Detection and Quantification of Trace Levels of Carbaryl and Its Metabolites from Dendroctonus frontalis Zimmermann

A direct and sensitive high-performance liquid chromatographic (HPLC) method was developed for the detection and quantitative analysis of carbaryl and metabolites at the parts-per-billion level using a YMC stainless steel reversed-phase ODS (microBondapak C18) HPLC column (250 mm X 3.9 nm i.d.), equipped with a Waters Guard-Pak Cl8 precolumn module. The use of this methodology combined with radioisotopic technique is demonstrated by topically treating the southern pine beetle, Dendroctonus frontalis Zimmermann, with [naphthyl-1-14C]carbaryl and analyzing methanolic extracts of the exoskeleton, the vials in which beetles were held, and the whole body homogenates at various incubation time intervals after treatment. All extracts were passed through a Millex-HV 0.45-micrometers filter unit (Millipore, Bedford, MA) prior to HPLC analysis. Advantages of this method include high sensitivity, reproducibility, short analysis time, and good recovery. This HPLC method should be useful for toxicological and environmental studies that require the detection of nanogram concentrations of carbaryl and carbaryl metabolites