Adsorptive Stripping Voltammetric Measurements of Trace Molybdenum at the Bismuth Film Electrode

✍ Scribed by Joseph Wang; Sompong Thongngamdee; Donglai Lu

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 325 KB
• Volume: 18
• Category: Article
• ISSN: 1040-0397
• DOI: 10.1002/elan.200503358

✦ Synopsis

Abstract

Bismuth‐film electrodes on glassy‐carbon substrates have been successfully applied for adsorptive‐stripping voltammetric measurements of trace molybdenum in the presence of chloranilic acid (CAA). The procedure is based on the preconcentration of the molybdenum‐chloranilic acid complex at a preplated bismuth film electrode held at −0.55 V (vs. Ag/AgCl), followed by a negatively‐sweeping square‐wave voltammetric scan. Factors influencing the adsorptive stripping performance, including different ligands, solution pH, CAA concentration, preconcentration time and potential, have been optimized. The response compares favorably with that observed at mercury film electrodes, and is linear over the 5–50 μg/L Mo concentration range (one min preconcentration). A detection limit of 0.2 μg/L molybdenum is obtained following a 10 min accumulation. High stability is indicated from the reproducible response of a 100 μg/L molybdenum solution (n= 60; RSD=2.6%). Applicability to seawater samples is demonstrated.