FT-Raman spectrometry determination of Malathion in pesticide formulations

A fast and environmentally friendly method has been developed for Fourier transform-Raman (FT-Raman) spectrometry determination of Malathion in pesticide emulsifiable concentrate formulations. The method is based on the measurement of intensity peak height values at 1737 cm⁻¹ Raman shift corrected using a baseline defined at 1900 cm⁻¹. Samples were diluted with CHCl₃ and the FT-Raman spectra collected in back-scattering mode over 3.3 min at a nominal resolution of 4 cm⁻¹ accumulating 50 scans per spectra and using a laser power of 1250 mW. The developed procedure provided a limit of detection of 1.8% w/w in the original sample. Results found by FT-Raman spectrometry were statistically comparable with those obtained by flow injection Fourier transform infrared spectrometry, FIA-FTIR, and gas chromatography (GC) and were in good agreement with those reported by the manufacturer. The FT-Raman developed procedure reduces drastically the chlorinated solvent waste generation and avoids the contact of the operator with toxic products, being a fast alternative to the CIPAC recommended GC procedure.