Capillary electrophoresis interfaced to inductively coupled plasma mass spectrometry for element selective detection in arsenic speciation

A method is presented to separate and detect six arsenic species by capillary electrophoresis (CE) interfaced to inductively coupled plasma mass spectrometry (ICP-MS). CE was used as a highly resolving separation system, whereas ICP-MS served as an element selective detector providing low detection limits. The special mode of operation included sample stacking and a differentiation of separation and detection. This provided separation and detection of six As species, uncharged and anionic, to be monitored within a single run. Detection limits were calculated according to IUPAC recommendation at 15 microg As/L for As (III), dimethyl arsinic acid (DA), monomethyl arsonic acid (MA) and As (V), or 65 microg As/L for arsenobetaine (AsB) and arsenocholine (AsC). Investigations were focused on possibly occurring interferences, e.g., ArCl+ interference at the monoisotope 75As. Finally, real samples from biomedical field (urine) and environmental field (sewage sludge) were analyzed.