Simultaneous voltammetric detection of cadmium(II), arsenic(III), and selenium(IV) using gold nanostar–modified screen-printed carbon electrodes and modified Britton-Robinson buffer

• Published in: Analytical and bioanalytical chemistry 2020-07, Vol.412 (17), p.4113-4125
• Main Authors: Lu, Dingnan, Sullivan, Connor, Brack, Eric M., Drew, Christopher P., Kurup, Pradeep
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Anodic stripping; Arsenic; Arsenic ions; Arsenic triselenide; Biochemistry; Buffers; Cadmium; Carbon; Characterization and Evaluation of Materials; Charge transfer; Chemistry; Chemistry and Materials Science; Electrochemistry; Electrodes; Food Science; Gold; Laboratory Medicine; Monitoring/Environmental Analysis; Research Paper; Selenium; Silver chloride; Square waves; Surface area; Surface water; Voltammetry; Water analysis; Water sampling
• ISSN: 1618-2642; 1618-2650
• DOI: 10.1007/s00216-020-02642-4

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 2+ , As 3+ , and Se 4+ 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 2+ (0.0767 μA (0.225 μg L −1 ) −1 ), As 3+ (0.2213 μA (μg L −1 ) −1 ), and Se 4+ (μA (μg L −1 ) −1 ). The three analytes had linear stripping responses over the concentration range of 0 to 100 μg L −1 , with the obtained LoD for Cd 2+ , As 3+ , and Se 4+ of 1.6, 0.8, and 1.6 μg L −1 , respectively. In comparison with individual detection, the simultaneous detection of As 3+ and Se 4+ showed peak height reductions of 40.8% and 42.7%, respectively. This result was associated with the possible formation of electrochemically inactive arsenic triselenide (As 2 Se 3 ) during the preconcentration step. Surface water analysis resulted in average percent recoveries of 109% for Cd 2+ , 93% for As 3+ , and 92% for Se 4+ , indicating the proposed method is accurate and reliable for the simultaneous detection of Cd 2+ , As 3+ , and Se 4+ in real water samples. Graphical abstract