The Malaysian Journal of Analytical Sciences Vol 12 No 1 (2008): 105 – 110

 

 

COMPARATIVE STUDY ON CLEANUP PROCEDURES FOR THE DETERMINATION OF ORGANOPHOSPHORUS PESTICIDES IN VEGETABLES

 

Alvin Chai Lian Kuet¹  and Lau Seng²

 

¹Agriculture Research Centre, Semongok, Kuching, Sarawak

²Universiti Malaysia Sarawak, 94300 Kota Samarahan, Sarawak

 

Abstract

A  study  was  carried  out  to  compare  the  cleanup  procedures  for  the  determination  of  organophosphorus  pesticides  in vegetables. Eleven organophosphorus pesticides were extracted with acetone and methylene chloride. Extracts were cleanup by solid-phase extraction (SPE) mixed-mode column using quaternary amine and aminopropyl (SAX/NH₂) or octadecyl (C₁₈) sorbents. The pesticides were determined by gas chromatography with flame photometric  detector. The recovery results obtained from the SPE SAX/NH₂   and C₁₈  cleanups in carrot, cucumber and green mustard samples were in the range of 71.0 %  to 115 %. Lower recoveries were obtained for polar pesticides, methamidophos and dimethoate. These  results were compared to the method currently used in the laboratory which does not include any cleanup.

 

Key words: Solid-phase extraction, organophosphorus pesticides, gas chromatography

 

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