Comparison of extraction methods for DDT residue detection in soil : A dissertation submitted in partial fulfilment of the requirements for the degree of Diploma of Applied Science in Lincoln University

Abstract

The extraction process is an important step in determination of pesticide residues in that substances which are not extracted are not measured. In this study, the efficiency of recovery of DDT residues in soil of two extraction methods, tumble and ultrasonic methods, were studied and compared, together with three different soil moisture levels. It was found that the ultrasonic method was better because it was easy, fast and used less solvent but gave equal recovery to the tumble method. Soil moisture levels were also found to have an important influence on the efficiency of extraction. In this experiment, the field moist soil gave the best recovery and dried soil the lowest while the rewetted soil gave moderate recovery.