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Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement (v.4, #7)
The quality approach and fundamental research: Working towards a constructive alliance (Part I) by Jean-Claude Petit (pp. 274-279).
The quality approach is being progressively used in scientific research and is likely to become a key point in the future. This article critically examines the applicability of the quality approach to fundamental research. A critical survey of the basic concepts of the quality approach is proposed (conformity to a reference, satisfaction of requirements and/or adaptation to use, planning and formalization). The need for quality in fundamental research is then discussed through a review of the scientific, economic and financial, human, social and environmental issues that research will face in the future. An attempt is made to demonstrate that the quality approach incorporates concerns and current practices of the scientific community which are not normally identified and labelled as pertaining to the field of Quality.
Keywords: Key words Quality; Fundamental research; Basic concepts; Impact of quality
The correlation of laboratory performance in proficiency testing with other QA characteristics by B. King; N. Boley; G. Kannan (pp. 280-291).
Although it seems self-evident that proficiency testing (PT) and accreditation can be expected to improve quality, their relative benefits remain uncertain as does their efficacy. The study reported here examines the following issues: (a) Why do laboratories take part in PT schemes? (b) How does participation in PT fit in with a laboratory's overall quality assurance (QA) system? (c) Is there a link between a laboratory's performance in specific PT and it's QA system? (d) How does PT performance change with time and how do laboratories respond to poor performance? The overall conclusion is that there is no evidence from the present study that laboratories with third-party assessment (accreditation and certification) perform any better in PT than laboratories without. The validity of this conclusion and its significance for the future design and operation of such schemes requires further investigation. In particular, study is required of the degree to which good performance in open PT correlates with blind PT performance, where laboratories are not aware that the samples being analysed are part of a quality assessment exercise.
Keywords: Key words Quality assurance; Proficiency testing; Accreditation; Analytical measurements
Detection of genetically modified organisms in food: critical points for quality assurance by P. Hübner; Edgar Studer; Daniel Häfliger; Markus Stadler; Christian Wolf; Martin Looser (pp. 292-298).
The detection of genetically modified organisms (GMOs) by the polymerase chain reaction (PCR) is a complex multiparameter problem. Therefore, a number of critical issues in respect to quality control need to be considered. For practical purposes, the PCR process itself can be divided into three subprocesses: template isolation and reaction setup (pre-PCR), PCR reaction and detection of amplification products, and data evaluation (post-PCR). Crucial factors for the pre-PCR process are the following: homogeneity of the sample to be analysed, performance of template isolation and purification in terms of yield and purity, standardized process for the estimation of concentrations of genomic DNA and all reagents used in the reaction. For the PCR itself, crucial factors to be controlled are: setup of reactions, batch to batch variations of reagents, temperature-time programs used for the PCR amplification, and the performance of different types of hardware (e.g. different brands of thermocyclers). The crucial factor for the post-PCR process is the detection of the amplification products of the PCR. The tremendous sensitivity of PCR methods requires a careful and consequent separation of the three processes in terms of hardware, laboratory space and sample handling. The avoidance of contamination is one of the most critical factors. The goal of quality assurance measures must be to ensure appropriate results at maximum sensitivity. The complexity of any PCR system used for the detection of GMOs leads to the requirement of a careful validation process for any laboratory using such methods. For qualitative analyses crucial validation parameters are: specificity, selectivity, repeatability, intermediate precision, reproducibility, limit of detection and robustness.
Keywords: Key words GMO detection; PCR; Food labelling; Quality assurance
Current interlaboratory precision of exchangeable soil fraction measurements by Manfred Sager (pp. 299-306).
In addition to conventional aqua regia and EDTA extracts for monitoring trace metals in soils, the technique of examining exchangeable soil fractions has been suggested to estimate soil contamination and trace metal availability to plants. In order to establish a useful method for soil monitoring, interlaboratory precision as a primary selection criterion has been investigated. In order to assess the quality of data provided by laboratories participating in the organization of the Austrian Governmental Agricultural Research Institutes (ALVA), three soil samples have been analysed in a common ring test, annually, for the last 20 years. In addition to the annual list of parameters used for soil monitoring, within ALVA two NH4-acetate extracts were run in 1994, three NH4-acetate and NH4NO3 extracts in 1995 and three LiCl extractions in 1998. The procedures were tested for analytical precision and environmental indications in up to 12 laboratories, with respect to Cd, Cr, Cu, Ni, Pb and Zn. Due to the low extraction efficiency, for determinations in the resultant solutions, graphite furnace AAS was preferably selected, except for Zn and Cu. Flame-AAS and ICP-OES were not sensitive enough for non-contaminated sites. Interlaboratory precision of the data was in the range 10–65% coeff.var., and thus within the range of data given in the appendix of DIN 19730 (NH4NO3), as well as in a previous BCR report. Indications from exchangeable fractions seemed to be good for Zn and Cu, whereas they were impossible for Cr.
Keywords: Key words Interlaboratory precision; Trace metals; Exchangeable fractions in soils; Harmonized procedure
Preparation and testing of standard solutions of cadmium, copper and lead by O. Mestek; Miloslav Suchánek; Vojtěch Hrubý (pp. 307-312).
Solutions of Cd, Cu and Pb at concentrations of about 1000 mg/l were prepared by dissolving the pure metals in HNO3. Their concentration was verified by complexometric titration and by gravimetric analysis (Cu with salicylaldoxime, Cd with quinaldinic acid and Pb with 8-hydroxyquinoline). The results of the two methods were very similar and the uncertainty values were equal. However, the gravimetric determination can be regarded as more reliable, because titrimetric analysis is more prone to error due to inaccurate end-point reading. The expanded uncertainty of the concentrations of Cd and Cu attained 1 mg/l, which is half the value typically obtained for similar solutions from commercial manufacturers. To achieve such precise results, the bias had to be reduced by the highest possible extent, particularly by calibrating both the balance and the volumetric glassware. In addition to the uncertainty of the basic operations (volumetric and gravimetric), the uncertainty of the atomic and molecular weights constituted an appreciable component in the combined standard uncertainty; this manifested itself in the determination of Pb, where the expanded uncertainty was 2 mg/l.
Keywords: Key words Standard solution; Lead; Copper; Cadmium; Uncertainty