ANALYSIS OF ORGANOPHOSPHORUS PESTICIDES IN VEGETABLE SAMPLES BY HOLLOW FIBER LIQUID PHASE MICROEXTRACTION COUPLED WITH GAS CHROMATOGRAPHY-ELECTRON CAPTURE DETECTION

Abstract

A method based on hollow fibre liquid phase microextraction (HF-LPME) coupled with gas chromatography electron capture detection (GC-ECD) has been developed for the determination of organophosphorus pesticides (OPPs) (chlorpyrifos and profenofos) in vegetable samples. In this method, a microsyringe needle with 1.5 cm polypropylene hollow fibre containing a volume of organic acceptor phase (n-dodecane) was immersed in an aqueous donor solution, and at the completion of extraction, the acceptor phase was withdrawn and transferred to GC-ECD for analysis. The effects of extraction solvent, volume of acceptor phase, and volume of donor phase were investigated. The optimized conditions for HF-LPME of the selected OPPs were n-dodecane as organic solvent, 11 mL of donor phase, and 3 μL of acceptor phase. The correlation coefficient (r²) of the calibration curves ranged from 0.998 to 0.999. The limits of detection (LOD) were between 0.099 and 0.128 μg/mL. The developed method provided excellent RSDs ranging from 0.54% to 8.00% and analyte recoveries ranging from 60.8% to 88.0%. This method was applied successfully for determination of organophosphorus pesticides in selected vegetables.

Keywords:

• GC-ECD
• hollow-fiber liquid phase microextraction
• organophosphorus pesticides

ACKNOWLEDGMENTS

The authors are grateful to Universiti Teknologi Malaysia for the facilities and Ministry of Science, Technology and Innovation (MOSTI), and the Ministry of Higher Education (MOHE) Malaysia for financial supports vote number 79079 and 78084.