Determination of chromium(VI) by differential-pulse polarography with a sodium fluoride supporting electrolyte
- 1 January 1984
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in The Analyst
- Vol. 109 (7) , 927-930
- https://doi.org/10.1039/an9840900927
Abstract
The polarographic determination of Cr(VI) is usually performed in a sodium hydroxide, ammonium tartrate or ammonium acetate supporting electrolyte. This study suggests that 0.2 M sodium fluoride solution is a superior medium for trace level determinations. With differential-pulse polarography, the sensitivity in this medium is 0.64 nA (nmol l–1)–1 Cr(VI) at the 10–8 M level, and the detection limit is 1.6 × 10–8 M Cr(VI). With 1 × 10–7 M Cr(VI), 10-fold excesses of Fe(III), Cl– and NO3 – do not change the current by more than 4%; Cu(II) causes an 8% decrease. The presence of Fe(III), Cu(II) and Cl– causes significant error with ammonium acetate and ammonium tartrate electrolytes.Keywords
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