Simultaneous Speciation Analysis of Inorganic Arsenic and Antimony by On-Line Microwave-Assisted Oxidation and Hydride Generation-Atomic Fluorescence Spectrometry

Fast simultaneous speciation analysis of inorganic arsenic and antimony was achieved by using on-line microwave-assisted oxidation and hydride generation-atomic fluorescence spectrometry (HG-AFS). Without microwave irradiation, As(III) and Sb(III) can be selectively determined in acetic acid/sodium acetate (HAc/NaAc) buffer solution at pH 4.3 with 2% potassium tetrahydroborate (KBH4) as the reductant. Under microwave irradiation, the on-line oxidation of As(III) and Sb(III) to As(V) and Sb(V), respectively, can be accomplished within 5 s in the presence of 0.1 mol L-1 potassium peroxydisulfate (K2S2O8). Then, total As or Sb concentration was determined in 6% HCl and 4% KBH4 solution. Consequently, the As(V) and Sb(V) concentrations can be calculated by subtracting As(III) and Sb(III) concentrations from the total As and Sb concentrations, respectively. The limits of detection (LOD) for As(III), Sb(III), total As and total Sb were found to be 0.02 mu g L-1, 0.02 mu g L-1, 0.07 mu g L-1,and 0.08 mu g L-1, respectively.