Speciation Of As³⁺, As⁵⁺, Monomethyl Arsonate (Mma) And Dimethyl Arsinate (Dma) In The Urine Of African Rat Using Exchange Chromatography

Abstract

A combined cation-anion exchange resin has been used to speciate a standard solution containing a mixture of As³⁺, 2.5 mg/kg As⁵⁺, 2.5 mg/kg MMA, and 2.5 mg/kg DMA. Recoveries were As³⁺: 96 ± 4 %, As⁵⁺: 92 ± 8 %, MMA: 91 ± 10 % and DMA: 104 ± 4 %. Using the combined resin, an African rat was ingested with 0.1 g sodium arsenite (As³⁺), and analysis of 2 mL of the urine containing 5.4 ± 0.3 mg/kg of total As, revealed the presence of As³⁺: 1.0 ± 0.2 mg/kg, As⁵⁺: 0.8 ± 0.1 mg/kg, MMA: 1.1 ± 0.4 mg/kg and 1.6 ± 0.4 mg/kg of DMA. A higher concentration of 0.2 g of the arsenite was given to the same rat, and analysis of 2 mL of the urine, indicated As species presence were total As: 7.6 ± 0.5 mg/kg, As³⁺: 0.16 ± 0.01 mg/kg, As⁵⁺: 6.8 ± 0.7 mg/kg, MMA: 0.5 ± 0.3 mg/kg and 1.4 ± 0.3 mg/kg of DMA. The study demonstrated that rats are capable of biotrans-forming As³⁺ into the As⁵⁺, MMA and DMA.

Journal of Applied Science and Technology Vol. 12 (1&2) 2007: pp.31-34