Analysis of pyrethroid insecticides in Chironomus dilutus using matrix solid phase dispersion extraction.

A matrix solid phase dispersion method was developed to detect eight pyrethroid insecticides in the aquatic invertebrate, Chironomus dilutus. A mixture of silica gel, diatomaceous earth and primary/secondary amino solid absorbents were selected as the dispersion matrix, while 7% ethyl ether in hexane was used as the elution solvent. Method detection limits for the target pyrethroids ranged from 0.46 to 4.4 microg kg(-1), and recoveries were 63.5%-124.0%, 43.7%-116.0% and 53.1%-93.1% at spiked levels of 5, 20 and 50 microg kg(-1), respectively. The developed method was used to assess pyrethroid residues in laboratory-exposed and field-collected C. dilutus.