Rapid Fluorospectrophotometric Determination of Residual Amount of Phoxim

In a phosphate buffer of pH 6.6,the fluorescence intensity of titan yellow (TY) was enhanced by its reaction with definite amount of Tween-80.But when microamounts of the insecticide phoxim was added to this reaction system,significant decrease in fluorescence intensity was observed as measured at the wavelengths of 412 nm (λex) and 460 nm (λem).Linear relationship between the magnitude of decrease in fluorescence intensity and the mass concentration of phoxim was obtained in the range within 0.72 mg·L-1.Detection limit (3S/N) found for this reaction system was 0.031 mg·L-1.Based on these facts,a rapid method for determination of residual amounts of phoxim by fluorospectrophometry was proposed,and applied to the analysis of samples of millet and soil.Values of average recovery found were 93.5% and 97.7%,and values of RSD′s (n=5) were 1.7% and 2.6% respectively.