Herein, we introduce a novel method for tryptophan detection via a reduction reaction facilitated by its interaction with a copper(II) phthalocyanine (CuPc) electrocatalytic electrode. This method addresses challenges associated with the susceptibility of the oxidation response to interference from various species when measuring tryptophan in bodily fluids. The reduction currents exhibit a linear increase with tryptophan concentrations in two ranges: 0.0013–0.10 mM and 0.10–1.20 mM, with the sensitivities of 14.7 ± 0.5 μA mM⁻¹ and 3.5 ± 0.1 μA mM⁻¹, respectively. The limit of detection (LOD, 3S_B/m) is determined to be 0.39 μM. The sensor exhibits excellent reproducibility, with the relative standard deviation of <5%. Application of the sensor to authentic urine samples yields a % recovery of 101 ± 4%.

中文翻译：

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铜(II)酞菁作为电催化电极用于尿色氨酸的阴极检测

在此，我们介绍了一种通过还原反应来检测色氨酸的新方法，该还原反应是通过其与铜（II）酞菁（CuPc）电催化电极的相互作用来促进的。该方法解决了测量体液中色氨酸时氧化反应对各种物种干扰的敏感性相关的挑战。还原电流在两个范围内随色氨酸浓度呈线性增加：0.0013–0.10 mM 和 0.10–1.20 mM，灵敏度分别为 14.7 ± 0.5 μA mM ⁻¹和 3.5 ± 0.1 μA mM ⁻¹。检测限 (LOD, 3 SB _/ m )确定为 0.39 μM。该传感器表现出优异的再现性，相对标准偏差<5%。将传感器应用到真实的尿液样本中，回收率达到 101 ± 4%。