Ficklin W H
U.S. Geological Survey, Box 25046, Denver, CO 80225, U.S.A.
Talanta. 1983 May;30(5):371-3. doi: 10.1016/0039-9140(83)80084-8.
The predominant species of arsenic in ground water are probably arsenite and arsenate. These can be separated with a strong anion-exchange resin (Dowex 1 x 8; 100-200 mesh, acetate form) in a 10 cm x 7 mm column. Samples are filtered and acidified with concentrated hydrochloric acid (1 ml per 100 ml of sample) at the sample site. Five ml of the acidified sample are used for the separation. At this acidity, As(III) passes through the acetate-form resin, and As(V) is retained. As(V) is eluted by passage of 0.12M hydrochloric acid through the column (resulting in conversion of the resin back into the chloride form). Samples are collected in 5-ml portions up to a total of 20 ml. The arsenic concentration in each portion is determined by graphite-furnace atomic-absorption spectrophotometry. The first two fractions give the As(III) concentration and the last two the As(V) concentration. The detection limit for the concentration of each species is 1 mug l .
地下水中砷的主要存在形式可能是亚砷酸盐和砷酸盐。它们可以在一个10厘米×7毫米的柱中用强阴离子交换树脂（Dowex 1 x 8；100 - 200目，醋酸盐形式）进行分离。样品在采样现场过滤并用浓盐酸（每100毫升样品加1毫升）酸化。取5毫升酸化后的样品用于分离。在此酸度下，As(III)通过醋酸盐形式的树脂，而As(V)被保留。通过用0.12M盐酸通过柱子洗脱As(V)（使树脂转化回氯化物形式）。以5毫升的份数收集样品，总量达20毫升。通过石墨炉原子吸收分光光度法测定每份样品中的砷浓度。前两份馏分给出As(III)的浓度，后两份给出As(V)的浓度。每种形态浓度的检测限为1微克/升。
