Towards minimization of chlorinated solvents consume in Fourier transform infrared spectroscopy determination of Propamocarb in pesticide formulations

A method has been developed for Fourier transform infrared (FTIR) spectroscopy determination of Propamocarb in emulsifiable pesticide concentrate formulations. Five microliter sample was directly injected without any pretreatment in a CHCl3 stream at 2 mL min−1 into a closed system and the FTIR spectra of sample and standard solutions were obtained using a nominal resolution of 4 cm−1 from 4000 to 900 cm−1 spectral region and accumulating 2 scans per spectrum. Propamocarb determination was based on the measurement of flow injection analysis (FIA) recording height established from FTIR peak area measurements from 1713 to 1703 cm−1 corrected using a baseline defined at 2000 cm−1. The concentration of Propamocarb in samples was calculated by interpolation in an external calibration line obtained from several injections of 2 μL of a 47% (w/v) standard solution into the CHCl3 closed system. This procedure provided a limit of detection of 0.8% (w/v) in the original sample, a sensitivity of 0.3190 absorbance units mL mg−1 for a pathlength of 0.11 mm and a relative standard deviation of 0.2% for five independent measurements at 0.74 mg mL−1 concentration level. The maximum sampling frequency of the whole procedure was 34 h−1 and the waste generation was reduced to only 2 mL of CHCl3 solution per sample and additional 2 mL for the whole calibration line.