Multiresidue analysis of pesticides in Turmeric (Curcuma longa) powder by GCMS/MS using QuEChERS’ extraction method

Importance of the Topic

Turmeric powder is a staple spice in food, cosmetics and traditional medicines, often cultivated with extensive pesticide use. Monitoring residue levels ensures consumer safety, regulatory compliance and maintains product quality across global markets.

Objectives and Study Overview

This study aimed to develop and validate a robust, multiresidue analytical method for quantifying over 60 pesticides in commercially available turmeric powder. Key goals included achieving low limits of quantification (LOQs) below EU maximum residue limits (MRLs), ensuring high accuracy and precision, and demonstrating applicability for routine quality control.

Methodology and Instrumentation

The analytical workflow combined a modified AOAC QuEChERS extraction with gas chromatography tandem mass spectrometry (GC-MS/MS) using a Shimadzu GCMS-TQ8040 NX triple quadrupole system. Main steps included:

• Sample extraction: 2 g turmeric spiked for recovery, hydrated with water, extracted with acidified acetonitrile, and partitioned with QuEChERS salts.
• CLEANUP: Dispersive SPE using MgSO4, PSA, C18 and GCB to remove matrix interferences.
• Concentration and reconstitution: Evaporation of supernatant and final dilution in hexane/ethyl acetate for injection.
• GC conditions: SH-Rxi™-5Sil MS column, splitless injection, helium carrier, 50 min temperature program.
• MS/MS conditions: Electron ionization, MRM acquisition with two transitions per analyte, optimized dwell times via Smart Pesticide Database.

Main Results and Discussion

No target pesticides were detected in blank turmeric extracts. Calibration curves prepared in matrix exhibited linearity (r2 > 0.985) across 5–50 ppb. Method precision at LOQ (10 ppb) showed %RSD < 20% and recoveries ranged from 70% to 120% for all compounds. LOQs met or were lower than EU-MRLs for turmeric, confirming method sensitivity and suitability.

Benefits and Practical Applications

The validated protocol delivers:

• Comprehensive screening of multiple pesticide classes in a single run.
• High throughput via automated MRM method creation and optimized dwell times.
• Reliable quantification at trace levels compatible with regulatory limits.

Applications include routine quality control in spice production, regulatory monitoring and research on pesticide exposure.

Future Trends and Opportunities

Emerging directions may involve:

• Expansion of pesticide databases for automated method updates.
• Integration with high-resolution mass spectrometry for non-target screening.
• Miniaturized or field-deployable extraction techniques to streamline sample preparation.

Conclusion

The QuEChERS-GC-MS/MS approach on the Shimadzu TQ8040 NX platform offers a sensitive, accurate and efficient solution for multiresidue pesticide analysis in turmeric powder. It ensures compliance with international MRLs and supports high-throughput workflows in analytical laboratories.

Reference

No specific literature references were provided in the original text.