Sensitive determination of organophosphorus pesticide residues in fruits and vegetables by solid phase extraction and enzyme inhibition UV-spectrophotometry

This study presents the development and validation of UV-spectrophotometry methods for the quantification of organophosphorus pesticide residues in fruits and vegetables based on solid phase extraction and the principle of enzyme inhibition of catalase. A silica gel modified with 3,3 ‘- dodecyl-1,1’ - di-1-vinylimidazolium bromide ionic liquid (Poly - (3,3 ‘- dodecane-1,1’ - bis-1-vinylimidazolium dibromide modified silica), Poly (DBVD) - Sil, is used as a solid-phase extraction adsorbent. At the same time, based on the principle of enzyme inhibition of catalase, bovine liver catalase was screened as the enzyme solution, and a rapid detection method for profenofos residue was established by solid-phase extraction UV-spectrophotometry by optimizing the reaction conditions. That CAT inhibited the oxidation of MB by H2O2, limited MB fading, and the degree of absorbance recovery was related to CAT activity. Profenofos has a significant inhibitory effect on catalase, with a decrease in absorbance values. The natural logarithm of profenofos is linearly related to the enzyme activity inhibition rate within the range of 0.001-5.0 mg/L, the linear regression equation is y = 0.0509x + 0.4341, with R2=0.9968, the detection limit (3s/k) is 3.1 × 10−4 mg/L. A standard recovery rate of 95.3% to 104.2% for profenofos. The results showed the method is simple, fast, precise, accurate, and has a low detection limit, meeting the needs of rapid detection of profenofos residues in fruits and vegetables.