Spectroscopic Analysis of Organophosphorus Pesticides Using Colorimetric Reactions

The UV-Vis and infrared (IR)absorption spectra of organophosphorus (OP)pesticides have been studied.A correlation in spectra was developed to optimize the OP pesticides in the environments.The spec-troscopic (UV-Vis and IR)spectrum of OP pesticides like methyl parathion,malathion and parathion has been interpreted in detail.A complete calculation of the normal frequencies and absolute intensities of UV-Vis and IR absorption bands are interpreted with the help of corresponding experimental data.In the colorimetric reac-tions,the bands appear at 2 077,1 637,1 455,1 015,655 cm-1 for malathion;2 081,1 639,1 316,1 015, 794,683 cm-1 for parathion;2 078,1 632,1 032,794 cm-1 for methyl parathion were used for quantitative or qualitative analysis.All these IR spectra were acquired by averaging 100 scans at a resolution of 4 cm-1 .It is determined experimentally in the region 200~450 nm for UV-Vis absorption bands and in the region 400~4 000 cm-1 for IR absorption bands.It is concluded that the mainly optically active groups (P—OH, C—O, P—O, C—O—C,P—O—C, P—S, —OH)present in pesticides which are responsible in change in sig-nificant data for quantitative and qualitative analysis.The various optical properties like wavelength,band en-ergy,wave number,and frequency,also are calculated.