Gold nanostar-based voltammetric sensor for chromium(VI).

Area of Science:

• Electrochemistry
• Nanomaterials Science
• Environmental Science

Background:

• Hexavalent chromium (Cr(VI)) is a toxic pollutant found in water sources.
• Accurate and sensitive detection methods for Cr(VI) are essential for environmental monitoring and public health.
• Existing methods may lack sensitivity, selectivity, or cost-effectiveness.

Purpose of the Study:

• To develop a novel electrochemical sensor for the sensitive detection of Cr(VI) in aqueous samples.
• To investigate the performance of gold nanostars (AuNSs) as a modifying agent for disposable screen-printed electrodes.
• To evaluate the sensor's applicability in real-world water samples.

Main Methods:

• Synthesis of gold nanostars (AuNSs) using Good's buffer method.
• Modification of disposable screen-printed electrodes with AuNSs via drop casting.
• Electrochemical detection of Cr(VI) using linear sweep voltammetry (LSV) in sulfuric acid solution.

Main Results:

• AuNS-modified electrodes exhibited enhanced current response for Cr(VI) detection compared to spherical gold nanoparticles.
• The sensor demonstrated optimal performance at a scan rate of 0.05 V (vs Ag/AgCl).
• A wide linear detection range (10–75,000 ppb) with a low limit of detection (3.5 ppb) was achieved, falling below WHO guidelines.
• High recovery rates (95–97%) were observed in real contaminated groundwater samples.

Conclusions:

• The developed AuNS-based electrochemical sensor is highly sensitive and selective for Cr(VI) detection.
• This sensor offers a promising, cost-effective, and disposable platform for environmental water quality monitoring.
• The findings support the use of AuNSs in electrochemical sensing applications for toxic metal ion detection.