Determination of bentazone in waters by solid-phase spectrofluorimetry

A sensitive method for determining trace amounts of bentazone was developed. The method is based on solid-phase spectrofluorimetry. Bentazone was fixed on a dextran-type anion-exchange gel, and the fluorescence of the gel, packed in a 1 mm thick quartz cell, was measured directly at an excitation wavelength of 338 nm and an emission wavelength of 436 nm by using a solid-phase attachment, The applicable concentration range was 2.0-120.0 mu g/L, with a detection limit of 0.4 mu g/L. The relative standard deviation at the 30.0 mu g/L level was 1.2%. The method was used to determine bentazone in natural water samples. Recoveries were 96.0-102.5%.