ANALYTICAL MINIMALISM APPLIED TO THE DETERMINATION OF TRACE-ELEMENTS BY ATOMIC SPECTROMETRY

In analytical minimalism, each stage of the analysis is evaluated to minimize the time, cost, sample requirement, reagent consumption, energy requirements and production of waste products. These parameters are often inter-related. If the objective of digestion of biological tissues, foodstuffs and environmental samples is taken as the complete dissolution of the trace elements, then the time of digestion by conventional heating can be reduced considerably to times comparable with pressure digestion using microwave heating. The development of rapid and simple partial digestion techniques is reviewed. In electrothermal atomic absorption spectrometry, by assessing the function and time of each stage in the programme; it has been possible to reduce the programme time to about 30 s for a number of determinations. Recent developments in fast furnace technology are reviewed, particularly on omission of the ashing stage and drying with hot injection or high temperatures. With reduction in furnace programme time, the time taken by the autosampler (30-35 s) becomes dominant. Developments to reduce this time by 10-20 s are discussed. In the evaluation of results, minimal time and effort by the analyst is ensured by customized computer programmes. The programmes, variants of one or two basic programmes, are adapted for each determination to retain the value of standards, to correct for blanks and to allow conversion from gl(-1) to mol l(-1).