NOMENCLATURE FOR SAMPLING IN ANALYTICAL-CHEMISTRY - (RECOMMENDATIONS 1990)

The IUPAC definition of the term SAMPLE appearing in the “Compendium of Analytical Nomenclature, Definitive Rules 1987” is, “the actual material investigated, whether diluted or undiluted.” Although many colloquial analytical chemical communications use this definition, it frequently results in confusing, ambiguous, and contradictory usages. The term has been used in at least 17 ways in IUPAC documents and other scientific literature. Such ubiquitous applications often do not permit analysts to orient themselves as to where they are in the sampling and analytical scheme. A remedy is proposed, based upon the vocabulary of the International Organization for Standardization (ISO), that requires: (1) Confine the use of the term SAMPLE to its statistical concept: If a potential exists for a sampling error due to the heterogeneity of a population, the term SAMPLE with an appropriate modifier to indicate its position in the sampling scheme should be used (i.e., increment, primary sample, secondary sample, etc., laboratory sample, test sample, test portion). (2) Once analytical work begins by measuring the test portion, avoid the term SAMPLE; use TEST or UNKNOWN as the modifier as in TEST SOLUTION, TEST EXTRACT. For the common step usually designated as PREPARATION OF SAMPLE in methods of analysis, use more specific terms, such as PURIFICATION, SEPARATION, or ISOLATION [of analytes]. (3) Use the term SPECIMEN for a sample from a parent population that changes with time, as in living organisms, circulating blood, or a flowing river. In this case the phenomenon under study and the sampling error are confounded in such a way that they can not be separated. © 1990 De Gruyter