The handbook of analytical methods for trace elements as adopted by the national reference laboratories for residues

The instrumental approaches, quality assurance schemes and management of chemical laboratories should in general be harmonized at the highest possible level. This is all the more so for the national reference laboratories (NRLs) for residues in live animals and their products which have to implement quality assurance systems inspired to the principles of good laboratory practice as well as to the general norms for the operation of testing laboratories (EN 45000 criteria). Directive 23/96/EC of 29 April 1996 prescribes that NRLs are assisted in this process by the four community reference laboratories (CRLs) for residues. To this end, the Rome CRL systematically collects in a handbook all the analytical methods in use at NRLs for the determination of As, Cd, Cu, Hg and Pb, as well as other chemical elements, in animal matrices. One major goal of this action is to foster the harmonization of analytical approaches by the NRLs and their ability to provide comparable results of similar quality. The Rome CRL is committed to revise this handbook twice a year. The role of the handbook is also to encourage the exchange of information among the NRLs as regards the possibility of improving existing methods.     

The current state of analytical control in Lithuania

In Lithuania research and development in chemical analysis are concentrated in scientific institutes and universities. The main fields of interest focus on biosensors, electrochemical sensors, sampling techniques and methods, study of atomization processes in spectrochemical analysis and noise evaluation in analytical measurements. Some laboratories also take part in international environmental monitoring programmes. There are about 50 researchers at the Ph.D. level engaged in analytical chemistry and several hundred technicians specialized in the field of analytical control. About one hundred chemical laboratories are active in scientific institutes, universities and factories. Specialized laboratories of chemical analysis are at the disposal of Environmental Control and Health Protection Departments and forensic investigation organizations. So far no laboratories are accredited according to the ISO 9000 norms. Special courses on analytical chemistry are offered at a few schools of higher education in the country. Only at the Department of Analytical Chemistry of the University of Vilnius specialized programmes are available to postgraduate students working towards a Ph.D. to improve their skills in current techniques of analytical chemistry. Recently the Technical Committee TC-16 for Chemical Analysis was formed within the standardization system of Lithuania. Its main activities are centered on issues such as national terminology, certified reference materials (CRMs), analytical methods and analytical quality assurance. There are numerous problems related to national terminology, the preparation of special documents in the field of analytical control and the production of regional environmental CRMs. Problems, also arise in obtaining and using CRMs for analytical instrument calibration and validation.     

Different approaches to legal requirements on validation of test methods for official control of foodstuffs and of veterinary drug residues and element contaminants in the EC

 In order to ensure food consumer protection as well as to avoid barriers to trade and unnecessary duplications of laboratory tests and to gain mutual recognition of results of analyses, the quality of laboratories and test results has to be guaranteed. For this purpose, the EC Council and the Commission have introducedprovisions – on measures for quality assurance for official laboratories concerning the analyses of foodstuffs on the one hand and animals and fresh meat on the other, – on the validation of test methods to obtain results of sufficient accuracy. This article deals with legal requirements in the European Union on basic principles of laboratory quality assurance for official notification to the EC Commission and on method validation concerning official laboratories. Widespread discussions and activities on measurement uncertainty are in progress, and the European validation standards for official purposes may serve as a basis for world-wide efforts on quality harmonization of analytical results. Although much time has already been spent, definitions and requirements have to be revised and further additions have to be made.     

From misconception to a must: The measured merits of total quality management and accreditation in INAA

Increasingly govemmental bodies and industry require that supporting analytical laboratories have their quality assurance program implemented in a quality system by international standards such as derived from the ISO-25 guide. Neutron activation analysis (NAA) laboratories may have to deal with this trend too. In universities and research laboratories the need for it, and the implications of total quality management system are sometimes misconceived by unfamiliarity with the issue. The laboratory for INAA in Delft has been accredited for its quality system since 1993. Some of the tangible improvements since the introduction of quality management are presented. Four strategical considerations are given to consider the introduction of quality management at NAA laboratories, viz. with respect to the role of NAA for the validation of other methods, the role of NAA in the certification of reference materials, the preservation of knowledge and the acceptance of NAA as a respectable method.     

Quality assurance in the view of a commercial analytical laboratory

 The necessity for analytical quality assurance is primarily a feature of the analytical process itself. With the full establishment of the EU domestic market, it is also becoming a legal necessity for an increasing number of analytical laboratories. The requirements which laboratories will need to fulfil are stipulated in DIN EN 45 001. Accredited testing laboratories must in fact provide evidence that they work solely in accordance with this standard. National and EU commissions, which are legislative authorities, tend therefore to specify analytical methods, e.g. in the form of regulations or appendices thereto, intended to ensure that results from different laboratories will be comparable and hence will stand up in a court of law. The analytical quality assurance system (AQS), introduced by the Baden-Württemberg Ministry for the Environment in 1984, obliges laboratories to regularly participate in collaborative studies and thereby demonstrate their ability to provide suitably accurate analyses. This alone, however, does not sufficiently demonstrate the competence of a laboratory. Only personal appraisal of the laboratory by an auditor, together with the successful analysis of a sample provided by the same and performed under his observation, can provide proof of the competence of the laboratory. From an analytical point of view, the competence of a laboratory must be regarded as the decisive factor. Competence can only be attained through analytical quality assurance, which thus must be demanded of all laboratories. Received: 4 October 1996 Accepted: 15 January 1997     

Current methods of analysis for the determination of trichothecene mycotoxins in food

This article describes the trends in analytical techniques for the determination of trichothecene mycotoxins, namely deoxynivalenol, and T-2 and HT-2 toxins in cereals and cereal products with particular emphasis on screening and rapid approaches. The driving force behind the changing methodologies is mainly attributed to legislative demands. However, for commercial and governmental testing laboratories, the need to use validated official methods is ever increasing to ensure quality assurance of results.Much research has been undertaken to improve screening assays, highlighted by the number of new methods using a variety of formats and platforms, including optical and electrochemical biosensors. Significant advances in the traditional reference methods have also been demonstrated in addition to the emergence of a variety of commercial immunoaffinity and solid-phase extraction columns for clean up. The use of liquid chromatography coupled to tandem mass spectrometry for mycotoxin detection is ever increasing, allowing simultaneous determination of many toxins in various sample matrices.     

An overview of reference materials prepared for standardization of DNA typing procedures

Although DNA typing is an accurate, precise, and robust procedure, quality assurance is enhanced by availability of a suitable reference material. The National Institute of Standards and Technology (NIST) recently released a Standard Reference Material (SRM) that meets the calibration and quality assurance needs of laboratories that perform DNA typing. Each step of the analytical process of DNA typing may be verified by one or more of twenty different components of the SRM. As newer, more sensitive methods for DNA typing have been introduced into the human identification laboratory repertoire, new SRMs will be required for quality assurance. A second SRM for PCR-based tests is under development and soon to be available, is also described.     

Quality assurance systems in research and routine analytical laboratories

In our article we explain the connections between the implementation of quality assurance (QA) in research and routine analytical laboratories. J. K. Taylor claims that QA in an analytical laboratory consists of two independent but closely related terms, quality control and quality assessment. If we construct the QA system according to his ideas, problems concerning quality can be solved with only one concept regardless of the type of analytical laboratory. Therefore there is no need to introduce new QA standards for research laboratories as suggested in some papers. In the routine laboratory quality control is more important, while in the research laboratory quality assessment is dominant.     

Improvement, quality assurance and analytical results on the river Elbe contamination in the Czech Republic

Environmental analysis at trace levels is a new field of research in the Czech Republic since about ten years. New methods have to be adapted, pollution sources have to be investigated and quality assurance has to be established. The improvement in the detemination of trace substances in the Elbe river, mainly that of organic pollutants, is shown. A first insight on an international level is given into the origin of pollution in the Czech part of the Elbe river and the analytical work provided by the Czech water research institute and one of the most important monitoring laboratories.     

Quality assurance systems in research and routine analytical laboratories

 In our article we explain the connections between the implementation of quality assurance (QA) in research and routine analytical laboratories. J. K. Taylor claims that QA in an analytical laboratory consists of two independent but closely related terms, quality control and quality assessment. If we construct the QA system according to his ideas, problems concerning quality can be solved with only one concept regardless of the type of analytical laboratory. Therefore there is no need to introduce new QA standards for research laboratories as suggested in some papers. In the routine laboratory quality control is more important, while in the research laboratory quality assessment is dominant.

     

新工科背景下分析化学中质量保证和质量控制的教学改革探究*

通过对目前分析化学教学中存在问题的分析,探究了新工科背景下分析化学专业中关于质量保证和质量控制方面的教学改革,提出了增设“分析化学中的质量保证和质量控制”或者类似的课程的建议,指出分析化学的教学应该围绕整个分析过程展开,并将分析化学中的质量保证和质量控制知识融入分析全过程中,注重理论课程与实践课程相互结合的同时更加强调应用性,增强学生的实践能力和分析问题、解决问题的能力。此外,分析化学教学重在“分析”,要与分析实验室/检测机构保持紧密联系,应建立以市场为导向、以技术为核心的教学活动,从而实现为社会不断培养与时俱进的分析人才的教育目标。     

统计质量保证技术在分析测试实验室内部质量控制中的应用

对通过统计质量保证（SQA）技术进行分析测试实验室内部质量控制（IQC）的方法作了初探。研究结果表明,SQA技术的应用能保证实验室始终处于统计受控状态,确保测试数据的有效性,有利于分析测试实验室质量保证活动的开展。     

Production and certification of “fresh” reference material for macronutrient analysis

Summary Reference materials for carrying out in-house quality assurance by food laboratories that analyse macronutrients have to date been inadequate. The freeze-dried, very specialized, materials that exist on the market are not always comparable with ordinary food products analysed at those laboratories.A homogeneous, fresh, canned meat material was produced by an ordinary cannery. The total amount of material (pork, nitrite salt and water) was 1700 kg. During production, the fat content was continuously analysed in the different sub-batches and combinations are made accordingly. The material was packed in tin cans containing 200 g, and tested for homogeneity. The shelf life is, by experience, at least five years. A large number of authorized public and industry laboratories participated in the certification procedure. For each constituent different types of standard analytical methods were used. The material is offered for sale together with a certificate, giving mean values for moisture, ash, fat, nitrogen, sodium, sodium chloride and hydroxyproline content. The uncertainty is given as standard deviations including the analytical error and the variations between laboratories, methods and units.     

Quality assurance and statistical control

In scientific research laboratories it is rarely possible to use quality assurance schemes, developed for large-scale analysis. Instead methods have been developed to control the quality of modest numbers of analytical results by relying on statistical control: Analysis of precision serves to detect analytical errors by comparing thea priori precision of the analytical results with the actual variability observed among replicates or duplicates. The method relies on the chi-square distribution to detect excess variability and is quite sensitive even for 5–10 results. Interference control serves to detect analytical bias by comparing results obtained by two different analytical methods, each relying on a different detection principle and therefore exhibiting different influence from matrix elements; only 5–10 sets of results are required to establish whether a regression line passes through the origo. Calibration control is an essential link in the traceability of results. Only one or two samples of pure solid or aqueous standards with accurately known content need to be analyzed. Verification is carried out by analyzing certified reference materials from BCR, NIST, or others; their limited accuracy of 5–10% make them less suitable for calibration purposes.     

Needs for reliable analytical methods for monitoring chemical pollutants in surface water under the European Water Framework Directive

The state of the art in monitoring chemical pollutants to assess water quality status according to Water Framework Directive (WFD) and the challenges associated with it have been reviewed. The article includes information on environmental quality standards (EQSs) proposed to protect the aquatic environment and humans against hazardous substances and the resulting monitoring requirements. Furthermore, minimum performance criteria for analytical methods and quality assurance issues have been discussed. The result of a survey of existing standard methods with a focus on European (EN) and international standards (ISO) for the analysis of chemical pollutants in water is reported and the applicability of those methods for the purpose of compliance checking with EQSs is examined. Approximately 75% of the 41 hazardous substances for which Europe-wide EQSs have been proposed can be reliably monitored in water with acceptable uncertainty when applying existing standardised methods. Monitoring in water encounters difficulties for some substances, e.g., short-chain chlorinated paraffins (SCCPs), polybrominated diphenyl ethers (PBDEs), tributyltin compounds, certain organochlorine pesticides and six-ring PAHs, mainly due to a lack of validated, sufficiently sensitive methods that are applicable in routine laboratory conditions. As WFD requires monitoring of unfiltered samples for organic contaminants more attention needs to be paid to the distribution of chemical pollutants between suspended particulate matter and the liquid phase. Methods allowing complete extraction of organic contaminants from whole water samples are required. From a quality assurance point of view, there is a need to organise interlaboratory comparisons specifically designed to the requirements of WFD (concentrations around EQSs, representative water samples) as well as field trials to compare sampling methodologies. Additional analytical challenges may arise when Member States have identified their river basin specific pollutants and after revision of the list of priority substances.     

Assessment of reproducibility and uncertainty of food microbiology methods: statistical approach of a multi-site laboratory

The validation of food microbiology methods and assessment of measurement uncertainty are required for laboratories operating EN ISO/IEC 17025 accreditation systems. This paper aims to describes the statistical approach adopted by a multi-site laboratory to satisfy these requirements and to routinely check the performance of the methods. A validation protocol was performed, reflecting a great variability of experimental conditions, represented by the period of time during which determinations were made, the different laboratories concerned, the large number of technicians involved, the differences in the level of contamination of the matrix analyzed and the operating conditions (equipment, reagents, culture media, environmental conditions, etc.). Despite the very high variability of the experimental conditions, the values of repeatability and reproducibility obtained for the methods were lower than those stated in the respective regulations. In addition, the top-down approach adopted in this study is to be considered effective overtime and allows to randomize all variable factors, including the effects of sensitivity and specificity, in order to simulate the conditions of real reproducibility. A specific Excel spreadsheet was also developed for the routine expression of analytical results. This spreadsheet represents a very useful tool for operators to calculate and routinely check the results, as well as to assess the uncertainty of measurement. This particular quality assessment system is enabling the multi-site laboratory to implement the accuracy, reliability and comparability of the analytical results and to ensure the analytical control of data output.     

Practical uses of proficiency testing as valuable tools for validation and performance assessment in environmental analysis

Besides their role as an external quality control tool, PT results or samples could be used as an alternative to fulfil some of the quality assurance requirements such as analytical precision, uncertainty assessment, and internal quality control. This additional use of proficiency testing could help laboratories to reduce the financial impact of their quality assurance process. The purpose of this paper is to highlight some practical uses of PT results or samples in the environmental analytical field, which have been implemented at ISSeP (Institut Scientifique de Service Public), either for method validation or for internal quality control.Presented at the Eurachem PT Workshop September 2005, Portorož, Slovenia     

QASKI – the quality assurance system of the National Institute of Chemistry

 The quality assurance system (QASKI) developed and implemented in the National Institute of Chemistry is presented. It tries to eliminate the incompatibilies between the present methods of quality assurance used in research and development institutes such as good laboratory practice and accreditation. Since 1991, QASKI has been used for internal accreditation of laboratories located in the institute, regardless of the fact that some of them deal with routine analyses and others with research and development. Every laboratory that wishes to ensure the credibility of its research or routine work enters QASKI and at the same time chooses an external method of approval. All interested laboratories, study directors, principal investigators, internal auditing staff, heads of documentation, quality assurance unit staff, the Director of the institute and the Quality Management Board participate in the internal system.     

Electrophoretic methods for separation of nanoparticles

This article reviews progress in the application of electrophoretic techniques for the separation of nanoparticles. Numerous types of nanoparticles have recently been synthesised and integrated into different products and procedures. Consequently, analytical methods for the efficient characterisation of nanoparticles are now required. Several studies have revealed that gel electrophoresis can readily be used for separating nanoparticles according to their size or shape. However, many other studies focused on separation of nanoparticles by CE. In some cases nanoparticles could be separated by CZE, simply using pure buffer as the BGE. In other studies, buffer additives (most often SDS) were used, enabling fast separations of metallic nanoparticles by size. Other CE methods also allowed for separation of nanoparticle conjugates with biomolecules. Dielectrophoresis is yet another electrophoretic technique useful in separation and characterisation of nanoparticles; particularly nanotubes. Detection methods often used after electrophoretic separation include UV/Vis absorption and fluorescence spectroscopy. Examples of recent and relevant older reports are presented here. The authors conclude that electrophoretic methods for nanoanalysis can provide inexpensive and efficient tools for quality assurance and safety control; and as a consequence, they can augment transfer of nanotechnologies from research to industry.