Interferences by transition metals and their elimination by cyanide as a complexing agent in the determination of arsenic using continuous flow HG-ICP-AES

Abstract

The interfering effects of various foreign ions on the determination of arsenic were studied by hydride generation inductively coupled plasma atomic emission spectrometry (HG-ICP-AES). There were serious inhibiting interferences by Cu, Pb, Co, Au, Pd and Ni. However, by using cyanide as a complexing agent these interferences could be completely eliminated over a wide range of interferent concentration. The optimum chemical parameters for continuous arsine generation were studied. A major advantage of this technique is that it only needs low acid concentrations and produces less hazardous waste. Sensivity, selectivity and accuracy of the determination of arsenic by HG-ICP-AES were investigated. The detection limit (in 1 mol/l HCl medium) for arsenic(III) was 0.82 ng/ml. The relative standard deviation for ten determinations of a solution containing 50 ng/ml arsenic was 1.3%.

On-line chemical vapour generation of cadmium in the presence of hexacyanochromate(iii) for determination by inductively coupled plasma mass spectrometry (ICP-MS)

“…KCN has been used for alleviating the interferences of Cu(II) and a number of transition metals (Au, Co, Cu, Pb, and Ni) in chemical vapour generation of Cd 6 and As. 23 Although its effectiveness in masking the interferences of numerous other transition metals in Cd vapour generation is not known, this improvement could be ascribed to partial masking of the interferences, especially from Bi(III) and Pb(II).…”

“…6,8,23,24 It also forms complexes with transition metal ions, such as Cr(III), Cu(II), Fe(II) and Fe(III). 25,26 The Fe(II) and Fe(III) complexes, Fe[(CN) 6 ] 4− and Fe[(CN) 6 ] 3− respectively, have been known as stable species for more than a century.…”

“…Potassium cyanide has been realized as an effective masking agent in alleviating the depressive effects of transition metals in chemical vapour generation. 6,8,23,24 It also forms complexes with transition metal ions, such as Cr(III), Cu(II), Fe(II) and Fe(III). 25,26 The Fe(II) and Fe(III) complexes, Fe[(CN) 6 ] 4À and Fe[(CN) 6 ] 3À respectively, have been known as stable species for more than a century.…”