selective micro-sample

in spectrochemical analysis
Also contains definition of: individual particle analysis
A sample which results where a small portion has been separated from the lot or laboratory sample by selective means such as magnetic-, density-, or manual separation, by micro-drilling, or by centrifugation, e.g. the separation of magnetic materials from a geological material, or the separation of metal particles from a lubricating oil. If individual particles are analysed the term individual particle analysis is applied.
PAC, 1988, 60, 1461. 'Nomenclature, symbols, units and their usage in spectrochemical analysis-X. Preparation of materials for analytical atomic spectroscopy and other related techniques (Recommendations 1988)' on page 1467 (