Method for the determination of 313 Residual Pesticides in Black tea using LCMS-8045 and GCMS-TQ8040 NX

Importance of the Topic

Tea is among the most consumed beverages worldwide and requires effective monitoring of pesticide residues to ensure food safety and compliance with international maximum residue limits. The complex tea matrix and broad spectrum of applied pesticides make sensitive and high-throughput multi residue methods indispensable for quality assurance and regulatory testing.

Objectives and Study Overview

This work presents a comprehensive analytical approach for simultaneous quantification of 313 pesticides in black tea. The method employs ultra fast LC MS MS and GC MS MS techniques to achieve low limits of quantification and enhanced sample throughput. The validation covers regulatory requirements under FSSAI, EU, APEDA and Japan guidelines.

Methodology and Instrumentation

The sample preparation is based on a modified QuEChERS extraction followed by cleanup using PSA, C 18, GCB and appropriate salts. Acidified organic solvents ensure efficient extraction of a wide range of analytes. Matrix matched calibration with weighted regression 1/C2 and external standards is used for quantification. Instrumental analysis is conducted on Shimadzu LCMS 8045 coupled with Nexera X2 and Shimadzu GCMS TQ8040 NX. Key operating conditions include:

• LC MS MS flow rate 0.4 mL/min, gradient run time 21 min, injection volume 10 µL, ESI source
• GC MS MS splitless injection of 1 µL, 25 min runtime, helium carrier, EI source

Main Results and Discussion

Validation parameters demonstrated high specificity, linearity, recovery and precision:

• System precision (RSDr) and reproducibility (RSDR) below 20% for the majority of compounds
• Calibration accuracy between 80 and 120% over 1–50 µg/L (LC) and 1–15 µg/L (GC)
• Mean recoveries of 70–120% at LOQ for most analytes; LOQs of 10 µg/kg achieved for 198 compounds by LC MS MS and 81 by GC MS MS

The shorter run times and lower flow rates extend column lifetime and improve assay stability over extended analyses.

Benefits and Practical Applications

The proposed method offers:

• Rapid multi residue screening suitable for high throughput testing laboratories
• Robust performance in complex tea matrices with minimized matrix interference
• Compliance with international regulatory standards for pesticide residues

Future Trends and Possibilities

Advancements may include integration of high resolution and orbitrap mass analyzers, further automation of sample preparation, expansion of pesticide libraries and application of data processing with machine learning to enhance selectivity and throughput.

Conclusion

A simple, sensitive and rapid multi residue procedure has been validated for 313 pesticides in black tea using ultra fast LC MS MS and GC MS MS. The method meets stringent regulatory guidelines, delivers reliable quantification at trace levels and supports efficient laboratory workflows.

References

1. M Anastassiades S J Lehotay D Stajnbaher F J Schenck Fast and Easy Multiresidue Method Employing Acetonitrile Extraction Partitioning and Dispersive Solid Phase Extraction for the Determination of Pesticide Residues in Produce J AOAC Int 86 412 431 2003
2. Guidance Document on Analytical Quality Control and Method Validation Procedures for Pesticide Residues Analysis in Food and Feed SANTE 12682 2019