Quantitative Analysis of 15 Carbamates in Vegetables Using DisQuE Cleanup and UHPLC with Mass Detection

Significance of the topic

Carbamate pesticides play a critical role in crop protection and are subject to stringent regulatory limits due to potential health risks. Rapid and reliable analytical methods are essential for monitoring residues in vegetables and ensuring food safety.

Objectives and study overview

This work evaluates an efficient and cost-effective UHPLC-MS approach for quantifying 15 carbamate pesticides in vegetable matrices. Key aims include:

• Simplifying sample preparation by eliminating derivatization.
• Implementing a single-quadrupole mass detector to meet or exceed the Chinese GB standard (NY/T-761 2008).
• Demonstrating method performance in common vegetables (corn powder, cabbage, tomato).

Methodology and instrumentation

Samples (15 g) were extracted with acidified acetonitrile, cleaned using DisQuE QuEChERS dSPE pouches, and analyzed by dilution and injection. Separation was achieved on a CORTECS T3 column (2.7 µm, 3 × 150 mm) at 40 °C with a water/methanol gradient containing 0.1% formic acid and 2 mM ammonium formate. The ACQUITY QDa detector in ESI+ mode monitored selected ions with optimized cone voltages for each analyte.

Used Instrumentation

• ACQUITY Arc UHPLC System
• ACQUITY QDa Mass Detector
• CORTECS T3 Column (2.7 µm, 3 × 150 mm)
• DisQuE QuEChERS dSPE Pouches

Key results and discussion

Calibration curves for all 15 analytes were linear from 1 to 100 µg/L (R² > 0.998). Matrix effects in corn powder, cabbage, and tomato ranged from –74% to +19%, effectively compensated by matrix-matched calibration. Recoveries at 5, 10, and 20 µg/kg spikes varied between 72% and 112% with RSDs below 15%. A representative chromatogram at 5 µg/kg in corn powder showed clear peak separation and low background interference.

Benefits and practical applications

The dilute-and-shoot protocol eliminates time-consuming derivatization, reducing analysis time and solvent consumption. The single-quadrupole mass detector provides adequate sensitivity for routine compliance testing at regulatory limits, offering a cost-effective alternative to MS/MS systems.

Future trends and potential applications

Automation of the QuEChERS workflow could further increase sample throughput. Integration with high-resolution or tandem mass spectrometry would expand detection scope and lower limits of quantitation. Emerging miniaturized sample preparation and portable mass detectors offer potential for on-site monitoring.

Conclusion

The proposed UHPLC-QDa method delivers a robust, efficient, and economical solution for quantifying 15 carbamate pesticides in vegetables. It meets Chinese regulatory standards while streamlining laboratory operations.

References

• NY/T-761 2008 Pesticide multiresidue screening methods for the determination of organophosphorus, organochlorine, pyrethroid and carbamate pesticides in vegetables and fruits
• AOAC Official Method 2007.01 Pesticide residues in foods by acetonitrile extraction and partitioning with magnesium sulfate using GC–MS and LC–MS/MS
• CEN Standard Method 15662:2008 Foods of plant origin – Determination of pesticide residues using GC-MS and/or LC-MS/MS following acetonitrile extraction/partitioning and dispersive SPE cleanup