State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau, 999078, China.
Institute of Applied Physics and Materials Engineering, University of Macau, Macau, 999078, China.
Mikrochim Acta. 2019 Jan 9;186(2):66. doi: 10.1007/s00604-018-3175-x.
Nanoceria with a remarkable phosphatase mimicking activity was synthesized and used to catalyze the hydrolysis of phosphate esters in pH 10 solution. The catalytic effect of nanoceria was firstly investigated by selecting p-nitrophenyl phosphate as a model substrate. The pH value, incubation temperature, reaction time, and concentration of nanoceria were optimized. The catalytic effect was then confirmed by using methyl-paraoxon as a substrate. The p-nitrophenol anion released by the enzyme mimic is yellow and exerts an inner filter effect on the fluorescence of the carbon dots (with excitation/emission maxima at 400/520 nm). Response to methyl-paraoxon is linear in the 1.125-26.25 μmol L concentration range. The method was applied to the determination of pesticides in spiked Panax quinquefolius and water samples. Recoveries ranged from 85 to 103% (n = 3). The technique is rapid, reliable, and can be used for on-site detection of pesticides and organophosphates. Graphical abstract Schematic presentation of a fluorometric technique for the detection of organophosphate compound and pesticide using nanoceria as a phosphatase mimic and an inner filter effect on the blue fluorescence of carbon dots (with excitation/emission maxima at 400/520 nm).
合成了具有显著磷酸酶模拟活性的纳米氧化铈，并将其用于在 pH 10 溶液中催化磷酸酯的水解。首先通过选择对硝基苯磷酸作为模型底物来研究纳米氧化铈的催化作用。优化了 pH 值、孵育温度、反应时间和纳米氧化铈的浓度。然后使用甲基对氧磷作为底物来确认催化效果。酶模拟物释放的对硝基苯酚阴离子是黄色的，并对碳点（激发/发射最大值为 400/520nm）的荧光产生内滤效应。对甲基对氧磷的响应在 1.125-26.25μmol L 浓度范围内呈线性。该方法用于测定党参和水样中添加的农药。回收率在 85%至 103%之间（n=3）。该技术快速、可靠，可用于现场检测有机磷化合物和农药。
