H. Gurleyuk et D. Wallschlager, Determination of chromium(III) and chromium(VI) using suppressed ion chromatography inductively coupled plasma mass spectrometry, J ANAL ATOM, 16(9), 2001, pp. 926-930
We have developed a method for the determination of Cr(III) and Cr(VI) by i
on chromatography inductively coupled plasma mass spectrometry (IC-ICP-MS)
using a self-regenerating suppressor. Deposition of the dissolved solids on
the cones and the ion optics was eliminated by the Suppressor. Chromium(II
I) Wits derivatized with EDTA, forming a stable mono-anionic complex, which
wits then separated from Cr(VI) by anion-exchange chromatography. The cond
itions for the quantitative conversion or Cr(III) to the corresponding EDTA
complex were optimized and neither oxidation of Cr(III) to Cr(VI) nor redu
ction Or Cr(VI) to Cr(III) were observed. Using 50 mmol L-1 NH4NO3 (pH 8) a
s the chromatographic eluent, potential interferents, Such as chloride, car
bonate and sulfate, were separated from both the Cr(EDTA) complex and from
Cr(VI), and no salt deposition was observed over long periods of time. The
tolerance of the method to the presence of major matrix anions (NO3-, Cl-,
CO32- and SO42-) was extensively studied. With it 1 mL injection volume. th
e detection limits were 5 and 12 ng L-1 using Cr-52, and 7 and 16 ng L-1 us
ing Cr-53 for Cr(III) and Cr(VI). respectively. The RSD of 5 injections was
less than 5% at the 50 ng L-1 level. The method was validated using refere
nce materials SRM 1643d and SLEW-3.