Jay Jenny Ayla, Keon Blute Nicole, Hemond Harold F, Durant John L
Civil and Environmental Engineering Department, University of California Los Angeles, 5732H Boelter Hall, Los Angeles, CA 90095-1593, USA.
Water Res. 2004 Mar;38(5):1155-8. doi: 10.1016/j.watres.2003.11.014.
A field-portable anion exchange resin method (often cited as the Ficklin method (1983)) has been extensively used to distinguish between dissolved arsenite (As(III)) and arsenate (As(V)) species in natural waters. As(III) occurs largely as As(OH)(3), which is uncharged at ca. pH 7, while As(V) is negatively charged and will sorb to the resin. However, we show that negatively charged As(III)-sulfide (thioarsenite) species, important at sulfide concentrations >10 microM, also bind to the anion exchange resins, and therefore might be interpreted incorrectly as As(V). Furthermore, we show that nitrogen-purging, which results in a conversion of As(III)-sulfides to arsenite, can be used to obtain accurate arsenic speciation when resins are used on sulfidic water samples.
一种现场便携式阴离子交换树脂法（常被称为菲克林法（1983年））已被广泛用于区分天然水中溶解的亚砷酸盐（As(III)）和砷酸盐（As(V)）物种。As(III)主要以As(OH)(3)的形式存在，在约pH 7时呈电中性，而As(V)带负电荷并会吸附到树脂上。然而，我们发现带负电荷的As(III)-硫化物（硫代亚砷酸盐）物种在硫化物浓度>10 microM时很重要，它们也会与阴离子交换树脂结合，因此可能会被错误地解释为As(V)。此外，我们表明，当对含硫化物的水样使用树脂时，通过氮气吹扫将As(III)-硫化物转化为亚砷酸盐，可用于获得准确的砷形态分析结果。
