Atomic absorption spectrometric determination using a multipurpose dialyser in a flow injection system

Abstract

A multipurpose dialyser unit was designed and incorporated into the conduits of flow injection (FI) systems and employed for automated dilution and multi-component determinations before detection by atomic absorption spectrometry (AAS). The combined multipurpose dialyser–FI-AAS systems were applied to the determination of copper(II) in industrial effluent samples where there is a great variation in copper(II) concentration levels. Both proposed multipurpose dialyser–FI-AAS systems were suitable to handle the wide variety in concentration levels present in industrial effluent samples. The automated dialyser–dilution system seemed to be ideally suited for the determination of a single element in industrial effluents where the concentration of the element varied considerably in the samples. The advances of the method were further enhanced with the removal of solid particles present in industrial effluents. These particles were of such a nature that they continuously blocked the inlet path to the nebulizer of the AAS detector. The multi-component determination–dialyser system seemed to be ideally suited for the simultaneous determination of elements, which is an advantage for big routine laboratories where there is a pressure on the number of samples and elements to be analysed. The scaling down of sample handling to a sample channelled to various streams and detectors is a further advantage. A prerequisite of the multi-component determination dialyser–FI-AAS system is, however, the number of atomic absorption spectrophotometers required and this may be a disadvantage of this system. The results obtained for copper(II) for both systems at a sampling rate of 120 samples per hour compared favourably with the standard manual atomic absorption spectrometric method. With 75 µl dialysates injected, the relative standard deviation of the draining point with the smallest membrane area was better than 0.3%.