This paper reports a sensitive, simple and rapid flow injection chemiluminescence method for the determination of thiosemicarbazyl compounds in insecticides. It was found that the thiosemicarbazyl compounds have the tendency to inhibit the Chemiluminescent (CL) signal generated by KMnO4 – Na2SO3 system in the acidic medium. The linear correlation between the generated CL and the concentration logarithm was detected in the range of 7.3 × 10–9 – 5.4 × 10–7 M for Thiosemicarbazide (TSC) and 6.8 × 10-–9 – 3.6 × 10–7 M for the thiosemicarbazone; with the relative standard deviation (for 12 measurements) of 2.3% and 2.6% respectively. The limits of detection (3s) are 2.2 × 10–10 M and 1.8 × 10–10 M respectively. The sample throughput is 100 samples/h. The proposed method was used to determine the TSC in the synthetic samples with satisfactory results. To prove the practical use of the method, it was applied to determine the TSC and thiosemicarbazone concentrations in insecticides purchased in the market.

During the past few years, Thiosemicarbazide (TSC), along with its derivatives, has attracted more attention due to its several uses in analytical chemistry, biotechnology, agriculture, and medical drugs. In fact their chelating properties enable them to be used in the complexometric and spectrophotometric analysis of some metals (Narayana and Gajendragad, 1987; and Parikh et al., 2009). In the clinical laboratories, TSC is used to perform the di-acetyl method for urea determination in the biological fluids (Mather and Roland, 1969). In agriculture, it is used as an ingredient in fertilizers, herbicides and insecticides (Tsao et al., 2003; and Wang et al., 2010).

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