Organophosphorus pesticides determination by novel HPLC and spectrophotometric method

- Methods are efficient for the determination of chlorpyrifos and prophenofos pesticides in vegetables.
- Methods are accurate, precise, sensitive, robust and easy to apply.
- Result indicates SPE is time effective and efficient as compared to the LLE.
- The developed HPLC method is LC-MS compatible & highly sensitive as the lowest.
- Quantification limit is 0.0016 μg/ml for chlorpyrifos and 0.0028 μg/ml for prophenofos.

The present work describes a novel HPLC and UV-spectrophotometric method for the simultaneous estimation of chlorpyrifos and prophenofos in vegetables and fruits. In UV method, the absorbance of chlorpyrifos and prophenofos was measured at wavelength 277 nm and 289 nm respectively and quantitation was carried out by first order derivative method. The calibration curve for chlorpyriphos and prophenofos was found to be linear in the range of 6-16 μg/mL with correlation coefficient 0.9979 and 0.9993 respectively. The HPLC separation was achieved on Hibar C18 column (250 × 4.6 mm, 5 µ) using mobile phase consist of acetonitrile: water (90:10, v/v) at flow rate 1.0 mL/min and the eluent was monitored at 219 nm. Pesticides were extracted from the samples by solid phase extraction and liquid-liquid extraction before the analysis. Out of these two extraction methods, solid phase extraction was found more efficient in terms of % recovery as compared to liquid-liquid extraction. The developed method was applied for estimation of chlorpyrifos and prophenofos and it was found that the chlorpyrifos was 0.018 mg/kg, which is above maximum residue limits (0.01 mg/kg), which might be toxic to body. Prophenofos was not found in any collected samples of vegetables and fruits.