Construction of cerium-containing organophyllosilicate nanozyme for colorimetric determination of nitrite in food

In this study, cerium containing organophyllosilicate (CeAC) was constructed via one-step sol-gel method. The synthesized CeAC exhibited exceptional peroxide-like catalytic activity, facilitating the oxidation of colorless 3,3',5,5 '-tetramethylbenzidine (TMB) to the blue colored TMBox in the presence of hydrogen peroxide (H2O2). Subsequently, CeAC-TMB-H2O2 colorimetric system was employed for the determination of nitrite (NO2−) in food. A good linear relationship between A652/A445 and the logarithm of NO2−concentration in the range of 10~200 μM was achieved, as well as an extremely low limit of detection at 0.365 μM. Moreover, the accuracy and precision determined in spiked samples through quantitative visualization is in the range of 92.4% to 118.4% with a coefficient of variation below 8.25%, representing a significant advantage over other reported systems. Finally, the CeAC catalytic system was applied to determine the nitrite in real food, it showed a similar but more accurate result compared to the commercial kit. Overall, this study presents a high-specificity, accurate and precise on-line visual method for the determination of nitrite in food.