This work describes an electrochemical sensor for the fast noninvasive detection of uric acid (UA) in saliva. The sensing material was based on a cobalt-containing Prussian blue analogue (Na_2−xCo[Fe(CN)₆]_1−y, PCF). By optimizing the ratio of Co and Fe as 1.5 : 1 in PCF (PCF_1.5,0), particles with a regular nanocubic morphology were formed. The calcination of PCF_1.5,0 produced a carbon-coated CoFe alloy (CCF_1.5), which possessed abundant defects and achieved an excellent electrochemical performance. Subsequently, CCF_1.5 was modified on a screen-printed carbon electrode (SPCE) to fabricate the electrochemical sensor, CCF_1.5/SPCE, which showed a sensitive and selective response toward salivary UA owing to its good conductivity, sufficient surface active sites and efficient catalytic activity. The determination of UA in artificial saliva achieved the wide linear range of 40 nM–30 μM and the low limit of detection (LOD) of 15.3 nM (3σ/s of 3). The performances of the sensor including its reproducibility, stability and selectivity were estimated to be satisfactory. The content of UA in human saliva was determined and the recovery was in the range of 98–107% and the total RSD was 4.14%. The results confirmed the reliability of CCF_1.5/SPCE for application in noninvasive detection.

中文翻译：

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用于无创尿酸传感的纳米立方含钴普鲁士蓝类似物衍生的碳包覆 CoFe 合金纳米颗粒

这项工作描述了一种用于快速无创检测唾液中尿酸（UA）的电化学传感器。传感材料基于含钴的普鲁士蓝类似物（Na _{2− x} Co[Fe(CN) ₆ ] _{1− y}，PCF）。通过优化 PCF 中 Co 和 Fe 的比例为 1.5:1 (PCF _1.5,0 )，形成了具有规则纳米立方形貌的颗粒。 PCF _1.5,0的煅烧产生了碳包覆的CoFe合金（CCF _1.5），该合金具有丰富的缺陷并具有优异的电化学性能。随后，在丝网印刷碳电极（SPCE）上对CCF _{1.5进行修饰，制备了电化学传感器CCF 1.5} /SPCE，由于其良好的导电性、足够的表面活性位点和高效的催化作用，该传感器对唾液UA表现出灵敏和选择性的响应活动。人工唾液中 UA 的测定实现了 40 nM–30 μM 的宽线性范围和 15.3 nM (3 σ / s of 3)的检测下限 (LOD) 。传感器的性能，包括其再现性、稳定性和选择性，估计是令人满意的。测定人唾液中UA的含量，回收率为98%~107%，总RSD为4.14%。结果证实了CCF _1.5 /SPCE应用于无创检测的可靠性。