The expansion of interest in environmental pollution has directed considerable effort towards obtaining lower limits of detection for many toxic elements. Analysis for mercury in particular has placed considerable demands on currently available instrumentation and a recent review reflects the great analytical interest in this element. Both atomic-absorption and atomic-fluorescence techniques have been commonly employed to determine mercury and both have their advantages and disadvantage.
In our laboratory, we have for many years used an atomic-fluorescence technique. However, demands for lower limits of detection coupled with the increased volume of samples presented for analysis have rendered our apparatus inadequate for present requirements.
When deciding on a replacement, it was obvious from the number of samples analysed that one instrument would have to be dedicated to mercury analysis. Rather than use an atomicabsorption procedure it was decided, after a review of the literature, that a purpose-built non-dispersive fluorescence instrument could achieve the levels required.
Non-dispersive fluorescence has not gained the popularity of dispersive techniques. The increased light-gathering power of a non-dispersive system is often off set by background scatter from the atom cell, usually a flame. However, cold-vapour generation gives minimum background scatter and considerable advantages could be obtained by using cold-vapour generation with a non-dispersive fluorescence system. Non-dispersive mercury fluorescence has been reported in the literature, but in some instances the detection limits obtained required extreme conditions, eg., solar-blind photomultipliers or sodium-lit rooms.
This work describes the performance of a simple non-dispersive fluorescence spectrometer and its application to the routine analysis of marine samples.
Hutton, R.C. and Preston, B., 1980. A simple non-dispersive atomic-fluorescence spectrometer for mercury determination, using cold-vapour generation. Analyst, 105(1255), pp.981-984.
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