Kitagawa Fumihiko, Shiomi Kazutaka, Otsuka Koji
Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Japan.
Electrophoresis. 2006 Jun;27(11):2233-9. doi: 10.1002/elps.200500614.
CE with indirect UV and mass-spectrometric detection was used for the simultaneous determination of arsenic acid (As(V)), arsenous acid (As(III)), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), trimethylarsine oxide (TMAO), tetramethylarsonium ion (TMA(+)), arsenobetaine (AB), and arsenocholine (AC). In the CE-indirect UV analysis, a baseline separation of arsenic species was successfully achieved by using a basic background solution (BGS) for anions and an acidic BGS for cations, respectively. The LOD values in CE-indirect UV for the individual analytes were 7.8, 12.5, 7.8, 12.5, 62.5, 125, 250, and 62.5 ppm, respectively. To achieve sensitive and selective analysis, CE coupled with ESI-MS was applied to the determination of arsenic compounds. The organic arsenic species were successfully separated with a higher sensitivity by CE-MS using the acidic BGS. The LODs in CE-MS for MMA, DMA, TMAO, TMA(+), AB, and AC were 1.0, 0.1, 0.01, 0.1, 0.01, and 0.01 ppm, respectively. In contrast, the analysis of inorganic arsenic species (As(V) and As(III)) resulted in a lower detectability in CE-MS compared to that obtained with the CE-indirect UV analysis. However, the speciation of eight arsenics by CE-MS was successfully achieved in a single run by switching the ESI polarity during MS detection.
采用带间接紫外和质谱检测的毛细管电泳法同时测定砷酸（As(V)）、亚砷酸（As(III)）、一甲基胂酸（MMA）、二甲基胂酸（DMA）、三甲基氧化胂（TMAO）、四甲基砷离子（TMA(+)）、砷甜菜碱（AB）和砷胆碱（AC）。在毛细管电泳 - 间接紫外分析中，分别使用阴离子碱性背景溶液（BGS）和阳离子酸性BGS成功实现了砷形态的基线分离。各分析物在毛细管电泳 - 间接紫外中的检测限分别为7.8、12.5、7.8、12.5、62.5、125、250和62.5 ppm。为实现灵敏且选择性的分析，将毛细管电泳与电喷雾电离质谱联用用于砷化合物的测定。通过使用酸性BGS的毛细管电泳 - 质谱成功以更高灵敏度分离了有机砷形态。毛细管电泳 - 质谱中MMA、DMA、TMAO、TMA(+)、AB和AC的检测限分别为1.0、0.1、0.01、0.1、0.01和0.01 ppm。相比之下，与毛细管电泳 - 间接紫外分析相比，无机砷形态（As(V)和As(III)）在毛细管电泳 - 质谱中的可检测性较低。然而，通过在质谱检测期间切换电喷雾电离极性，一次进样成功实现了毛细管电泳 - 质谱对八种砷的形态分析。
