Monitoring of the insecticide trichlorfon by phosphorus-31 nuclear magnetic resonance (31P NMR) spectroscopy

Trichlorfon is an organophosphorus insecticide, which is extensively being used for protection of fruit crops. Trichlorfon is a thermal labile compound, which cannot be easily determined by gas chromatography (GC) and has no suitable group for sensitive detection by high performance liquid chromatography (HPLC). In this study, a 31P nuclear magnetic resonance (31P NMR) has been described for monitoring of trichlorfon without any separation step. The quantitative works of 31P NMR spectroscopy has been performed in the presence of an internal standard (hexamethylphosphoramide). Limit of detection (LOD) for this method has been found to be 55 mg L−1, without any sample preparation, and the linear working range was 150–5500 mg L−1. Relative standard deviation (R.S.D.%) of the method for three replicates within and between days was obtained ≤9%. The average recovery efficiency was approximately 99–112%. This method was applied for monitoring trichlorfon in a commercial insecticide sample and tomato sample.