Harmonisation protocols

The protocols of analytical methods and bioassays include the sampling and preparation steps of the test matrix before the test procedures. The sampling should be conducted in accordance with ISO 5667-16. There are already available harmonised protocols according to Hansen et al. [49]. The statistics of the ecotoxicity data should be conducted in accordance with ISO/CD 20281. 

The ability to provide accurate and reliable data is central to the role of analytical chemists, not only in areas like the development and manufacture of drugs, food control or drinking water analysis, but also in the field of environmental chemistry, where there is an increasing need for certified laboratories (ISO 9000 standards). The quality of analytical data is a key factor in successfully identifying and monitoring contamination of environmental compartments. In this context, a large collection of methods applied to the routine analysis of prime environmental pollutants has been developed and validated, and adapted in nationally or internationally harmonised protocols (DIN, EPA). Information on method performance generally provides data on specificity, accuracy, precision (repeatability and reproducibility), limit of detection, sensitivity, applicability and practicability, as appropriate. 

ISO/IUPAC/AOAC International Harmonised Protocol For Proficiency Testing of (Chemical) Analytical Laboratories... 

Precision is defined as the closeness of agreement between independent test results obtained under prescribed conditions.19 In a standard method the precision characteristics are obtained from a properly organised collaborative trial, i.e. a trial conforming to the requirements of an International Standard (the AOAC/ISO/IUPAC Harmonised Protocol or the ISO 5725 Standard). Because of the importance of collaborative trials, and the resource that is now being devoted to the assessment of precision characteristics of analytical methods before their acceptance, they are described in detail below. 

For example, at the highest level, conformance to the user requirements specification may be verified through data generated in house, through limited laboratory trials or through use of the full lUPAC harmonised protocol. What is critical here is the confirmation of the original user requirements under appropriate performance conditions (Figure 2). 

Recommended procedures for comparing methods and for taking a single method through to a full lUPAC collaborative trial with the harmonised protocol are covered in Chapter 9. Chapter 10 is a bibliography of recommended books and papers that should be consulted for more details in specific areas. 

The literature contains examples of collaborative trials that only prove that the method was not fit for its intended purpose The full lUPAC harmonised protocol is by its very nature an extensive and expensive exercise. From an economic perspective such trials should only be undertaken when there is good and well-documented evidence that it is likely that the method under evaluation is sufficiently robust. Investment of time and intellectual effort in method selection and the other aspects of the user requirements specification will pay great dividends. Prevention is better and nearly always cheaper than cure. 

The International Standardising Organisations, AOAC, ISO and IUPAC, have co-operated to produce an agreed International Harmonised Protocol For... 

Recently there has been progress towards a universal acceptance of collaboratively tested methods and collaborative trial results and methods, no matter by whom these trials are organised. This has been aided by the publication of the IUPAC/ISO/AOAC Harmonisation Protocol on Collaborative Studies.14 That Protocol was developed under the auspices of the International Union of Pure and Applied Chemists (IUPAC) aided by representatives from the major organisations interested in conducting collaborative studies. In particular, from the food sector, the AO AC International, the International Organisation for Standardisation (ISO), the International Dairy Federation (IDF), the Collaborative International Analytical Council for Pesticides (CIPAC), the Nordic Analytical Committee (NMKL), the Codex Committee on Methods of... 

INTERNATIONAL UNION OF PURE AND APPLIED CHEMISTRY, The International Harmonised Protocol for the Proficiency Testing of (Chemical) Analytical Laboratories, ed. Thompson M and Wood R, Pure Appl. Chem., 1993 65 2123-2144 (also published in J. AOAC International, 1993 76 926-940). 

Thompson M and Wood R, 1993, The International harmonised protocol for the proficiency testing of (chemical) analytical laboratories. Pure and Applied Chem. 65,2123-2144. 

It is a study, which focuses on the performance of the laboratory and of the analyst. Several examples of such studies are described in literature [42,43]. It helps participants to compare their performance and their method to the performance of other laboratories and/or to an assigned value [44,45]. Repetitive laboratory performance studies to evaluate if laboratories are able to fulfil a given task are often called proficiency testing schemes. First guidelines have been set under the ISO Guide 43 [46]. In 1993, lUPAC has published an international harmonised protocol for the proficiency testing of (chemical) analytical laboratories [3] which sets the basic criteria for the organisation of laboratory performance studies. 

To have a real impact on the quality of the laboratory performance the participation in interlaboratory performance studies should be done on a regular basis and should be an integral part of the laboratory quality assurance and quality control system. The common project of lUPAC/AOAC/ISO, leading to a harmonised protocol [3] gives several indications and recommendations on the organisation and evaluation of such interlaboratory studies. 

In order to bring clarity and confidence in the evaluation of such studies the lUPAC harmonised protocol [3] recommends one evaluation method the so-called z-score. This evaluation is based on the comparison of the obtained results x, to an assigned value Tof a laboratory, which should be the best estimate of the true value. The r-score is expressed as ... 

Another scoring system also mentioned in the harmonised protocol but not recommended by the authors is the Q scoring system largely used in occupational hygiene monitoring ... 

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