LINEAR SCAN STRIPPING VOLTAMMETRY AT GLASSY-CARBON BASED THIN MERCURYFILM ELECTRODES FOR DETERMINATION OF TRACE ALUMINUM IN DIALYSIS FLUIDS

Linear scan cathodic stripping voltammetry at glassy-carbon based thin mercury film electrodes is a simple and inexpensive alternative for d etermining trace AI(III) in dialysis fluids. The efficiency of a varie ty of ligands (SVRS, Cupferron and Blue Black Eriochrome R) was evalua ted comparing their voltamperometric response by application of a line ar scan mode, after preconcentration into the mercury film electrode a s Al(III) complexes. The best results were obtained when Cupferron was used as ligand, since its stripping current compares favourably in te rms of sensitivity and resolution. The sharply defined cathodic peak a t -1.3 V, corresponding to the reduction of the interfacial accumulate d complex, could be used for quantitation. The response is linear up t o 50 mu g/l; correlation coefficient, 0.995. The relative standard dev iation (at 20 mu g/l level) is 3.5% a detection limit of 0.5 mu g/l wa s estimated from the signal to noise characteristics of the response f or 5 mu g/l, which compares favourably among the reported electroanaly tical methods for aluminium. We calibrated the method under conditions of use estimating the trace: aluminium exposure in patients undergoin g dialytic treatment.