[Speciation analysis of manganese in water sample using flame atomic absorption spectrometry with hydrolysis...

A rapid and sensitive method for the sequential determination of Mn(II), Mn (lV) and Mn( VII) in water samples based on flame atomic absorption spectrometry with hydrolysis separation system has been developed. In the proper acidity, the manganese in different kind of speciation was separated by using hydrolysis acidity. The pH of sample containing manganese in different kind of speciation was adjusted to 10 by using NaOH solution, and at pH 10 of the medium, Mn( II) and M(IV) were precipitated as hydrolysis precipitation, while Mn(VII) remaining in the solution was determined by AAS. After that, hydrolysis precipitation of Mn( II) was solvated by adding sulfuric acid with pH 5 as solvent and determined by AAS. Finally, hydrolysis precipitation of Mn(IV) was solvated by adding sulfuric acid with pH 1 as solvent and determined by AAS. The recoveries are 93. 3%-99. 5% for Mn( II), 96. 7%-103% for Mn(IV) and 98. 2%-104% for Mn(VII), the relative standard deviations are 2. 7%, 3. 2% and 3. 1% respectively, and the detection limits are 0. 10 mg x L(-1).