title: A drift correction procedure.
abstract: A procedure is introduced that can mitigate the deleterious effect of low-frequency noise [Formula: see text] often termed drift [Formula: see text] on the precision of an analytical experiment. This procedure offers several performance benefits over traditional designs based on the periodic measurement of standards to diagnose and correct for variation in instrument response. Using repeated measurements of every sample as a drift diagnostic, as opposed to requiring the periodic measurement of any given sample or standard, the analyst can better budget the measurement time to be devoted to each sample, distributing it to optimize the uncertainty of the analytical result. The drift is diagnosed from the repeated measurements, a model of the instrument response drift is constructed, and the data are corrected to a "drift-free" condition. This drift-free condition allows data to be accumulated over long periods of time with little or no loss in precision due to drift. More than 10-fold precision enhancements of analytical atomic emission results have been observed, with no statistically significant effects on the means. The procedure is described, performance data are presented, and matters regarding the procedure are discussed.
authors.affiliation: Chemical Science and Technology Laboratory, Analytical Chemistry Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8391.
authors.forename: M L
authors.initials: ML
authors.lastname: Salit
authors.forename: G C
authors.initials: GC
authors.lastname: Turk