L‐cysteine plays a vital role in organisms, and is an important biomarker for many pathological diseases that seriously affect human health. In the study, a photoelectrochemical (PEC) probe with zinc‐tetramine phthalocyanine covalently grafted to graphene oxide (ZnTAPc‐Gr) was developed for L‐cysteine detection. Graphene oxide (GO) with carboxyl was used to immobilize zinc‐tetramine phthalocyanine (ZnTAPc) with amidogen (a graft structure formed by an amide covalent bond), which could firmly immobilize ZnTAPc, thereby improving the photoelectrochemical performance and stability. L‐cysteine molecule, an electron acceptor, was specifically recognized by the PEC probe, exhibiting a decrease in the photocurrent signal. Under the optimal experimental conditions, the fabricated PEC probe exhibited excellent performance in L‐cysteine analysis within a linear range of 0.25–113 μM and a detection limit of 11.4 nM. The PEC probe showed high sensitivity, selectivity, and stability. The method described herein provides an effective strategy for PEC probe construction for L‐cysteine detection, and can also serve as a promising PEC platform for the analyses of other small molecules.

中文翻译：

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使用共价接枝的ZnTAPc-Gr基探针对L-半胱氨酸进行光电化学检测

L-半胱氨酸在有机体中起着至关重要的作用，并且是许多严重影响人类健康的病理性疾病的重要生物标志物。在这项研究中，开发了一种光电化学（PEC）探针，该探针具有共价接枝到氧化石墨烯（ZnTAPc-Gr）上的四胺锌酞菁锌，用于L-半胱氨酸检测。带有羧基的氧化石墨烯（GO）用于固定具有酰胺基（酰胺共价键形成的接枝结构）的锌四胺酞菁锌（ZnTAPc），可以牢固地固定ZnTAPc，从而提高光电化学性能和稳定性。L-半胱氨酸分子是一种电子受体，被PEC探针特异性识别，显示出光电流信号的减少。在最佳实验条件下，制成的PEC探针在0.25–113μM的线性范围内和11.4 nM的检出限内，在L-半胱氨酸分析中表现出出色的性能。PEC探针显示出高灵敏度，选择性和稳定性。本文描述的方法为构建L-半胱氨酸的PEC探针提供了有效的策略，并且还可以用作分析其他小分子的有前途的PEC平台。