Department of Civil and Environmental Engineering, University of Massachusetts Lowell, One University Ave., Lowell, MA, 01854, USA.
US Army Combat Capabilities Development Command Soldier Center (CCDC SC), General Greene Ave, Natick, MA, 01760, USA.
Anal Bioanal Chem. 2020 Jul;412(17):4113-4125. doi: 10.1007/s00216-020-02642-4. Epub 2020 Apr 16.
The present work reports a newly developed square wave anodic stripping voltammetry (SWASV) methodology using novel gold nanostar-modified screen-printed carbon electrodes (AuNS/SPCE) and modified Britton-Robinson buffer (mBRB) for simultaneous detection of trace cadmium(II), arsenic(III), and selenium(IV). During individual and simultaneous detection, Cd, As, and Se exhibited well-separated SWASV peaks at approximately - 0.48, - 0.09, and 0.65 V, respectively (versus Ag/AgCl reference electrode), which enabled a highly selective detection of the three analytes. Electrochemical impedance spectrum tests showed a significant decrease in charge transfer resistance with the AuNS/SPCE (0.8 kΩ) compared with bare SPCE (2.4 kΩ). Cyclic voltammetry experiments showed a significant increase in electroactive surface area with electrode modification. The low charge transfer resistance and high electroactive surface area contributed to the high sensitivity for Cd (0.0767 μA (0.225 μg L)), As (0.2213 μA (μg L)), and Se (μA (μg L)). The three analytes had linear stripping responses over the concentration range of 0 to 100 μg L, with the obtained LoD for Cd, As, and Se of 1.6, 0.8, and 1.6 μg L, respectively. In comparison with individual detection, the simultaneous detection of As and Se showed peak height reductions of 40.8% and 42.7%, respectively. This result was associated with the possible formation of electrochemically inactive arsenic triselenide (AsSe) during the preconcentration step. Surface water analysis resulted in average percent recoveries of 109% for Cd, 93% for As, and 92% for Se, indicating the proposed method is accurate and reliable for the simultaneous detection of Cd, As, and Se in real water samples. Graphical abstract.
本工作报道了一种新开发的方波阳极溶出伏安法（SWASV）方法，使用新型金纳米星修饰的丝网印刷碳电极（AuNS/SPCE）和改良的 Britton-Robinson 缓冲液（mBRB），用于痕量镉（II）、砷（III）和硒（IV）的同时检测。在单独和同时检测中，Cd、As 和 Se 在约-0.48、-0.09 和 0.65 V 处分别显示出良好分离的 SWASV 峰（相对于 Ag/AgCl 参比电极），这使得对三种分析物进行了高选择性检测。电化学阻抗谱测试表明，与裸 SPCE（2.4 kΩ）相比，AuNS/SPCE（0.8 kΩ）的电荷转移电阻显著降低。循环伏安实验表明，电极修饰后电活性表面积显著增加。低电荷转移电阻和高电活性表面积有助于 Cd（0.0767 μA（0.225 μg L））、As（0.2213 μA（μg L））和 Se（μA（μg L））的高灵敏度。三种分析物在 0 至 100 μg L 的浓度范围内具有线性溶出响应，Cd、As 和 Se 的检出限分别为 1.6、0.8 和 1.6 μg L。与单独检测相比，As 和 Se 的同时检测的峰高分别降低了 40.8%和 42.7%。这一结果与预浓缩步骤中可能形成电化学惰性砷三硒化物（AsSe）有关。对地表水的分析结果表明，Cd 的平均回收率为 109%，As 的回收率为 93%，Se 的回收率为 92%，表明该方法可用于实际水样中 Cd、As 和 Se 的同时检测，结果准确可靠。
