Determination of Trace Amounts of Carbaryl in Water by Solid Phase Spectrofluorimetry

A simple and sensitive spectrofluorimetric method for the determination of carbaryl residues in water is presented. Carbaryl is hydrolized in alkaline medium to 1-naphthol. This hydrolysis product is fixed on QAE Sephadex A-25 gel at pH 11.20. The fluorescence of the gel, packed in a 1 mm silica cell, was measured directly using a solid-surface attachment. Spectral characteristics of 1-naphthol-gel system are described in detail. The applicable concentration range was 0.5–60.0 ng.ml−1, with a relative standard deviation of 0.9% and a detection limit of 0.1 ng.ml−1. The method was applied to the determination of carbaryl in natural waters.