The abuse of tetracycline (TC) has led to serious threats to human health and the environment. Therefore, the rapid and sensitive detection of tetracycline is of particular importance. Herein, we successfully synthesised a bimetallic nanozyme D-Fe/Co-MOF with oxidase activity and established a colourimetric sensor. The complex of Fe2+ in D-Fe/Co-MOF and TC can release hydroxyl radicals (˙OH) and promote the oxidation of TMB. As a result, the colour of the detection system significantly changes, enabling the sensitive colourimetric detection of TC. Compared with the existing Fe/Co-MOF sensor, D-Fe/Co-MOF can effectively reduce the detection error caused by hydrogen peroxide decomposition, improving the accuracy of TC detection. Under the optimal conditions, the absorbance at 652 nm showed a good linear relationship with TC concentration in the range of 0.35–220 μg mL−1. The detection limit was as low as 0.0719 μg mL−1, considerably lower than the national safety standard. The proposed colourimetric sensor was also successfully used for the detection of TC in actual milk samples, and the results were in good agreement with those obtained via liquid chromatography. The proposed strategy for the detection of TC in food is expected to contribute to ensuring food safety and human health.
Ying Fang,Qianwen Liu,Yang Song,Feiyue Jia,Ying Yang,Haipu Li
Dissolved organic matter (DOM) extensively exists in high-arsenic groundwater with relatively high concentration, which could not only compete with arsenic for adsorption sites, but also depress As(III) oxidation in persulfate-based advanced processes (PS-AOPs) through scavenging free radicals (SO 4 • − and •OH). In order to effectively avoid the negative effect of DOM , an Fe/Co bimetallic metal–organic framework (Fe/Co MOF)-coupled peroxymonosulfate (Fe/Co MOF-PMS) system was rationally constructed for non-radical-dominated As(III) oxidation and chemisorption-driven As(V) adsorption. Results showed that the Fe/Co MOF-PMS system did realize anti-interference As(III) immobilization in DOM-rich high-arsenic groundwater, which was evidenced by no difference in As(III) immobilization efficiencies in the absence and presence of 20 mg/L humic acid (HA). During the oxidation process, 1 O 2 dominated As(III) oxidation while O 2 • − dominated HA oxidation, and the presence of HA significantly promoted the generation of 1 O 2 besides SO 4 • − and •OH. During the adsorption process, chemical adsorption mainly drove As(V) adsorption such as forming M-O-As (M = Fe, Co) bond, while physical adsorption forces played a major role in HA adsorption, such as π-π interaction, hydrogen bonding, and electrostatic attraction. The synergism of oxidation and adsorption processes made the anti-interference As(III) immobilization in DOM-rich high-arsenic groundwater in Fe/Co MOF-PMS system come true. This work is believed to shed light on the highly efficient purification of DOM-rich high-arsenic groundwater.
危险品化学品经营许可证（带存储）