College of Chemistry and Bioengineering, Guilin University of Technology, Guilin, 541004, Guangxi, China.
Guangxi Key Laboratory of Electrochemical and Magnetochemical Function Materials, Guilin, 541004, Guangxi, China.
Mikrochim Acta. 2023 Jul 1;190(7):280. doi: 10.1007/s00604-023-05863-3.
A novel extended-gate field-effect transistor (FET) photoelectrochemical (EGFET PEC) sensor was designed for highly sensitive detection of L-cysteine (L-Cys). TiO was initially modified on the ITO electrode by the sol-gel dip-coating method and calcined to produce TiO/ITO. Then, CdS was synthesized on the TiO surface by hydrothermal method to obtain the CdS-TiO heterojunction material. CdS/TiO/ITO was connected to the gate of the FET to obtain an EGFET PEC sensor. Under the irradiation of a xenon lamp simulating visible light, the CdS/TiO heterojunction composite absorbs light energy to produce photogenerated electron-hole pairs, which have strong photocatalytic oxidation activity and oxidize L-Cys covalently identified by Cd(II) through CdS covalent. These pairs generate a photovoltage that controls the current between the source and the drain to detect L-Cys. Under the optimized experimental conditions, the optical drain current (I) of the sensor exhibited a good linear relationship with the logarithm of L-Cys in the range of 5.0 × 10-1.0 × 10 mol/L, and the detection limit was 1.3 × 10 mol/L (S/N = 3), which is lower than the values reported by other detection methods. Results showed that the CdS/TiO/ITO EGFET PEC sensor revealed high sensitivity and good selectivity. The sensor has been used to determine L-Cys in urine samples.
一种新型的扩展栅场效应晶体管（EGFET）光电化学（PEC）传感器被设计用于高灵敏度检测 L-半胱氨酸（L-Cys）。首先通过溶胶-凝胶浸渍法在 ITO 电极上修饰 TiO，并进行煅烧以产生 TiO/ITO。然后，通过水热法在 TiO 表面合成 CdS，以获得 CdS-TiO 异质结材料。将 CdS/TiO/ITO 连接到 FET 的栅极上，以获得 EGFET PEC 传感器。在模拟可见光的氙灯照射下，CdS/TiO 异质结复合材料吸收光能产生光生电子-空穴对，具有很强的光催化氧化活性，并通过 CdS 共价键氧化与 Cd(II)共价键合的 L-Cys。这些对生成控制源极和漏极之间电流的光电压，以检测 L-Cys。在优化的实验条件下，传感器的光漏电流（I）与 L-Cys 的对数在 5.0×10-1.0×10 mol/L 范围内呈现良好的线性关系，检测限为 1.3×10 mol/L（S/N=3），低于其他检测方法的报道值。结果表明，CdS/TiO/ITO EGFET PEC 传感器具有高灵敏度和良好的选择性。该传感器已用于测定尿样中的 L-Cys。
