Seoul Center, Korea Basic Science Institute, 126-16 5th Street, Anamdong, Sungbukgu, Seoul 136-713, Republic of Korea.
J Hazard Mater. 2013 Sep 15;260:24-31. doi: 10.1016/j.jhazmat.2013.04.033. Epub 2013 Apr 30.
Dimethylarsinic acid (DMA(V)) was pre-concentrated from water samples using a strong cation exchange (SCX) disk functionalized with sulfonic groups, before being analyzed by wavelength dispersive X-ray fluorescence spectrometry (WDXRF). The adsorption of DMA(V) occurred preferentially on the surface of the SCX disk, regardless of pH levels, probably due to interactions with the sulfonic functional groups. However, no other arsenic species, such as arsenate (iAs(V)), arsenite (iAs(III)), and monomethylarsonic acid (MMA(V)), were retained. The SCX-WDXRF method produced a strongly linear calibration curve (R(2)=0.9996) with its limit of detection at 0.218 μgL(-1) when a one-liter water sample was used for pre-concentration. The As intensity of the system was sensitive to the Pb content retained on the SCX disk owing to the proximity of the As-Kα and Pb-Lα lines. To compensate for this interference, a correction factor was developed by considering the calibration slope ratio between the X-ray intensity measured at a Bragg angle of 48.781° and the Pb content of the SCX disks. The results of spike tests for iAs(V), iAs(III), MMA(V), and DMA(V) with and without the addition of Pb in synthetic landfill leachate exhibited reasonable recoveries (i.e., 98-105%) after the spectral adjustment for the Pb interference.
二甲砷酸（DMA(V)）先用磺酸基功能化的强阳离子交换（SCX）圆盘从水样中预浓缩，然后用波长色散 X 射线荧光光谱法（WDXRF）分析。DMA(V)的吸附优先发生在 SCX 圆盘的表面上，而与 pH 值无关，这可能是由于与磺酸功能基团的相互作用。然而，没有其他砷物种，如砷酸盐（iAs(V)）、亚砷酸盐（iAs(III)）和一甲基砷酸（MMA(V)）被保留。SCX-WDXRF 方法在使用 1 升水样进行预浓缩时，产生了一条具有强烈线性校准曲线（R(2)=0.9996），其检测限为 0.218 μgL(-1)。由于 As-Kα 和 Pb-Lα 线的接近，系统的 As 强度对保留在 SCX 圆盘上的 Pb 含量很敏感。为了补偿这种干扰，通过考虑在布拉格角 48.781°处测量的 X 射线强度与 SCX 圆盘的 Pb 含量之间的校准斜率比，开发了一个校正因子。对于含有和不含有 Pb 的合成垃圾渗滤液中的 iAs(V)、iAs(III)、MMA(V)和 DMA(V)的加标测试，在对 Pb 干扰进行光谱调整后，显示出合理的回收率（即 98-105%）。
