Capillary electrophoresis with inductively coupled plasma-mass spectrometric and electrospray time of flight mass spectrometric detection for the determination of arsenic species in fish samples

CE was coupled to inductively coupled plasma MS (ICP-MS) and ESI-MS to identify and quantify the arsenic species arsenobetaine (AsB), arsenite (AsIII), arsenate (AsV), and dimethylarsinic acid (DMA). A GC-flame ionization detector (FID)-based German standard method and ICP-MS were used for validation of the data obtained for arsenobetaine and total arsenic, respectively. LODs obtained with the CE-ESI-TOF-MS method were 1.0x10⁻⁷ M for AsB, 5.0x10⁻⁷ M for DMA, and 1.0x10⁻⁶ M for AsIII and AsV. For the CE-ICP-MS method, LODs were 8.5x10⁻⁸ M for AsB, 9.5x10⁻⁸ M for DMA, 9.3x10⁻⁸ M for AsIII, and 6.2x10⁻⁸ M for AsV. While CE-ICP-MS provided high sensitivity and better reproducibility for quantitative measurements, CE-ESI-MS with a TOF mass analyzer proved to be valuable for species identification. With this setup, fish samples were prepared and analyzed and the obtained data were successfully validated with the independent methods.