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

Importance of the Topic

Azo dyes and pesticide residues are common in textiles, leather, and traditional herbal formulations (churna). Their breakdown into carcinogenic aromatic amines and the presence of multi-class pesticides create significant health and regulatory concerns. Reliable, high-throughput analytical methods are essential to ensure consumer safety and compliance with international standards.

Study Objectives and Overview

This study developed and validated a rapid GC-MS/MS method for simultaneous screening, identification, and quantitation of up to 200 pesticide analytes and azo dye degradation products in Ayurvedic churna, leather, and textile samples. The method targets a 28-minute run time and conforms to EN ISO guidelines and EU regulatory limits.

Methodology and Instrumentation

Sample Preparation:

• QuEChERS extraction of powdered churna and textile samples using acetonitrile with 1% acetic acid, MgSO4, sodium acetate, and NaCl.
• Reduction of azo dyes to aromatic amines with sodium dithionite followed by t-butyl methyl ether extraction.
• Dispersive SPE cleanup with PSA and graphitized carbon black to minimize matrix effects.
• Centrifugation and direct injection of 3 μL extract into GC-MS/MS.

Used Instrumentation

• TriPlus RSH autosampler for automated sample handling.
• TRACE 1310 GC with programmable PTV injector and a 30 m × 0.25 mm × 0.25 μm TG-5 SilMS column.
• TSQ 8000 triple quadrupole GC-MS/MS operated in timed-SRM mode for sensitive and selective detection.
• TraceFinder software for method setup, retention time locking, quantitation, and automated QC checks.

Main Results and Discussion

The method achieved linear calibration (R² > 0.99) between 2.5 ng/g and 50 ng/g, recoveries of 70–120%, and RSDs < 20%. Timed-SRM enabled the screening of ~200 pesticides in a single 28-minute analysis without extensive segment optimization. Market sample testing detected chlorpyrifos ethyl and kresoxim methyl at 2.3 and 2.7 μg/kg, both below Unani guideline limits.

Applications and Practical Benefits

• High-throughput pesticide residue screening in herbal medicines and textile quality control.
• Compliance with EN ISO methods and EU regulations on azo dyes and pesticide levels.
• Efficient data processing and retention time synchronization for rapid decision-making.

Future Trends and Opportunities

Emerging GC-MS/MS enhancements and advanced software can further reduce analysis time and expand target lists. Integration with high-resolution mass spectrometry will support non-targeted screening of unknown contaminants. Portable sample preparation kits and miniaturized systems could enable on-site testing of textiles and herbal products.

Conclusion

The validated GC-MS/MS method offers rapid, sensitive, and selective multi-residue analysis of pesticides and azo dye cleavage products in complex matrices. Its high throughput, robust performance, and regulatory alignment make it ideal for routine quality control and compliance testing.

References

1. Narayanaswamy V. Origin and Development of Ayurveda. Anc. Sci. Life. 1981.
2. The Pesticides Compound Database. Thermo Fisher Scientific. 2013.
3. EN ISO 14362-1:2012. Textiles – Methods for determination of aromatic amines derived from azo colorants.