Confirmation of Pesticide Residue Identity: Part IX Organophosphorus Pesticides

Abstract

This paper describes a confirmation procedure for residue levels of dyfonate, dichlorofenthion and cyanox. After extraction and quantitation by flame photometric detector (FPD) - gas liquid chromatography (GLC), the organophosphorus pesticides are hydrolyzed in a 10% methanolic-potassium hydroxide solution. The phenolic hydrolysis products are then extracted from this solution and reacted with pentafluorobenzyl bromide to produce the pentafluorobenzyl (PFB) ether derivatives. These PFB ethers are subsequently cleaned-up and fractionated on a silica gel micro-column and analyzed by electron capture (EC) - GLC.

The chromatographic results of five other organophosphorus pesticides and five N-methyl carbamates, which are also analyzed by this method, are presented.

As low as 0.01 ug dyfonate and dichlorofenthion and 0.10 ug cyanox from a one liter water sample can be confirmed.

Key Words:

• Confirmation
• Organophosphorus
• Pesticide
• Hydrolysis
• Pentafluorobenzyl bromide