The principle of pooled calibrations and outlier retainment elucidates optimum performance of ion chromatography

Journal article

Authors / Editors

Andersen, Jens

Research Areas

No matching items found.

Publication Details

Author list: Andersen JET, Mikolajczak M, Wojtachnio-Zawada KO, Nicolajsen HV

Publisher: Elsevier

Place: AMSTERDAM

Publication year: 2012

Journal: Journal of Chromatography B (1570-0232)

Journal acronym: J CHROMATOGR B

Volume number: 908

Start page: 122

End page: 127

Number of pages: 6

ISSN: 1570-0232

Languages: English-Great Britain (EN-GB)

View in Web of Science | View on publisher site | View citing articles in Web of Science

Abstract

A principle with quality assurance of ion chromatography (IC) is presented. Since the majority of scientists and costumers are interested in the determination of the true amount of analyte in real samples, the focus of attention should be directed towards the concept of accuracy rather than focussing on precision. By exploiting the principle of pooled calibrations and retainment of all outliers it was possible to obtain full correspondence between calibration uncertainty and repetition uncertainty, which for the first time evidences statistical control in experiments with ion chromatography. Anions of bromide were analysed and the results were subjected to quality assurance (QA). It was found that the limit of quantification (LOQ) was significantly underestimated by up to a factor of 30 with respect to the determination of concentration of unknowns. The concept of lower-limit of analysis (LLA) and upper-limit of analysis (ULA) were found to provide more acceptable limits with respect to reliable analysis with a limited number of repetitions. An excellent correspondence was found between calibration uncertainty and repetition uncertainty. These findings comply with earlier investigations of method validations where it was found that the principle of pooled calibrations provides a more realistic picture of the analytical performance with the drawback, however, that generally higher levels of uncertainties should be accepted, as compared to contemporary literature values. The implications to the science analytical chemistry in general and to method validations in particular are discussed. (C) 2012 Elsevier BM. All rights reserved.

Keywords

Certified reference material, Internal standard, Ion chromatography, Quality assurance

Documents