Capillary electrophoretic determination of As(V) and As(III) based on the formation of a Keggin-type [AsMo12O40]3– complex

✍ Scribed by Ken-Ichi Sano; Sadayuki Himeno

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 154 KB
• Volume: 25
• Category: Article
• ISSN: 1615-9306
• DOI: 10.1002/1615-9314(20020501)25:7<438::aid-jssc438>3.0.co;2-s

✦ Synopsis

Capillary electrophoretic determination of As(V) and As(III) based on the formation of a Keggin-type [AsMo 12 O 40 ] 3 -complex A novel capillary electrophoretic (CE) method was developed for the sensitive determination of As(V). In a 1610 -2 M (M = mol/dm 3 ) Mo(VI) -5610 -2 M HClO 4 -70% (v/v) CH 3 CN system, a trace amount of As(V) readily formed a mixture of a-and b-[AsMo 12 O 40 ] 3 -complexes. Since the electropherogram showed a sharp peak due to the migration of both complexes, the pre-column complex-formation reaction was applied to the sensitive CE determination of As(V) with direct UV detection at 220 nm. The peak area depended linearly on the concentration of As(V) in the range of 5610 -5 to 5610 -7 M, with a detection limit of 1610 -7 M (signal-to-noise ratio = 5). In a mixture of As(V) and As(III), As(III) could be determined after oxidation to As(V) with H 2 O 2 ; the As(III) content was estimated by subtracting the As(V) concentration before oxidation from the total arsenic concentration. Interferences from foreign ions were also discussed.