Speciation of Chromium by LC-ICP-MS

A published LC-ICP-MS speciation method for Cr(III) and Cr(VI) was carried using customized RSpak NN column^*1. For this customized column, RSpak NN series gel was packed into 4.6 x 150 mm PEEK column housing instead of standard SUS housing. NN series packed gel is made from polyhydroxymethacrylate base modified with sulfo functional group. The main separation mode is reversed phase, but the addition of sulfo group provides ionic interaction effects. In this application, Cr(III) and Cr(VI) were analyzed according to the published method.


Sample : 5micro-g/L each, 25micro-L
1. Cr(III), Cr(NO₃)₃
2. Cr(VI), K₂CrO₄
Sample was first prepared by using 10mM nitric acid to make a 1 mg/L solution; and then it was diluted with mobile phase to the final concentration of 5micro-g/L.

Column       : Shodex *1NN-414 4D(4.6mmID*150mm) PEEK housing type can be prepared as a customized order
Eluent       : 90mM (NH4)2SO4 + 10mM NH4NO3(pH3.0 adjusted by HNO3)
Flow rate    : 0.3mL/min
Detector     : ICP/MS, Cr at m/z=52
Column temp. : 40℃

Reference:
Harald Hagendorfer, Walter Goessler.
Separation of chromium(III) and chromium(VI) by ion chromatography and an inductively coupled plasma mass spectrometer as element-selective detector.
Talanta. 2008, vol.76, p.656-661.