Abstract: ³¹P NMR was used to analyze the contents of malathion and primary organic phosphorus impurities in malathion EC. All ³¹P NMR spectra were recorded on a Bruker Avance 600 spectrometer at 25 ℃ with 85% H₃PO₄ used as an internal standard. The contents of malathion, isomalathion, MeOOSPS trimester, MeOOOPS trimester and malaoxon in malathion EC were found to be 44.92%, 0.55%, 0.05%, 0.22% and 0.11% respectively, and the RSD 0.07%, 2.10%, 2.88%, 0.94% and 1.58% respectively. The results indicated that ³¹P NMR method is an effective tool for analyzing malathion EC, and thus useful in practical pesticide analyses.

Key words: ³¹P NMR, analysis, malathion, impurities