Yuan Xiaoming, Chen Linlin, Liu Ruwei, Li Shilin, Wu Xiu-Wen, Ling Yunhan
School of Science, China University of Geosciences, China; School of Materials Sciences and Engineering, Tsinghua University, China.
The Hospital of 82(ND) Group Army PLA, China.
Anal Chim Acta. 2025 Sep 22;1368:344365. doi: 10.1016/j.aca.2025.344365. Epub 2025 Jun 25.
Thiocyanate (SCN) poses dual health threats as both a toxic food additive in dairy products and a biomarker for tobacco smoke exposure in smokers' saliva. Existing detection platforms fail to simultaneously address the conflicting demands for high-sensitivity food analysis (0.1-10 ppm) and rapid point-of-care testing in biological fluids (50-200 μM). In this work, a dual-purpose portable electrochemical SCN sensor was developed based on a laser-induced graphene (LIG) composite electrode. The flexible and miniaturized graphene sensing platform was fabricated via UV laser patterning on polyimide substrates. Poly(3,4-ethylene dioxythiophene) (PEDOT) was functionally modified onto the electrode surface via in-situ electropolymerization, forming a conductive polymer-graphene hybrid composite electrode. Owing to the synergistic effects of LIG's outstanding physical properties and PEDOT's high conductivity, the composite electrode exhibited remarkable electrochemical performance for thiocyanate detection. Under optimized conditions, the sensor demonstrated a wide linear response range (10-300 μM), a high sensitivity of 3.06 μA μMcm, and a low detection limit of 0.52 μM (S/N = 3) through differential pulse voltammetry. Selective detection was achieved in complex matrices containing common interferents. Long-term stability tests revealed 94.2 % signal retention after two weeks of storage. Integrated with microfluidic sampling and a smartphone-based potentiostat, the handheld portable device enabled rapid SCN analysis within just 1 min. Practical validation using milk and artificial saliva samples showed recovery rates of 96.2-105.5 %, highlighting its potential for food safety inspection and health monitoring. This work provides a cost-effective (<$0.5) approach for field-deployable food safety systems and personalized health management.
硫氰酸盐（SCN）对健康构成双重威胁，它既是乳制品中的有毒食品添加剂，又是吸烟者唾液中烟草烟雾暴露的生物标志物。现有的检测平台无法同时满足高灵敏度食品分析（0.1 - 10 ppm）和生物体液中快速即时检测（50 - 200 μM）这两个相互冲突的需求。在这项工作中，基于激光诱导石墨烯（LIG）复合电极开发了一种两用便携式电化学SCN传感器。通过在聚酰亚胺基板上进行紫外激光图案化制备了柔性且小型化的石墨烯传感平台。聚（3,4 - 亚乙二氧基噻吩）（PEDOT）通过原位电聚合功能修饰在电极表面，形成导电聚合物 - 石墨烯混合复合电极。由于LIG优异的物理性能和PEDOT的高导电性的协同作用，复合电极在硫氰酸盐检测中表现出卓越的电化学性能。在优化条件下，该传感器通过差分脉冲伏安法显示出宽线性响应范围（10 - 300 μM）、3.06 μA μM⁻¹ cm⁻²的高灵敏度和0.52 μM的低检测限（S/N = 3）。在含有常见干扰物的复杂基质中实现了选择性检测。长期稳定性测试表明，储存两周后信号保留率为94.2%。与微流控采样和基于智能手机的恒电位仪集成，该手持式便携式设备能够在仅1分钟内实现快速SCN分析。使用牛奶和人工唾液样本的实际验证显示回收率为96.2 - 105.5%，突出了其在食品安全检测和健康监测方面的潜力。这项工作为可现场部署的食品安全系统和个性化健康管理提供了一种经济高效（<0.5美元）的方法。
