Critical study of the speciation of aluminum in biological fluids by size-exclusion chromatography and electrothermal atomic absorption spectrometry

Pooled serum and the serum of a healthy volunteer were spiked with aluminum and aluminum species were separated on Bio-gel columns. With the P10 column, less than 40% of the aluminum was eluted with the high-molecular-weight (m.w.>20 00) fraction; the total aluminum concentration was 600 μg l^?1. Tw lower m.w. fractions were also recovered. With the P4 column, only one high m.w. (65–100%) and one low m.w. (0–53%) fraction were recovered; the total Al concentrations was 10–110 μg l^?1. When a hemofiltrate obtained from uremic patients on regular hemofiltration and spiked with 60–110 μg Al l^?1 was applied to the P4 gel, two lower m.w. fractions were detected. The adsorption/desorption of “free” aluminum on the column was studied with 0.9% NaCl solution, Earle's medium and filtrate. Normal column fractionation and frontal analysis (adsorption and desorption breakthrough curves) were used. Redistribution of aluminum seemed not to occur within the serum when in contact with the column, but contamination from extraneous aluminum could greatly alter the aluminum distribution. Different sources of errors were identified.8