Analysis of Multi-Residue Pesticides Present in Ayurvedic Churna by GC-MS/MS

Significance of the Topic

A precise and efficient multi-residue analysis of pesticides and colorants in traditional herbal powders (churna), textiles and leather is critical for consumer safety and regulatory compliance. Improper control of residues from pesticides and potentially carcinogenic azo dyes poses health risks, including dermal absorption and ingestion, especially in products used daily.

Objectives and Study Overview

This study aimed to develop a rapid, sensitive and robust GC-MS/MS method capable of screening and quantifying over 200 pesticide residues, as well as identifying azo dye breakdown products, in complex matrices such as Ayurvedic churna, natural and synthetic textiles, and leather.

Methodology and Instrumentation

Sample preparation employed a modified QuEChERS protocol: acetonitrile extraction with acidification, salt partitioning, dispersive SPE cleanup and, for azo dyes, reductive cleavage to aromatic amines followed by liquid–liquid extraction. Chromatographic separation used a programmable temperature vaporization injector and a low-bleed GC column. Detection relied on timed-SRM acquisition on a triple quadrupole mass spectrometer. Key steps included:

• Extraction of 15 g sample with acetonitrile (1% acetic acid), MgSO₄, NaOAc, NaCl
• Cleanup by PSA and GCB dispersive SPE
• Centrifugation, concentration and reconstitution for GC-MS/MS
• GC-MS/MS analysis with synchronized retention-time windows

Main Results and Discussion

The method achieved linear calibration (R²>0.99) for all target compounds over 2.5–50 ng/g. Recoveries ranged from 70% to 120% with relative standard deviations below 20%. A full screening of market samples detected chlorpyrifos ethyl and kresoxim methyl at 2.3 and 2.7 µg/kg, respectively—levels below established limits.

Benefits and Practical Applications

• High throughput: 28 min per run for over 200 analytes
• Strong selectivity and sensitivity down to low ng/g levels
• Compliance with EN ISO standards for textiles and leather
• Applicable to quality control in herbal product manufacturing and textile/leather processing

Future Trends and Applications

Advances may include integration of high-resolution mass spectrometry for non-target screening, miniaturized sample preparation techniques, automation of data processing with machine learning for spectral deconvolution, and expansion to new classes of emerging contaminants in traditional medicines and consumer materials.

Conclusion

The validated GC-MS/MS workflow combining QuEChERS extraction, timed-SRM acquisition and automated data processing offers reliable multi-residue pesticide analysis and azo dye identification in challenging matrices. Its speed, robustness and compliance with international standards make it suitable for routine regulatory and quality-assurance laboratories.

Instrumentation

• Thermo Scientific TriPlus RSH autosampler
• Thermo Scientific TRACE 1300 GC with PTV injector
• Thermo Scientific TSQ 8000 triple quadrupole GC-MS/MS
• TraceFinder software for data acquisition and processing

References

• Narayanaswamy V., Origin and Development of Ayurveda (A Brief History), Ancient Science of Life, 1981, 1(1):1–7.
• Thermo Fisher Scientific, The Pesticides Compound Database, Austin, TX, USA, 2013.
• Government of India, Department of AYUSH, Protocol for Testing Guidelines for Ayurvedic, Siddha and Unani Medicines, Pharmacopoeial Laboratory for Indian Medicines, Ghaziabad (Chapter 2.5.1).