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Trends in Analytical Chemistry, Vol. 23, No. 8, 2004

Trends

Trends in quality in the analytical laboratory. II. Analytical method validation and quality assurance
Isabel Taverniers , Marc De Loose, Erik Van Bockstaele 1
It is internationally recognized that validation is necessary in analytical laboratories. The use of validated methods is important for an analytical laboratory to showits qualification and competency. In this update on analytical quality, we place validation of analytical methodologies in the broader context of quality assurance (QA). We discuss different approaches to validation, giving attention to the different characteristics of method performance. We deal with the concepts of single-laboratory or in-house validation, inter-laboratory or collaborative study,standardization, internal quality control (IQC), proficiency testing (PT), accreditation and, finally, analytical QA (AQA). This article provides a good, complete, up-to-date collation of relevant information in the fields of analytical method validation and QA. It describes the different aspects of method validation in the framework of QA. It offers insight and direct help to anyone involved in anyanalytical methodologies, whether they are an academic researcher or in the industrial sector. ª 2004 Elsevier Ltd. All rights reserved.
Keywords: Accreditation; Analytical method validation; Performance parameter; Quality assurance; Quality control Applied Chemistry; k, Numerical factor used in formulae for LOD and LOQ; LIMS, Laboratory information management system; LOD, Limit of detection; LOQ,Limit of quantification; MRL, Maximum residue level ( ¼ PL); MRPL, Minimum required performance limit; MU, Measurement uncertainty; PL, Permitted limit ( ¼ MRL); PT, PTS, Proficiency Testing (Scheme); q, Quantity of measurand; QA, Quality assurance; QC, Quality control; r, Repeatability value or limit; R, Reproducibility value or limit; RM, Reference material; RSD, Relative standard deviation; SD(s), Standard deviation(s); SOP, Standard operating procedure; USP, United States Pharmacopeia; WHO, World Health Organization; x, Measured response or signal

1. The role of method validation in AQA The terms validation and quality assurance (QA) are widely used. However, a lot of analysts and laboratories do not know the exact meaning neither the difference nor the relationship between the twoterms. Validating a method is investigating whether the analytical purpose of the method is achieved, which is obtaining analytical results with an acceptable uncertainty level [1]. Analytical method validation forms the first level of QA in the laboratory (Fig. 1). AQA is the complete set of measures a laboratory must undertake to ensure that it can always achieve high-quality data. Besides theuse of validation and/or standardized methods, these measures are: effective IQC procedures (use of reference materials (RMs), control charts, etc.); participation in PT schemes; and, accreditation to an international standard, normally ISO/IEC 17025 [1–3]. 535

Isabel Taverniers*, Marc De Loose, Erik Van Bockstaele Department for Plant Genetics and Breeding (DvP), Centre for Agricultural Research(CLO), Ministry of the Flemish Community, Caritasstraat 21, B-9090 Melle, Belgium

*Corresponding author: Tel.: +32-9-272-2876; Fax: +32-9-272-2901; E-mail: i.taverniers@clo.fgov.be 1 Department for Plant Production, Ghent University, Coupure Links 653, B-9000 Gent, Belgium.

Abbreviations: AOAC, Association of Official Analytical Chemists; AQA, Analytical quality assurance; ASTM, AmericanSociety for Testing and Material; c, Concentration of measurand; CCMAS, Codex Committee on Methods of Analysis and Sampling; CCa , Decision limit; CCb , Detection capability; CEN, European Committee for Normalization; CITAC, Cooperation on International Traceability in Analytical Chemistry; CRM, Certified reference material; CV, Coefficient of variation ( ¼ % RSD); EA, European Cooperation for...