Determination of carbaryl in foods by solid-phase room-temperature phosphorimetry

A phosphorimetric solid phase assay is pro- posed for the determination of the pesticide carbaryl (CBL) at room temperature. CBL was spotted on filter pa- per together with Tl(I) as heavy metal, and dried for 3 min, after which the diffuse transmitted phosphores- cence was measured using two quartz plates to avoid the quenching effect produced by atmospheric oxygen. The linear dynamic range was 0.5-4.0 μg/mL and the detec- tion and quantification limits were 0.09 and 0.31 μg/mL, respectively. The precision of the method, expressed as relative standard deviation, was 2.3% for a sample con- taining 2.0 μg/mL of CBL. The method was applied to the determination of CBL residues in cereals, potatoes and waters, obtaining recoveries ranging between 92 and 105%.