Conditions for solid-phase extraction of agricultural chemicals in waters by using n-octanol–water partition coefficients

Abstract

The solid-phase extraction behaviour of 25 aromatic compounds and 20 agricultural chemicals was investigated in a reversed-phase system using eight Sep-Pak cartridges. The recovery was related closely to their n-octanol–water partition coefficients. Those compounds with high coefficients were easily sorbed, but were difficult to elute. The extent of elution could be improved by adding methanol to the sample solution. The results suggest that the most important solid-phase extraction conditions for enrichment and separation can be selected approximately by using the partition coefficient as a key parameter. The influences of humic acid and surfactants on the recovery were also studied. Suggested guidelines for efficient enrichment and separation by solid-phase extraction are presented. Some applications were tested and good results were obtained.