QUANTITATIVE STUDIES OF ALUMINUM 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 st udies of aluminium binding species in unspiked human uremic serum, A r apid and reproducible separation of human serum proteins and other alu minium binders (citrate and desferroxiamine) was achieved on a Mono Q (HR 5/5) anion-exchange column using a sodium chloride gradient (0-0.2 5 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-ch elating scavenger column (Kelex 100-impregnated silica C-18) The sensi tivity of the proposed method (detection limit for Al in serum = 5 mu g l(-1)) allowed aluminium speciation studies at clinically relevant c oncentrations (unspiked serum from dialysis patients). The results obt ained confirmed that transferrin is the only serum protein binding alu minium and it contains about 90% of total serum aluminium (post-elutio n 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.