Method development for the determination of mercury(II) by sequential injection/anodic stripping voltammetry using an in situ gold-film screen-printed carbon electrode

Eakkasit Punrat, Suchada Chuanuwatanakul, Takashi Kaneta, Shoji Motomizu, Orawon Chailapakul

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

A computer-controlled system, included a sequential injection system and an electrochemical detector, was developed for the determination of mercury(II) ion (Hg2+) concentrations. The screen-printed carbon electrode (SPCE), a well-known low-cost electrode, was modified by overlaying in situ with a gold film (Au-SPCE). Square wave anodic stripping voltammetry (SWASV) using the Au-SPCE was performed with a two-step deposition potential of an initial -0.5 V vs Ag/AgCl for the preparation of the gold film and then a deposition potential of +0.2 V vs Ag/AgCl for the preconcentration of mercury. An on-line medium exchange method was included in the injection step to reduce the effect of chloride ions, whilst a solid phase extraction cartridge was used to remove interference for copper(II) ions. The flow pattern of the sequentially injected solutions with the synchronized two-step deposition potentials did not significantly affect the detection of Hg2+. Square wave parameters of a 4 mV step potential, 150 Hz frequency and 30 mV amplitude gave an optimal Hg2+ detection sensitivity with a limit of detection of 0.22 μg L-1 (sample volume of 0.9 mL) without any significant interference effect. This method was successfully applied to determine Hg2+ concentrations in real water samples, including in the chloride-rich samples of sea water and table salt, with very good accuracy (recovery in the range of 96.0-101%).

Original languageEnglish
Pages (from-to)78-83
Number of pages6
JournalJournal of Electroanalytical Chemistry
Volume727
DOIs
Publication statusPublished - Aug 1 2014

Keywords

  • Mercury determination
  • On-line medium exchange
  • Screen-printed carbon electrode
  • Sequential injection analysis
  • Square-wave anodic stripping voltammetry

ASJC Scopus subject areas

  • Analytical Chemistry
  • Chemical Engineering(all)
  • Electrochemistry

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