Off-line coupling of capillary electrophoresis to inductively coupled plasma mass spectrometry for elemental speciation
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| Year of publication | 2008 |
| Type | Conference abstract |
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| Description | Forms of metals differentiated by oxidation state or bound ligands differ remarkably in the impact on their physiological function. On-line combination of column separation techniques, such as capillary electrophoresis (CE) or high performance liquid chromatography (HPLC), to inductively coupled plasma mass spectrometry ICP MS belongs to the most powerful tools for elemental speciation. It is usually achieved using nebulizers or direct injection interfaces. When combined with CE, these techniques can reduce separation resolution due to induced liquid flow in the separation column. Here we report the first off-line coupling of capillary electrophoresis with ICP MS, which is based on effluent deposition on a suitable target followed by laser ablation (LA) and transfer into ICP. The technique is compatible with microcolumn separations in terms of preservation both separation resolution and sensitivity. Furthermore, the fractions collected on the target can be archived and analyzed using other detection techniques. Effect of laser fluence and substrate type on the results will be discussed. Use of an absorbing substrate (PETG) allowed reduction of the laser fluence needed for the ablation of the deposited samples. The detection limits of Cr, Cu, Co, Fe, Ni, Sn and Zn deposited on the target were in the subpicomolar range. Chromium was selected as a model analyte for investigation of the ablation process and demonstration of elemental speciation. Two-minute CE - LA ICP MS speciation of 10 pg of Cr(III) and Cr (VI) will be presented; peak halfwidths of as low as 3 seconds were obtained. |
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