Differential pulse adsorptive voltammetric determination of chromium in aluminum

✍ Scribed by K. M. Sarnaik; M. M. Palrecha; R. G. Dhaneshwar

• Publisher: John Wiley and Sons
• Year: 1989
• Tongue: English
• Weight: 287 KB
• Volume: 1
• Category: Article
• ISSN: 1040-0397
• DOI: 10.1002/elan.1140010516

✦ Synopsis

A method is presented for determining the trace amount of chromium in aluminum. Aluminum is dissolved in sodium hydroxide containing hydrogen peroxide. The method is based on the catalytic activity of nitrate ions on the reduction of Cr( 111)-triethylenetetraminehexaacetic acid (-'ITHA) complex. The sensitivity of this method is further improved by adsorptive preccncentration o f Cr(II1)-TTHA complex at a hanging mercury drop electrode (HMDE). The adsorbed complex is then reduced at a peak potential o f -1.28 V, and the peak height of Cr(II1) reduction is measured. The Cr(II1) formed at the electrode surface by the reduction of Cr(VI), which is present in the bulk solution, is immediately complexed by TTHA. This method is suitable for the determination of chromium at levels as low as 0.5 pg g-' (with about 25 mg o f sample) and a relative standard deviation of 15%.