ABSTRACT
Chlorophenoxy acids are one of the most important classes of chlorinated herbicides. In these compounds, chlorosubstituted benzene rings are attached to lower carboxylic acids via an oxygen atom. This chapter lists some of the common chlorophenoxy acid herbicides. The method of analysis primarily involves four basic steps: extraction of herbicides from the sample into an organic solvent, hydrolysis of the extract, esterification, and gas chromatographic (GC) determination of the herbicide esters formed. Aqueous samples are extracted with diethyl ether while soils, sediments, and solid wastes are extracted with acetone and diethyl ether. Herbicide acids extracted into the ether are hydrolyzed with KOH and water. Chlorophenoxy acids after being extracted out from the sample matrix, separated from organic interferences, and concentrated down into a small volume of ether are now converted into their methyl esters. GC using an electron capture detector (ECD) analyzes the methyl esters of herbicides.
