• Shimadzu GCMS-TQ8040NX with SH-Rxi-5Sil MS capillary column
• Ionization modes: ESI positive/negative for LC MS MS and EI for GC MS MS
• LabSolutions Insight software for data processing

Main results and discussion

Calibration curves were linear from 1 to 75 µg/L for LC MS MS and 1 to 100 µg/L for GC MS MS with correlation coefficients above 0.99. Mean recoveries fell between 70 and 120 % with RSDr and RSDR below 20 % at LOQ levels. Some analytes showed lower recoveries but remained reproducible within accepted limits.

Benefits and practical applications

The combined LC MS MS and GC MS MS method offers comprehensive multi-residue screening in a single workflow. High-throughput analysis supports routine monitoring in food safety laboratories and regulatory compliance.

Future trends and potential applications

Advancements may include integration of high-resolution mass spectrometry for untargeted screening, further automation of sample preparation, expansion of compound libraries, and AI-driven data analysis to improve throughput and sensitivity.

Conclusion

The validated protocol delivers accurate and precise quantification of nearly 700 pesticides in cucumbers, complying with SANTE guidelines. It demonstrates robust recoveries and repeatability, making it suitable for routine food safety testing.

Reference

EN 15662 Determination of pesticide residues using GC MS and or LC MS MS following acetonitrile extraction partitioning and cleanup by dispersive SPE QuEChERS method 2007 European Committee for Standardization