Anodic stripping voltammetric measurement of trace cadmium at antimony film modified sodium montmorillonite doped carbon paste electrode

• A Sb film modified montmorillonite doped carbon paste electrode is fabricated.
• The electrode exhibits remarkable analytical performance for Cd(II) in SWASV.
• Montmorillonite can assist signal amplification and improve the sensitivity.
• A sensitive and stable method for detection of Cd(II) is developed.

In this work, a simple and reliable electrochemical method for the determination of cadmium using an antimony film modified sodium montmorillonite (NaMM) doped carbon paste electrode (Sb/NaMM-CPE) was described. Due to the strong cation exchange ability and adsorptive characteristics of NaMM and excellent electroanalytical performance of the antimony film, the new electrode significantly enhanced the sensitivity for detection of Cd(II) and exhibited superior performance in comparison with the bare carbon paste electrode, antimony film modified carbon paste electrode (Sb/CPE), and NaMM modified carbon paste electrode (NaMM-CPE). Some parameters such as the composition of the paste, pH of the measure solution, the Sb(III) concentration, deposition time, and deposition potential that influenced the response of cadmium were investigated and the procedure was optimized for cadmium determination. This electrode, combined with square-wave anodic stripping voltammetry, displayed excellent linear behavior in the examined concentration range of 4.0–150.0 μg L−1 Cd(II) (R2 = 0.998) with a detection limit of 0.25 μg L−1. The Sb/NaMM-CPE was successfully applied to the determination of cadmium ion in tap water sample.

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