Fourier transform infrared spectrometric determination of Ziram

A procedure has been developed for vapour-phase Fourier transform infrared determination of Ziram, a dithiocarbamate pesticide. The method is based on the evolution of CS2, after decomposition of the dithiocarbamate with diluted H2SO4 at 50°C. The CS2 evolved was swept by a carrier flow of nitrogen to a laboratory-made infrared gas cell of 39 mm pathlength and 490 μl volume. The signals were registered as a function of time. The area of peaks obtained from absorbance measurement in the wavenumber range between 1600 and 1450 cm−1 were interpolated in a calibration line established from Ziram standards treated in the same way as samples. The method provided an absolute limit of detection of 0.055 mg, a variation coefficient of the order of 6% for an analyte mass of 50 mg, and an analysis time of 3.5 min.