Comparison of two vibrational procedures for the direct determination of mancozeb in agrochemicals

The direct determination of mancozeb in agrochemicals has been made by diamond attenuated total reflectance (ATR) Fourier transform infrared spectroscopy in the middle range (DATR-MIR) and diffuse reflectance infrared Fourier transform spectroscopy in the near range (DR-NIR) methods using in both cases a previous identification of the samples using a dendrographic classification and an appropriate partial least squares (PLS) calibration established from a set of nine external standards and optimized for each type of sample. It was analyzed a heterogeneous population of 11 samples obtained from the Spanish market, containing different co-formulated products, such as fosetyl-Al, copper oxychloride, metalaxyl or cymoxanil. High performance liquid chromatography (HPLC) was used as reference method for validation of both vibrational strategies. The close agreement between values found for both, DATR-MIR and DR-NIR methods, and reference HPLC values indicates the accuracy and reliability of the proposed techniques for the direct determination of mancozeb in commercially available formulations.