Herein, a di-branched di-anchoring dye, T(TA)2, with triphenylamine as electron donor, thiophene as electron transfer π-bridge, and acrylic acid as both acceptor and anchoring groups, was synthesized and coupled with TiO2 nanoparticles for the highly sensitive photoelectrochemical (PEC) assay of organophosphate pesticides (OPs). The T(TA)2 exhibited good anchoring stability to TiO2 nanoparticles in neutral buffer solutions. Under 2 h continual irradiation, the T(TA)2-TiO2 nanocomposites respectively kept 99.7% and 85.9% of their initial photocurrents in neutral Tris-HCl and phosphate buffer solutions. Neither degradation nor desorption of T(TA)2 from TiO2 nanoparticles was observed during the continual irradiation in the Tris-HCl solutions. The stability was not only superior to its analogues either possessing one branch, with cyanoacrylic acid as anchoring groups, or without thiophene in the π-bridge, but also better than the Ru(II) complex N719 and the porphyrin dye sensitized TiO2 nanocomposites. The nanocomposites also showed highly photocatalytic ability towards the oxidation of ascorbic acid and thiocholine (TCh). Since the latter is the enzymatic hydrolysis product of acetylcholinesterase (AChE) and the activity of AChE can be inhibited by OPs, the T(TA)2-TiO2/FTO was further used for PEC assay of OPs. Using parathion as a model analyte, the PEC method showed a wide linear range from 2 × 10-12-4 × 10-6 g mL-1 and an extremely low limit of detection of 5.6 × 10-13 g mL-1. Regarding these good analytical performances, this study may provide some guidance and pave the way for the applications of dye-TiO2 nanocomposites in a lot of PEC devices required to be performed in aqueous solutions.

中文翻译：

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具有良好光稳定性的二支化三苯胺染料敏化TiO 2 纳米复合材料用于有机磷农药的灵敏光电化学检测

在此，合成了以三苯胺为电子供体、噻吩作为电子转移 π 桥、丙烯酸作为受体和锚定基团的双支化双锚定染料 T(TA)2，并与 TiO2 纳米颗粒偶联，用于有机磷农药 (OP) 的高灵敏度光电化学 (PEC) 测定。T(TA)2 在中性缓冲溶液中对 TiO2 纳米颗粒表现出良好的锚定稳定性。在 2 小时的连续照射下，T(TA)2-TiO2 纳米复合材料在中性 Tris-HCl 和磷酸盐缓冲溶液中分别保持其初始光电流的 99.7% 和 85.9%。在 Tris-HCl 溶液中连续照射期间，未观察到 T(TA)2 从 TiO2 纳米颗粒降解或解吸。稳定性不仅优于它的同类产品或拥有一个分支，以氰基丙烯酸作为锚定基团，或在 π 桥中没有噻吩，但也优于 Ru(II) 络合物 N719 和卟啉染料敏化的 TiO2 纳米复合材料。纳米复合材料还显示出对抗坏血酸和硫代胆碱 (TCh) 氧化的高度光催化能力。由于后者是乙酰胆碱酯酶 (AChE) 的酶解产物，且 AChE 的活性可被 OPs 抑制，因此 T(TA)2-TiO2/FTO 进一步用于 OPs 的 PEC 测定。使用对硫磷作为模型分析物，PEC 方法显示出 2 × 10-12-4 × 10-6 g mL-1 的宽线性范围和 5.6 × 10-13 g mL-1 的极低检测限。对于这些良好的分析性能，