乙醇胺介导Mn2+生成锰氧化合物的快速制备及其在亚硝酸盐检测中的应用OA

A manganese oxide nanozyme(MEA-MnOx)was synthesized using ethanolamine(MEA)and divalent manganese ions(Mn2+).Its morphology and structure were characterized by transmission electron microscopy(TEM),Fourier transform infrared spectroscopy(FT-IR),X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS).Results showed that MEA-MnOx oxidize colorless 3,3',5,5'-tetramethylbenzidine(TMB)to a blue oxidized TMB complex with a maximum absorbance at 652 nm.The Michaelis constant(Km)for the catalytic oxidation of TMB was determined to be 0.01729 mmol/L.Under acidic conditions,nitrite reacts with the blue TMB complex to produce a yellow diazo derivative(λmax=445 nm).Based on on the inverse relationship betwen the ratio of absorbance intensities at 652 nm and 445 nm(A652/A445)and the natural logarithm of nitrite concentration,a ratiometric colorimetric sensing method was developed for nitrite detection.This method exhibited a linear range of 2～200 μmol/L and a detection limit(LOD)of 0.56 μmol/L.Additionally,a smartphone-based detection approach was established by photographing solutions containing different concentrations of nitrite and extracting RGB values via the WeChat mini-program"Color Recognition."A relationship between the B/G value and nitrite concentration was used,yielding a linear detection range of 5～130 μmol/L.The corresponding LOD was 1.93 μmol/L.The sensor was successfully applied to detect nitrite in real samples,including ham sausage and water samples,with satisfactory recoveries(102.7％～109.5％for water and 103.2％～115.1％for ham sausage).This work provides a new analytical approach for nitrite detection in the fields of food safety and environmental monitoring.