Gold nanostar-based voltammetric sensor for chromium(VI)
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This paper presents an electrochemical sensor for Cr(VI) (chromate ion) in water. A disposable screen-printed electrode was modified with gold nanostars (AuNSs) that were synthesized by Good’s buffer method. Linear sweep voltammetry (LSV) was employed for the detection of Cr(VI) in 0.1 M sulfuric acid solution. The AuNSs are shown to provide higher current response to Cr(VI) than spherically shaped gold nanoparticles. The sensor gives the strongest response at a scan rate of 0.05 V (vs Ag/AgCl) and exhibits minimal interference from other electroactive species. The linear range extends from 10 to 75,000 ppb, and the limit of detection is 3.5 ppb. This is well below the provisional guideline value given by the World Health Organization. Excellent recoveries (ranging between 95 and 97%) were found when analyzing contaminated ground water samples obtained from a site situated in Wellesley, MA.
KeywordsHeavy metals Ground water analysis Linear sweep voltammetry Carbon paste screen-printed electrode Nanoparticle Monitoring wells Star-shaped nanoparticle
This work was supported by the National Science Foundation award # 1543042. Any opinions, findings, and conclusions or recommendations expressed in this paper are those of the researchers and do not necessarily reflect the views of the funding agency. The authors would like to thank Dr. Earl Ada for performing the TEM imaging. The authors acknowledge Mr. John Fitzgerald (MassDEP), and two graduate students Connor Sullivan and Michaela Fitzgerald for sampling water from groundwater monitoring wells located in Wellesley, MA.
Compliance with ethical standards
The author(s) declare that they have no competing interests.
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