Determination of Residues of Carbamates and Their Metabolites in Ginger by Ultra-High Performance Liquid Chromatography–Tandem Mass Spectrometry

Significance of the Topic

Monitoring carbamate pesticides and their metabolites in ginger is critical due to the high toxicity of some parent compounds and their oxidative products. Regulatory bodies in the EU, Japan, and China have set stringent residue limits to protect consumers. The complex matrix of ginger, rich in oils and phenolic compounds, poses analytical challenges that demand robust cleanup and sensitive detection techniques.

Objectives and Study Overview

This study aimed to develop and validate a rapid, sensitive, and reliable method for simultaneous quantitation of 26 carbamate pesticides and key metabolites in ginger. The approach integrates a simple extraction and cleanup protocol with ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) and employs matrix-matched calibration to address matrix effects.

Methodology and Instrumentation

Sample preparation involved:

• Weighing 10 g of minced ginger and extracting with 20 mL acetonitrile and 2 g NaCl.
• Centrifugation and liquid-liquid partition, followed by nitrogen evaporation and redissolution in dichloromethane:hexane.
• Cleanup using an aminopropyl (NH2) solid-phase extraction column, with sequential wash and elution steps to remove co-extracted interferences.
• Final reconstitution in acetonitrile:water (1:1) prior to UHPLC-MS/MS analysis.

Instrumentation Used

• UHPLC: Agilent 1290 Infinity system with a ZORBAX Eclipse Plus C18 RRHT (100 × 2.1 mm, 1.8 µm) column at 30 °C.
• Mobile phases: 5 mM ammonium formate/0.02% formic acid in water (A) and acetonitrile (B) under a 9.5 min gradient.
• MS/MS: Agilent 6460 triple quadrupole with Jet Stream ESI in positive MRM mode.

Main Results and Discussion

The method exhibited excellent linearity (R2 > 0.99) over 0.20–500 µg/L. Limits of detection ranged from 0.05 to 2.0 µg/kg and limits of quantitation from 0.20 to 5.0 µg/kg. Recovery studies at spiking levels of 10, 30, and 100 µg/kg yielded recoveries between 70.9% and 119% with RSDs of 1.0%–11%. Analysis of 15 commercial ginger samples detected carbofuran and its 3-hydroxy metabolite in one sample and aldicarb sulfone in another, demonstrating real-world applicability.

Benefits and Practical Applications

This approach combines high throughput (10 min per run) with robust cleanup and sensitive detection, fulfilling regulatory requirements for trace analysis of carbamate residues in ginger. It can be implemented in food safety labs for routine screening and compliance testing.

Future Trends and Applications

Emerging trends include the extension of this workflow to other challenging matrices, integration of automated sample preparation, and adoption of high-resolution mass spectrometry for non-target screening. Advances in mixed-mode SPE sorbents and miniaturized UHPLC columns may further improve sensitivity and throughput.

Conclusion

An effective UHPLC-MS/MS method with NH2-SPE cleanup has been established for simultaneous determination of 26 carbamates and metabolites in ginger. The protocol delivers high sensitivity, accuracy, and precision, meeting global regulatory demands and supporting food safety monitoring.

References

1. He H. et al. J. Instrum. Anal. 33(2), 197–202 (2014).
2. EU Pesticide Database. http://ec.europa.eu/sanco_pesticides.
3. Japan Food Chemical Research Foundation. http://www.ffcr.or.jp.
4. China National Food Safety Standard GB 2763-2014 (2014).