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

Significance of the Topic

A robust analytical approach for detecting trace level contaminants in complex herbal and textile matrices is critical for consumer safety and regulatory compliance. Ayurvedic powders often contain residual pesticides from raw herbs, while certain azo dyes used in textiles and leather can produce carcinogenic aromatic amines. Rapid, sensitive, and high throughput methods are therefore vital to monitor and control these substances.

Objectives and Overview of the Studies

Two complementary application studies are presented:

• Development of a multi residue pesticide screening and quantitation method in ayurvedic churna using QuEChERS extraction followed by GC MS MS on a triple quadrupole system.
• Establishment of a GC MS full scan protocol for detection, identification, and quantitation of azo dyes and their aromatic amine cleavage products in textiles and leather according to EN ISO standards.

Methodology and Instrumentation

Sample Preparation for Pesticide Analysis

• QuEChERS extraction of 15 g powdered churna with acidified acetonitrile and salts.
• Dispersive SPE cleanup with PSA and GCB.
• Calibration using multi point curves from 2.5 to 50 ng g with matrix matched standards.

Sample Preparation for Azo Dye Analysis

• Reduction of accessible azo dyes on cellulose and protein textiles with sodium dithionite followed by SPE.
• Liquid liquid extraction of dyes from synthetic fabrics and leather with MTBE after reduction.

Instrumentation

• TriPlus RSH autosampler and TRACE 1300 GC coupled to TSQ 8000 GC MS MS in timed SRM mode controlled by TraceFinder software for pesticide screening of about 200 compounds in a 28 minute run.
• ISQ Series GC MS operating in fast full scan mode with library search for mass spectral identification and compound specific ion quantitation for azo dyes and derived aromatic amines.

Main Results and Discussion

Pesticide Analysis

• Excellent linearity with correlation coefficients above 0.99.
• Recoveries between 70 and 120 percent with relative standard deviations below 20 percent.
• Limit of quantitation at 2.5 ng g enabling detection of chlorpyrifos ethyl and kresoxim methyl at 2.3 and 2.7 µg kg in market samples below regulatory thresholds.

Azo Dye Analysis

• High sensitivity full scan spectra allowed unambiguous library based identification of dyes and confirmation of positive findings.
• Quantitation on fragment ions demonstrated compliance with EN ISO 14362-1 criteria for direct accessible azo colorants.
• Rapid acquisition rates yielded narrow peaks and excellent chromatographic resolution for complex dye mixtures.

Benefits and Practical Applications

The described methods deliver high throughput workflows with minimal sample preparation. They provide the selectivity needed to analyze complex matrices such as herbal churna and dyed fabrics with high natural matrix load. Laboratories can achieve reliable quantitation and confirmation to support quality control in phytopharmaceutical production and textile safety testing.

Future Trends and Potential Applications

Advances in high resolution mass spectrometry and automated sample handling will further enhance sensitivity and reduce analysis time. Expansion of compound libraries and the use of machine learning for spectral deconvolution promise improved screening of emerging contaminants. Miniaturized and portable GC MS devices could enable on site testing in manufacturing facilities and field laboratories.

Conclusion

Fast and sensitive GC MS based methods were established for monitoring pesticide residues in ayurvedic powders and azo dye contaminants in textiles and leather. The combination of QuEChERS extraction, timed SRM on a triple quadrupole system, and rapid full scan detection ensures high selectivity, robustness, and compliance with international standards. These protocols support efficient quality assurance in herbal medicine and textile industries.

Reference

• Narayanaswamy V Origin and Development of Ayurveda (A Brief History) Anc Sci Life 1981 1 1 1 7
• The Pesticides Compound Database Thermo Fisher Scientific Austin TX USA 2013
• Government of India Department of AYUSH Protocol for testing guideline for Ayurvedic Siddha and Unani medicines Chapter 2.5.1 Pharmacopoeial Laboratory for Indian Medicines 2013
• European Commission Scientific Committees Opinion Brussels 18 January 1999
• Directive 2002/61/EC of the European Parliament and of the Council of 19 July 2002
• EN ISO 14362-1 Textiles Methods for the determination of certain aromatic amines derived from azo colourants Part 1