Linear Scan Stripping Voltammetry at Glassy-Carbon Based Thin Mercury Film Electrodes for Determination of Trace Aluminium in Dialysis Fluids

Linear scan cathodic stripping voltammetry at glassy-carbon based thin mercury film electrodes is a simple and inexpensive alternative for determining trace Al(III) in dialysis fluids. The efficiency of a variety of ligands (SVRS, Cupferron and Blue Black Eriochrome R) was evaluated comparing their voltamperometric response by application of a linear scan mode, after preconcentration into the mercury film electrode as Al(III) complexes. The best results were obtained when Cupferron was used as ligand, since its stripping current compares favourably in terms of sensitivity and resolution. The sharply defined cathodic peak at -1.3 V, corresponding to the reduction of the interfacial accumulated complex, could be used for quantitation. The response is linear up to 50 μg/l; correlation coefficient, 0.995. The relative standard deviation (at 20 μg/l level) is 3.5%, a detection limit of 0.5μg/l was estimated from the signal to noise characteristics of the response for 5 μg/l, which compares favourably among the reported electroanalytical methods for aluminium. We calibrated the method under conditions of use estimating the trace aluminium exposure in patients undergoing dialytic treatment.