Book Description

For many years in the field of chemical analysis, the concepts of and scientific foundation for the detection limit (DL) and the quantification limit (QL) were in the eyes of the beholder: that is, there was no established consensus on how to compute DL and QL for a given analytical method. Then, in 1968 (and reiterated in 1999), Lloyd Currie of the National Bureau of Standards, later renamed the National Institute of Standards and Technology, published what has become the internationally accepted scientific basis for both concepts. Currie uses statistical hypothesis theory to determine the DL, the methods critical value, and the QL of a completely specified measurement system in analytical chemistry. Curries methodology has been adopted internationally by the International Union of Pure and Applied Chemistry (IUPAC) and by the International Organization for Standardization (ISO), among other international consensus standards bodies. ASTM International, however, has not yet developed a unified DL standard for the general measurement community. ASTM Committee D22 on Air Quality recently developed a draft standard practice for DL in air-quality measurements, which is based on the Currie method. Once finalized, this standard should ensure that DL computations for air measurements using ASTM standards are consistent with those made worldwide using the IUPAC and ISO standard DL methods.