School of Materials Science and Technology, Indian Institute of Technology, Banaras Hindu University, Varanasi, 221005, India.
Mikrochim Acta. 2018 Mar 16;185(4):224. doi: 10.1007/s00604-018-2753-2.
The authors have synthesized molybdenum disulfide nanosheets (MoS nanosheets) by using a bottom-up hydrothermal method. The nanosheets display strong catalytic (enzyme mimetic) activity in catalyzing the oxidation of peroxidase substrate of 3,3',5,5'-tetramethylbenzidine (TMB) in presence of HO to produce a blue product. The peroxidase mimicking properties of MoS nanosheets depend on temperature, HO concentration and pH value. A choline assay was worked out where choline was oxidized by choline oxidase in presence of oxygen to produce HO which is colorimetrically detected, best at 652 nm. The method works in the 1 to 180 μM choline concentration range with a 0.4 μM detection limit. Color changes may also be detected visually. The assay is simple, highly sensitive, selective and rapid. It was applied in the determination of choline in (spiked) milk and serum. Graphical abstract Basic principle of intrinsic peroxidase-like activity of MoS nanosheets, applied to design a rapid and selective colorimetric assay for choline detection based on the tetramethylbenzidine (TMB) color reaction.
作者通过使用自下而上的水热法合成了二硫化钼纳米片（MoS 纳米片）。这些纳米片在 HO 的存在下，可作为过氧化物酶的模拟物，催化 3,3',5,5'-四甲基联苯胺（TMB）过氧化物酶底物的氧化，生成蓝色产物。MoS 纳米片的过氧化物酶模拟特性取决于温度、HO 浓度和 pH 值。作者建立了一种胆碱检测方法，在该方法中，胆碱在氧存在下被胆碱氧化酶氧化生成 HO，HO 可通过比色法检测，在 652nm 处检测效果最佳。该方法在 1 至 180μM 胆碱浓度范围内有效，检测限为 0.4μM。颜色变化也可以通过肉眼观察到。该测定方法简单、灵敏、选择性高、快速。它被应用于（添加）牛奶和血清中胆碱的测定。
