Rapid screening of tetracycline residues in food based on Fe3O4/poly(styrene-4- vinyl pyridine) nanocomposites

A rapid screening method for tetracycline residues in milk and honey samples was developed based on the inhibitory effect of tetracycline on the peroxidase activity of Fe3O4/poly(styrene-4-vinylpyridine)(Fe3O4/P(st- 4vp)). Under acidic conditions, the prepared Fe3O4/P(st-4vp) was able to catalyze the oxidation of 3,3,5,5'- tetramethylbenzidine (TMB) by H2O2 to produce blue oxidized TMB (oxTMB), with a characteristic absorption peak at 652 nm. The reaction was inhibited by tetracycline, which showed the strongest inhibition of Fe3O4/P(st- 4vp) enzyme activity under conditions of pH 5.0, 50 °C of water bath, 20 min of reaction time, 10 mmol/L of H2O2, 1.0 mg/mL of Fe3O4/P(st-4vp), and 0.36 mmol/L of TMB. Based on the relationship curve between tetracycline concentration and enzyme inhibition rate, the spiked tetracycline in milk and honey samples was screened, and the results showed that the screening range of Fe3O4/P(st-4vp) for tetracycline spiked in milk and honey was 5-197.5 µg/kg, and the relative accuracy were 94.4% and 96.3%, respectively. © 2024, Youke Publishing Co.,Ltd. All rights reserved.