Department of Chemistry, Capital Normal University, Beijing, 100048, China.
Zhengzhou Prevention and Treatment Center for Occupational Diseases, Zhengzhou, 450003, China.
Mikrochim Acta. 2018 Jan 25;185(2):131. doi: 10.1007/s00604-018-2675-z.
The authors report that cobalt oxyhydroxide (CoOOH) nanoflakes possess intrinsic oxidizing ability to directly oxidize 3,3',5,5'-tetramethylbenzidine (TMB) to form a blue colored product (oxTMB) even in the absence of HO and oxygen. In the presence of ascorbic acid (AA), less of the blue product is formed because AA reduces oxTMB. These findings constitute a new scheme for colorimetric detection of AA. Absorbance, best measured at 652 nm, linearly drops in the 10 nM to 1 μM AA concentration range, and the limit of detection is 5 nM (at an S/N ratio of 3). The reaction is complete within <5 s and highly selective. A strip test has been designed for fast and on-spot visual detection of AA. The method was applied to the direct estimation of AA in the microdialysate of brain, and also in soft drink samples. The strip test is considered to be a promising tool for the rapid screening of AA in brain and commercial samples. Graphic abstract Schematic of the CoOOH-TMB colorimetric system that exhibits a high selectivity for ascorbic acid (AA). A strip test has been designed for fast and on-spot visual detection of AA.
作者报告称，钴氢氧化物 (CoOOH) 纳米薄片具有内在的氧化能力，即使在没有 HO 和氧气的情况下，也能将 3,3',5,5'-四甲基联苯胺 (TMB) 直接氧化成蓝色产物 (oxTMB)。在抗坏血酸 (AA) 的存在下，由于 AA 会还原 oxTMB，因此形成的蓝色产物较少。这些发现构成了比色法检测 AA 的新方案。在 652nm 处测量的吸光度在 10nM 至 1μM AA 浓度范围内呈线性下降，检测限为 5nM（信噪比为 3）。反应在 <5s 内完成，且具有高度选择性。已经设计了一种条带测试来快速、现场可视化检测 AA。该方法已应用于脑微透析液中 AA 的直接估计，以及软饮料样品中 AA 的直接估计。该条带测试被认为是快速筛选脑和商业样品中 AA 的有前途的工具。
