Analytical quality assurance

The importance of the analytical control depends on the preparation tolerance of the mixture method applied. In case of preparation methods with higher inaccuracies it is common practice to determine the mole fraction by means of analysis. Even if the mixture is gravimetrically produced, analytical control cannot be renounced. On the one hand, it can never be excluded, for instance, that systematic weighing errors or individual errors of the operator occur. On the other hand, above all in case of corrosive components, adsorption effects and reactions with the inner surface of the gas cylinder cannot be excluded. Such effects can only be detected analytically. 

The common analytical methods shall only be listed concisely  

Wet-chemical absolute methods Electrochemical methods Optical methods (FTIR, IR, UV-VIS) 

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A second reason for using reference materials in clinical chemistry is to ensure values obtained are traceable to those in a recognized, authoritative reference material (Johnson et al. 1996). As a result, the assignment of values of secondary and tertiary reference materials, calibrants, controls, and proficiency samples shordd be performed as precisely as possible (Johnson et al. 1996). Surprisingly there is still debate on this topic, and on the need for clinical chemistry to incorporate the principals of analytical quality assurance (Dybkaer et al. 1999). 

Mesliy RJ et al. 1991) Analytical Quality Assurance - A Review. Analyst 116 975-990. 

Parr RM, Fajgelj A, Dekner R, Vera Ruiz H, Carvalho FP, and Povinec PP (1998) IAEA analytical quality assurance programs to meet the present and future needs of developing countries. Fresenius J Anal Chem 360 287-290. 

Standards are being used in the context of Analytical Quality Assurance, which is the demonstration to the end-user that the delivered product, the measurement data, are reliable and have been made according to the best practices currently possible. Standards facilitate, some would say are essential to, living and trading in the global village. Standards have become standard in everyday life. 

A Protocol for Analytical Quality Assurance in Public Analyst s Laboratories, Association of Public Analysts, Sheffield (1986). 

Danzer K (1993) Information content of an analytical result and its assessment by interlaboratory studies. IDF Special Issue 9302 Analytical quality assurance and good laboratory practice in dairy laboratories. IDF, Brussels... 

The Food Standards Agency undertakes food chemical surveillance exercises. It has developed information for potential contractors on the analytical quality assurance requirements for food chemical surveillance exercises. These requirements are describe below but reproduced as an appendix to this chapter, they emphasise the need for a laboratory to produce and report data of appropriate quality. The requirements are divided into three parts dealing with ... 

Appendix Information for potential contractors on the analytical quality assurance requirements for food chemical surveillance exercises... 

Part A describes the information that is to be provided by potential contractors at the time that the ROAME Bs are completed for submission to the Group. Provision of this information will permit any FSA Analytical Group and customers to make an informed assessment and comparison of the analytical quality of the results that will be obtained from the potential contractors bidding for the project. Previously potential contractors have not been given defined guidance on the analytical quality assurance information required of them and this has made comparison between potential contractors difficult. Part A is supplied to potential contractors at the same time as further information about the project is supplied. 

Approaches for Evaluating Acceptable Methods of Analysis Method Performance Characteristics and Criteria Approach Analytical Quality Assurance... 

Analytical method validation forms the first level of QA in the laboratory. Analytical quality assurance (AQA) is the complete set of measures a laboratory must undertake to ensure that it is able to achieve high-quality data continuously. Besides the use of validation and/or standardized methods, these measures are effective IQC procedures (use of reference materials, control charts, etc.), with participation in proficiency testing schemes and accreditation to an international standard, normally ISO/IEC 17025 [4]. Method validation and the different aspects of QA form the subject of Section 8.2.3. 

This update on analytical quahty issues a common understanding on the topics of method validation, traceabihty, and MU of measurements. The interrelationships between method validation and traceability and MU of results have been elucidated. Throughout the landscape of guidelines and standards, the most relevant information was selected, compiled, and summarized. Different approaches are discussed for establishing traceability and assessing MU of analytical methods in general. The importance of both concepts and the link with method validation and analytical quality assurance are highlighted. 

There has been a huge amount of analytical work on metals such as lead in food. Indeed a large part of the periodic table has been covered. Early work on metals identified that analytical quality assurance is a key tool in the surveillance of food for chemical contaminants. It also led to the development of toxicological standards which can be used to define whether or not surveillance results show there is a hazard to consumer health. Both of these types of approaches are now standard in the best surveillance programmes, whether they are on contaminants or additives in food. 

Twenty-eight of fifty-four samples purchased were found to have coatings made from polyester resins and so their contents were analysed for TPA and IPA. Analysis was by GC-MS after extraction and derivatisation to form the dimethyl esters of TPA and IPA. Included in the analytical quality assurance steps taken was participation in a check-sample exercise whereby four samples were supplied by a second laboratory and analysed blind. The performance of the testing laboratory was assessed from the accuracy and precision of their measurements and was demonstrated to be acceptable. 

Presented at CITAC International Symposium on Analytical Quality Assurance for the 21st Century, Sydney, Australia, 15-16 October 1998... 

Millar RG (2001) NARL Analytical Quality Assurance Study No. 01-04, Australian Govt. Analytical Laboratories, Cottesloe, Western Australia Thompson M, Lowthian PJ (1995) Analyst 120 271 272... 

Even today, in an age where analytical quality assurance procedures and accreditation are part of most laboratories daily routines, an often-neglected section in a published paper is where you describe the quality control procedures you have used during the analytical work. It is only natural that the author points out what he/she thinks has been done well. It is equally natural that the weak spots have been suppressed or otherwise disregarded. What procedures the author will describe are thus rather subjective. 

It is generally recognized and accepted that analytical methods must be suitable for the intended use. Furthermore, EU Directives 85/591/EEC, 89/397/EEC and 93/99/ EEC state that analytical procedures for compliance testing with food laws are to be carried out on the basis of validated methods. Method validation is known as the process used to confirm that a procedure is fit for a particular analytical purpose. This process, an essential part of analytical quality assurance, can be described as the set of tests used to establish and document performance characteristics of a method. The performance characteristics of a method are experimentally derived values for the fundamental parameters of importance in assessing the suitability of the method (Horwitz 1988, 1995 Thompson and Wood 1993, 1995 Eurachem 1996 FAO 1998 US EPA 1995 US FDA 1993a). These parameters include ... 

Analytical Quality Assurance and Quality Control Procedures 73... 

ANALYTICAL QUALITY ASSURANCE AND QUALITY CONTROL PROCEDURES... 

J. Engman, L. Jorhem, Toxic and essential elements in fish from Nordic waters, with the results seen from the perspective of analytical quality assurance, Food Addit. Contam., 15 (1998), 884-892. 

American Chemical Society publications Analytical Chemistry, Environmental Science and Technology, and the Journal of the American Chemical Society. These descriptions are usually brief and often just summarize the techniques and procedures of the method. Research reported in scientific journals is often focused on a detailed investigation of a narrow subject area, and new analytical techniques and procedures developed for the research are rarely tested in a broader context. Analytical quality assurance and control are often minimal or not described. Techniques and procedures described in scientific research journals are the beginnings of analytical methods, however, they usually require considerable development, modifications, and testing before they become widely accepted analytical methods. 

The Marine Environmental Laboratory of IAEA located in Monaco is involved in the measurement and understanding of marine radioactivity. Analytical quality assurance, the use of isotopes as tracers and site-specific radiological assessments are central... 

Figure 19-11 Operating specifications chart for an analytical quality requirement of 10% (T o) and 90% analytical quality assurance for systematic error. Allowable inaccuracy is plotted on the y-axis versus allowable imprecision on the x-axis.

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