Chemical speciation of arsenic in serum of uraemic patients†

Abstract

Chemical speciation of arsenic was carried out in serum of a total of 51 uraemic patients: 19 non-dialysis (ND), 18 haemodialysis (HD) and 14 continuous ambulatory peritoneal dialysis (CAPD) patients. The low molecular mass As species were separated by ion-exchange liquid chromatography and measured on-line by hydride generation atomic absorption spectrometry (HGAAS). The high molecular mass As species were separated by fast protein liquid chromatography, either size-exclusion, ion-exchange or affinity chromatography, and the fractions were digested and measured off-line with HGAAS. The mean total As concentrations in the serum of the three groups of the uraemic patients were significantly higher than the reference value (6.47 ± 4.28, 5.12 ± 5.58 and 4.67 ± 5.41 µg l^–1 for HD, ND and CAPD patients, respectively, versus the reference value of 0.96 ± 1.52 µg l^–1). The major As species in serum of the patients were dimethylarsinic acid (DMA) and arsenobetaine. The HD patients showed a significantly higher mean DMA level than ND and CAPD patients. No selective removal of different As species in serum of HD patients was observed after 4 h of haemodialysis. The inorganic As species in serum were bound to proteins, mainly transferrin (about 5–6% of total As in serum). This binding may play an important role in arsenic detoxification.