Inspired by the photoelectrochemical (PEC) properties of TiO₂ nanotubes arrays (TNA) and their application as a super vessel for immobilizing biomolecules, we constructed an inhibition-effect PEC biosensor for determination of asulam based on the in-situ generation of CdS quantum dots (QDs) on TNA using an enzymatic reaction. Horseradish peroxidase (HRP) enzyme was covalently assembled on the inner-wall of TNAs, which exhibited good electrochemical and catalytic properties. In the mixture solution containing H₂O₂, CdY and S₂O₃^2-, HRP enzyme in TNAs catalyzed H₂O₂ reduce S₂O₃^2- to S^2-. The generated S^2- reacted with CdY to form CdS QDs in situ on the TNAs, improving the PEC performance of TNA under visible light irradiation. The photocurrent would decrease after addition of asulam due to its inhibitory effect towards HRP enzyme activity. Under the optimal experimental conditions, the constructed PEC TNA/HRP biosensor exhibited a satisfying linear range (0.02–2.0 ng mL⁻¹), low limit of detection (4.1 pg mL⁻¹) and good selectivity towards asulam determination, and has been successfully applied for the analysis of real environmental water samples with good accuracy of the recoveries ranged from 90% to 114%.

受到TiO ₂纳米管阵列（TNA）的光电化学（PEC）特性及其作为固定化生物分子的超级容器的应用的启发，我们构建了一种抑制效应PEC生物传感器，用于基于CdS量子点的原位生成测定芥子气素。 （QDs）在TNA上使用酶促反应。辣根过氧化物酶（HRP）被共价组装在TNAs的内壁上，具有良好的电化学和催化性能。在含有H ₂ O ₂，CdY和S ₂ O ₃ ^2-的混合溶液中，TNA中的HRP酶催化H ₂ O ₂还原S ₂ O ₃ ^2-到S ^2-。生成的S ^2-与CdY反应，在TNA上原位形成CdS QD，提高了可见光照射下TNA的PEC性能。加入阿苏拉姆后，由于其对HRP酶活性的抑制作用，光电流会降低。在最佳实验条件下，构建的PEC TNA / HRP生物传感器表现出令人满意的线性范围（0.02–2.0 ng mL ^-1），低检测限（4.1 pg mL ^-1）和对确定无定形的良好选择性，并且已经成功完成用于实际环境水样的分析，回收率好，准确度从90％到114％。