Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221-0172, USA.
Anal Chem. 2010 Dec 1;82(23):9743-8. doi: 10.1021/ac101883a. Epub 2010 Nov 5.
A spectroelectrochemical sensor was demonstrated for an organic compound whose oxidation proceeds through an electron transfer-chemical reaction-electron transfer (ECE) mechanism to generate new chemical species that are used for detection by fluorescence. The polycyclic aromatic hydrocarbon 1-hydroxypyrene (1-PyOH) served as a representative model analyte. The spectroelectrochemical properties of 1-PyOH in solution were explored with an optically transparent thin layer electrode. Electrochemical oxidation of 1-PyOH under acidic conditions proceeds via the ECE mechanism to a diquinonepyrene, which shows reversible electrochemistry and fluoresces at 425 nm in its reduced form, dihydroxypyrene. The sensor consisted of a tin-doped indium optically transparent electrode coated with a Nafion thin-film (20 nm) that rapidly preconcentrated the analyte at the sensor surface. Fluorescence in the film was excited by the evanescent wave from attenuated total reflection spectroscopy. Electrochemical modulation of dihydroxypyrene fluorescence at 425 nm in the 500 to -200 mV (vs Ag/AgCl) potential range was used for indirect detection of 1-PyOH. The spectroelectrochemical sensor calibration curve had a range of 5 × 10(-9) to 1 × 10(-6) M with a calculated detection limit of 1 × 10(-9) M.
一种用于有机化合物的光谱电化学传感器得以展示，该化合物的氧化过程通过电子转移-化学反应-电子转移（ECE）机制进行，从而生成新的化学物质，用于荧光检测。多环芳烃 1-羟基芘（1-PyOH）被用作代表性的模型分析物。采用光学透明薄层电极探索了 1-PyOH 在溶液中的光谱电化学性质。在酸性条件下，1-PyOH 的电化学氧化通过 ECE 机制进行，生成二醌芘，其在还原形式二羟芘中显示可逆电化学和在 425nm 处荧光。传感器由涂有 Nafion 薄膜（20nm）的掺锡铟光学透明电极组成，该薄膜可快速将分析物预浓缩在传感器表面。薄膜中的荧光通过衰减全反射光谱的消逝波激发。在 500 至-200 mV（相对于 Ag/AgCl）的电位范围内，电化学调制 425nm 处二羟芘的荧光用于间接检测 1-PyOH。光谱电化学传感器的校准曲线范围为 5×10(-9)至 1×10(-6)M，计算出的检测限为 1×10(-9)M。
