REFERENCE MATERIALS FOR SMALL-SAMPLE ANALYSIS

Many modem analytical techniques use small solid samples and lack prop er reference materials for their calibration and quality assurance. A remedy to this deficiency may be in the development of a new genre of highly homogeneous natural matrix materials, their properties being st udied with analytical techniques such as PIXE and CL-PIXE, solid sampl ing AAS, scanning electron microscopy in combination with electron pro be X-ray microanalysis, and INAA. Suitable natural materials may be ob tained in form of single cell biological materials, finely dispersed s uspensions and precipitates such as air particulate matter or sediment s, and by appropriate particle size reduction of complex matrices. Ini tial studies have been carried out on single cell green algae biomass and air particulate matter, as well as several processed materials. Na rrow particle size distributions with particles preferably below 10 mu m diameter may assure the desired analytical homogeneity. The determi nation of sampling parameters for individual measurands will ascertain the utility of a material for small-sample analysis.