Detection of nitrite in tobacco leaf using Ce-PCN-222-based peroxidase colori-metric probe
In this study,cerium-doped porphyrin-organic framework compound(Ce-PCN-222)nanozyme with uniform cubic morphology was synthesized.Based on the enhancement effect of nitrite(NO2-)on the peroxidase activity of Ce-PCN-222,a simple and sensitive colometry probe method was established for the determination of NO2-in tobacco leaves.Ce-PCN-222 with peroxidase-like activity could catalyze the oxidation of colorless 2,2-diazo-bis(3-ethyl-benzothiazole-6-sulfonic acid)diamiammonium salt(ABTS)to green ox-ABTS in the presence of H2O2,with an obvious absorption peak at 415 nm.Ce-PCN-222 showed a strong adsorption effect on NO2-,while ABTS and ox-ABTS have weak oxidation reduction(REDOX)and diazotization reactions with NO2-.The results of catalysis kinetics showed that NO2-could effectively improve the substrate affinity of Ce-PCN-222.Thus,the enzymatic catalytic effect of Ce-PCN-222 was improved in a short time.In the concentration range of 0.05-20 mg/L,the absorbance at 415 nm(A415)showed a good linear relationship with the concentration of NO2-,and the detection limit was 0.01 mg/L.The method was applied to the determination of NO2-in tobacco leaves,and the recoveries were in the range of 84.5%-105.3%.
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