Sequential determination of arsenite and arsenate by ion chromatography

✍ Scribed by Zong-li Li; Shi-fen Mou; Zhe-ming Ni; John M. Riviello

• Book ID: 102982515
• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 749 KB
• Volume: 307
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/0003-2670(95)00030-4

✦ Synopsis

A procedure for the sequential determination of arsenite [As(III)] and arsenate [As(V)] based on electrochemical detection for As(II1) and spectrophotometric detection for As(V) following ion chromatographic separation was developed. The color-developing system was based on the ion-association complex formed by heteropolymolybdoarsenic acid with bismuth in the presence of Triton X-100. Experimental conditions for electrochemical detection and color-developing conditions were optimized for A&II) and As(V), respectively. The optimal applied potential for electrochemical detection of As(II1) was + 0.35 V and the wavelength for spectrophotometric detection of As(V) was 700 nm. By using an eluent of 2.0 mM sodium hydrogencarbonate-mM sodium carbonate with a 175 ~1 sample loop for ion chromatographic separation, the detection limits, which are defined as the concentrations that give the peak intensity twice the baseline noise, are found to be 2.9 pg/l for As(II1) and 13 pg/l for As(V), respectively. The spiked waste water samples were analyzed and recoveries were found to be 97.5-104% for As(II1) and 93.5103%

for As(V), respectively.