Figure 7: Arsenic speciation standard chromatogram.

Chromatograms obtained for standard calibration solutions at 1, 10 and 50 μg/ L. Calibration of arsenate (AsV), methylarsonate (MA), dimethylarsinate (DMA) and arsenobetaine (AB) was performed with mixed solutions of arsenic (V) oxide hydrate (As2O5·xH2O), monomethylarsonic acid ((CH3AsO(OH)2), dimethylarsinic acid ((CH3)2AsO(OH)) and arsenobetaine ((CH3)3As + CH2COO-) respectively. Calibration of arsenite (AsIII) has been plotted simultaneously and was achieved with separate solutions of arsenic trioxide (As2O3).