Speciation of six arsenic compounds using capillary electrophoresis-inductively coupled plasma mass spectrometry

Abstract

Capillary electrophoresis (CE) was used to separate four anionic {arsenite [As()], arsenate [As()], monomethylarsonic acid and dimethylarsinic acid } and two cationic forms (arsenobetaine and arsenocholine) of As in a single run. At sufficiently high concentrations, the determination of these compounds could be accomplished by means of UV detection. The determination of low concentrations (<10 mg l−1) of these compounds of interest was accomplished by coupling CE on-line with inductively coupled plasma mass spectrometry (ICP-MS ). To accomplish this coupling, a microconcentric nebulizer was used. The modifications necessary to make a conventional CE system compatible with ICP-MS, the optimization of the operation parameters and of sample stacking conditions together with the effect of the sheath liquid and of an induced laminar flow are discussed. The analytical figures of merit of the method were assessed and the limit of determination (based on the peak height of a peak for which the signal-to-noise ratio is 1051) was found to be 1-2 mg l−1 As for each species. The recovery for the compounds of interest was determined using a spiked mineral water sample. Samples of mineral water, soil leachate and urine were analyzed with the CE-ICP-MS combination. plasma. Furthermore, since concentric nebulizers are self-

Speciation of five arsenic species (arsenite, arsenate, MMAAV, DMAAV and AsBet) in different kind of water by HPLC-ICP-MS

“…However, as reported previously in literature (Van Holderbeke et al, 1999) commercially available natural mineral water exceeded this limit of 10 lg l À1 .…”

“…Depending on the geological origin of the natural mineral water, the arsenic content was very variable from one type of water to the other (Table 4). According to Van Holderbeke et al (1999), arsenic in such samples was exclusively in the arsenate form. Nevertheless, it was very interesting to notice that some natural mineral waters had a total arsenic content exceeding the 10 lg l À1 limit of the European Commission Directive 2003/40/CE (2003.…”

“…Numerous instrumental methods for these five arsenic species speciation are reported in the literature. Most of them are based on chromatographic separation techniques such as High Performance Liquid Chromatography (HPLC) (Gailer and Irgolic, 1996;Teräsahde et al, 1996;Le and Ma, 1997;Dagnac et al, 1999;Kohlmeyer et al, 2002) or Capillary Zone Electrophoresis (Van Holderbeke et al, 1999), coupled with a selective and sensitive detector such as Atomic Absorption Spectrometry (AAS) (Gailer and Irgolic, 1996) or Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) (Teräsahde et al, 1996;Kohlmeyer et al, 2002). Post column derivatization of arsenic species with formation of the volatile arsine hydrides, has been coupled with AAS (Le and Ma, 1997), Atomic Fluorescence Spectrometry (Simon et al, 2004) or ICP-MS (Dagnac et al, 1999), but cannot be used for quantifying AsBet without prior chemical conversion (Slejkovec et al, 1999).…”

CZE for the speciation of arsenic in aqueous soil extracts

“…The coupling of CE and inductively coupled plasma mass spectrometry (ICP-MS) is complicated because a low dead-volume interface is needed with flow rates ,0.5 mL/min [16]. Rosal et al [12] and Van Holderbeke et al [17] described the determination of roxarsone and its transformation products by CE coupled to ICP-MS. Organic solvent modification was successfully applied by Gil et al [10] to decrease the conductivity of synthetic aqueous samples and to make them suitable for the determination with CZE.…”

Fast separations by capillary electrophoresis hyphenated to electrospray ionization time-of-flight mass spectrometry as a tool for arsenic speciation analysis

“…The main advantages include its low buffer consumption, high resolution power and low sample requirement. CE has been successfully employed for arsenic speciation analysis [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] with its focus on elemental speciation analysis and the determination of inorganic species and the methylated arsenic acids (e.g., DMA, monomethylarsonic acid). AsB, AsC and phenylarsenic species (e.g., roxarsone) were frequently included in those studies.…”