Abstract
A method for the determination of allethrin and other pesticides in mosquito coils was developed by the combination of shaking extraction and gas chromatography (GC). Allethrin and other pesticides were adequately extracted by shaking for only half an hour with a mixture of toluene and 99% formic acid (5:1). This shaking extraction method was more effective for shortening the extraction time compared with the Soxhlet extraction method, and accurate determination was achieved without the interference from inert materials in the mosquito coils. The recovery of allethrin in various contents from the coils was 96.6 to 97.1%, with a 1.2 to 1.5% coefficient of variation. Furthermore, the recoveries of other pesticides and synergists from the coils were 94 to 102% by this shaking extraction method.