Traceability in chemical measurements for the end users

Traceability is the foundation of any metrological science. Traditionally this term has been associated with the results of a particular measure as synonymous with the accuracy or reliability of such results (i.e., a certain level of quality). It ensures a clear( unbroken) relationship between results and the corresponding samples by using appropriate standards and calibrated equipment, This simple principle can be easily implemented in physical measurements, in which - commonly - the measurement process is mainly performed by the simple use of a (single) calibrated equipment. The case of chemical measurements is quite different because only the measurement step of the analytical process can be calibrated, but not the other steps, As measurements have a clear sample dependence, standards are not available in many situations. Therefore, the term metrology in chemistry needs to relate to a wider meaning of traceability, more addressed to a practical approach which is useful for end users (chemists and clients). Some adaptations are needed if a rational use of the term is to be applied to routine analytical work. In this article we propose a more practical and flexible view of term, 'traceability' in the field of metrology in chemistry. (C) 1999 Elsevier Science B.V. All rights reserved.