Kaval Necati, Seliskar Carl J, Heineman William R
Department of Chemistry, University of Cincinnati, PO Box 210172, Cincinnati, Ohio 45221-0172, USA.
Anal Chem. 2003 Nov 15;75(22):6334-40. doi: 10.1021/ac0347664.
A fluorescence spectroelectrochemical sensor capable of detecting very low concentrations of metal complexes is described. The sensor is based on a novel spectroelectrochemical sensor that incorporates multiple internal reflection spectroscopy at an optically transparent electrode (OTE) coated with a selective film to enhance detection limits by preconcentrating the analyte at the OTE surface. Nafion was used as the selective cation exchange film for detecting Ru(bpy)(3)(2+), the model analyte, which fluoresces at 605 nm when excited with a 441.6-nm HeCd laser. The unoptimized linear dynamic range of the sensor for Ru(bpy)(3)(2+) is between 1 x 10(-)(11) and 1 x 10(-)(7) M with a calculated 2 x 10(-)(13) M detection limit. The sensor employs extremely thin films ( approximately 12 nm) without significantly sacrificing its sensitivity. The sensor response is demonstrated with varying film thicknesses. A state-of-the-art flow cell design allows variable cell volumes as low as approximately 4 microL. Fluorescence of the sample can be controlled by electromodulation between 0.7 and 1.3 V. Sensor operation is not reversible for the chosen model film (Nafion) and sample (Ru(bpy)(3)(2+)) but it can be regenerated with ethanol for multiple uses.
本文描述了一种能够检测极低浓度金属络合物的荧光光谱电化学传感器。该传感器基于一种新型光谱电化学传感器，它在涂有选择性薄膜的光学透明电极（OTE）上采用了多重内反射光谱技术，通过在OTE表面预富集分析物来提高检测限。使用Nafion作为选择性阳离子交换膜来检测模型分析物Ru(bpy)(3)(2+)，当用441.6 nm的氦镉激光激发时，该分析物在605 nm处发出荧光。该传感器对Ru(bpy)(3)(2+)未经优化的线性动态范围在1×10(-11)至1×10(-7) M之间，计算得出的检测限为2×10(-13) M。该传感器采用极薄的薄膜（约12 nm），而不会显著牺牲其灵敏度。通过改变薄膜厚度展示了传感器的响应。一种先进的流通池设计允许可变的池体积低至约4 μL。样品的荧光可以通过在0.7至1.3 V之间进行电调制来控制。对于所选的模型薄膜（Nafion）和样品（Ru(bpy)(3)(2+)），传感器操作是不可逆的，但可以用乙醇再生以进行多次使用。
