Methods for the determination of trace aluminium contamination in dialysis fluids

The problems associated with aluminium contamination of dialysis fluids are reviewed. The major sources of such contamination are generally the water supply or salts used in the manufacture of the fluids. It is generally desirable to keep the aluminium concentration of the dialysate below 15 micrograms/l. This trace level of aluminium results in problems of analysis. Literature methods, notably atomic absorption spectroscopy with electrothermal atomization, neutron activation analysis and inductively coupled plasma atomic emission spectroscopy are considered. Results from these methods are not always in agreement. It is concluded that graphite furnace atomic absorption spectroscopy (GF-AAS) is the most suitable technique. However, it is necessary to consider the effect of matrix interferences, notably chloride, on the determination of aluminium in dialysis fluids by this method. Reliable results for trace aluminium determinations by GF-AAS can be obtained using a suitable furnace programme together with matrix adjusters such as nitric or orthophosphoric acids.