This method is used to determine dissolved arsenite (As(III)), arsenate (As(V)), monomethylarsonate (MMA), and dimethylarsinate (DMA) in water including acid mine drainage. Addition of 2% (by volume) of methanol to the mobile phase also allows for the separation and determination of roxarsone.

This method includes modifications of a method described by Jackson and others (2000) for the separation and determination of arsenite (As(III)), arsenate (As(V)), monomethylarsonate (MMA), and dimethylarsinate (DMA) using high performance liquid chromatography with ICP-MS detection. Nitric acid is used as the mobile phase to chromatographically separate arsenic species making it possible to analyze acid mine drainage. 

Applicable Conc Range MDL to 100 µg/L

Detection limit:  0.2-0.3 µg/L (depending on species)