Quantitative studies of aluminium binding species in human uremic serum by fast protein liquid chromatography coupled with electrothermal atomic absorption spectrometry.

Fast protein liquid chromatography (FPLC) was used with electrothermal atomic absorption spectrometric (ETAAS) detection for quantitative studies of aluminium binding species in unspiked human uremic serum. A rapid and reproducible separation of human serum proteins and other aluminium binders (citrate and desferroxiamine) was achieved on a Mono Q (HR 5/5) anion-exchange column using a sodium chloride gradient (0-0.25 mol l-1) at the physiological human serum pH of 7.4 (0.05 mol l-1 buffer TRIS-HCl). The aluminium distribution in the column fractions was determined by ETAAS. Aluminium contamination was avoided by using an inert chromatographic system equipped with an on-line aluminium-chelating scavenger column (Kelex 100-impregnated silica C18). The sensitivity of the proposed method (detection limit for Al in serum = 5 micrograms l-1) allowed aluminium speciation studies at clinically relevant concentrations (unspiked serum from dialysis patients). The results obtained confirmed that transferrin is the only serum protein binding aluminium and it contains about 90% of total serum aluminium (post-elution aluminium recovery = 105 +/- 5%). It was also confirmed that in the presence of the chelating drug desferrioxamine (DFO) most of the serum aluminium (80%) is bound to DFO.