建立了高效液相色谱-电感耦合等离子体质谱法同时测定淡水中亚砷酸盐[As（Ⅲ）]、砷酸盐[As（Ⅴ）]、一甲基胂酸（MMA）、二甲基胂酸（DMA）、亚硒酸盐[Se（Ⅳ）]、硒酸盐[Se（Ⅵ）]和六价铬[Cr（Ⅵ）]的方法。采用以不同体积比的pH 8.7的20 mmol·L^-1硝酸铵溶液和pH 8.7的60 mmol·L^-1硝酸铵溶液为流动相进行梯度洗脱，通过优化的色谱条件实现了7种元素形态在14 min完成色谱分离，氯化物对⁷⁵As、⁷⁷Se、⁵³Cr无干扰。7种元素形态在一定范围内呈线性，As（Ⅲ）、As（Ⅴ）、MMA、DMA、Se（Ⅳ）、Se（Ⅵ）和Cr（Ⅵ）的检出限（3S/N）分别为0.06，0.02，0.04，0.05，1.00，1.00，0.20 μg·L^-1。按标准加入法进行回收试验，回收率为80.1%~101%，相对标准偏差（n=6）为0.59%~5.2%。

A method was proposed for simultaneous determination of arsenite[As(Ⅲ)], arsenate[As(Ⅴ)], monomethylarsenic acid (MMA), dimethylarsenic acid (DMA), selenite[Se(Ⅳ)], selenate[Se(Ⅵ)] and Cr(Ⅵ) in fresh water by high performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS). A mixture of 20 mmol·L^-1 NH₄NO₃ solution (pH 8.7) and 60 mmol·L^-1 NH₄NO₃ solution (pH 8.7) in different volume ratios was used as the mobile phase for gradient elution. Seven element species were separated under the optimized chromatographic conditions within 14 min, and the chloride had no interference to ⁷⁵As, ⁷⁷Se and ⁵³Cr. Linear relationships of 7 element species were found in definite ranges, and the detection limits were 0.06 μg·L^-1 for As (Ⅲ), 0.02 μg·L^-1 for As(Ⅴ), 0.04 μg·L^-1 for MMA, 0.05 μg·L^-1 for DMA, 1.00 μg·L^-1 for Se(Ⅳ), 1.00 μg·L^-1 for Se(Ⅵ) and 0.20 μg·L^-1 for Cr(Ⅵ), respectively. Test for recovery was made by standard addition method, giving results in the range of 80.1%-101%, with RSDs (n=6) ranged from 0.59% to 5.2%.