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1.
Bioanalytical method validation and its implications for forensic and clinical toxicology – A review
The reliability of analytical data is very important to forensic and clinical toxicologists for the correct interpretation
of toxicological findings. This makes (bio)analytical method validation an integral part of quality management and accreditation
in analytical toxicology. Therefore, consensus should be reached in this field on the kind and extent of validation experiments
as well as on acceptance criteria for validation parameters. In this review, the most important papers published on this topic
since 1991 have been reviewed. Terminology, theoretical and practical aspects as well as implications for forensic and clinical
toxicology of the following validation parameters are discussed: selectivity (specificity), calibration model (linearity),
accuracy, precision, limits, stability, recovery and ruggedness (robustness).
Received: 16 June 2002 Accepted: 12 July 2002
Part of this review was published in the communications of the International Association of Forensic Toxicologists (TIAFT;
TIAFT Bulletin 32 (2002): 16–23) and of the Society for Forensic and Toxicologic Chemistry (GTFCH; Toxichem and Krimitech
68 (2001): 116-126).
Correspondence to F. T. Peters 相似文献
2.
M. H. Feinberg Alice Gerbanowski D. N. Rutledge 《Accreditation and quality assurance》1997,2(2):69-75
Method validation procedure requires a strategy for collecting those validation data that are best adapted to the analytical
technique used. A flexible and general approach based on Object Linking and Embedding technology is proposed. It allows a
traceable validation strategy using modular objects which encapsulate documentation, analytical data and processing logic.
The contents of these objects are accessible through a standard user interface. This paper demonstrates how this can reduce
experiment time, simplify evaluation efforts, and increase the ease of use of validation figures of merit. An illustration
using Microsoft Visual Basic for Applications is presented, and some specific aspects are described. It consists of the evaluation
of a time domain NMR technique for determining the moisture content of foods involving a multivariate calibration step. This
study also illustrates how guidelines such as Good Validation Practices could be defined to present all validation documents
in a standardised manner.
Received: 3 September 1996 Accepted: 14 October 1996 相似文献
3.
N. Majcen 《Accreditation and quality assurance》2003,8(3-4):108-112
The fact that various definitions and terminology applied to measurements in analytical chemistry are not always consistent
and straightforward, by not only answering the question ”what”, but also ”how”, leads to their various interpretations. This
results in non-uniform implementation of very basic and essential metrological principles in chemistry. Such a diverse situation
is not conducive to the endorsement of harmonised measurements all across the world, to serve as a tool for improving the
quality of life in its broadest sense for all its citizens. The discussion in this paper is focused on problems associated
with terminology and definitions of ’reference material’ and ’validation’. The role of reference materials in measurement
processes for purposes other than calibration and validation principles in analytical chemistry are also discussed in this
paper. Where possible, potential solutions are proposed, but more often, questions of essential importance are raised in order
to initiate international discussion which will hopefully lead to equally understandable answers.
Received: 2 November 2002 Accepted: 3 February 2003
Acknowledgements
The author is grateful to Aleš Fajgelj for his comprehensive comments on the topic described in this paper. Sincere thanks
also to Philip Taylor, Ewa Bulska, Emilia Vassileva, Miloslav Suchanek and Margreet Lauwaars for their contribution during
fruitful discussions on validation.
Presented at the CERMM-3, Central European Reference Materials and Measurements Conference: The function of reference materials
in the measurement process, May 30–June 1, 2002, Rogaška Slatina, Slovenia
Correspondence to N. Majcen 相似文献
4.
A. M. H. van der Veen A. Alink D. Verkuil B. van der Lecq 《Accreditation and quality assurance》1996,1(5):207-212
Working group 5 of EuraChem Nederland has developed a framework for the implementation of reference materials in analytical
chemistry. In this discussed paper, the framework is proposed as a tool for the development of standard operation procedures
(SOPs) in laboratories. The implementation of (certified) reference materials in these SOPs is of major importance in establishing
comparability and traceability in measurement results, which in turn play a crucial role in measurement in support of trade,
environmental issues, and characterisation of materials. Recent developments in the field of uncertainty analysis require
the application of reference materials. It is recognised that the calculation of the combined measurement uncertainty becomes
almost impossible without the use of certified reference materials with a stated uncertainty.
Received: 1 December 1995 Accepted: 20 December 1995 相似文献
5.
Raphael Bar 《Accreditation and quality assurance》1999,4(6):235-239
Stability assay results of a stable solid oral dosage form, designated Product X 5 mg, were subjected to a statistical analysis
in view of evaluating the intra-team repeatability and the interval-to-interval reproducibility of the analytical method.
Analysis of variance and analysis of method capability were performed on stability data obtained from tablets stored in four
different packages over a two-year period. Replicate-to-replicate and period-to-period standard deviations of assay results
of the active drug ingredient were found to vary among the packages and were up to 1.3 and 1.5% (% assay), thus leading to
maximum differences between any two reported average results of up 4.7%. Analysis of method capability showed that up to 51%
of the specification range (90–110%) is taken up by variations of the reported average stability results. This large but realistic
method variability does not reflect the formation of low-level impurities (ca. 0.1%) required by regulatory agencies.
Received: 10 December 1998 · Accepted: 25 January 1999 相似文献
6.
A strategy is presented for applying existing data and planning necessary additional experiments for uncertainty estimation.
The strategy has two stages: identifying and structuring the input effects, followed by an explicit reconciliation stage to
assess the degree to which information available meets the requirement and thus identify factors requiring further study.
A graphical approach to identifying and structuring the input effects on a measurement result is presented. The methodology
promotes consistent identification of important effects, and permits effective application of prior data with minimal risk
of duplication or omission. The results of applying the methodology are discussed, with particular reference to the use of
planned recovery and precision studies.
Received: 28 October 1997 · Accepted: 17 November 1997 相似文献
7.
R. C. Díaz M. A. Sarasa C. Ríos J. J. Cuello 《Accreditation and quality assurance》1999,4(11):473-476
The determination of dichlorobenzene and naphthalene in commercial repellents used in Spain has been validated. This was
done using an isocratic regime, to test the reverse -phase HPLC system with acetonitrile: water 65 : 35 (v: v) as the mobile
phase, at 20 °C. This technique is proposed for the modular validation of the HPLC system . The results obtained with this
method show good agreement with the results provided by the manufacturers of the mothrepellents.
Received: 21 December 1998 / Accepted: 4 May 1999 相似文献
8.
Klaus Reber 《Accreditation and quality assurance》1999,4(4):156-157
The Swiss Federal Laboratories for Materials Testing and Research (EMPA) have established a quality assurance system based
on EN 45001 which meets the requirements for accreditation of all EMPA's testing activities. As testing is only a part of
EMPA's range of activities, and is performed in decentralised departments, the system does not satisfy the management needs.
The fundamental reorganisation of EMPA's St. Gallen site was used as an opportunity to implement an overall process-oriented
management system which also included quality and the needs for accreditation. Later, an environmental management system was
added and then certified for ISO 9001 and 14001. The system consists of a "Management Manual" for the St. Gallen site and
a customised "Quality Manual" for each department. One of the key elements is a comprehensive review and planning procedure
covering all business aspects. 相似文献
9.
A practical approach to assessment of sampling uncertainty 总被引:1,自引:0,他引:1
Paolo de Zorzi Maria Belli Sabrina Barbizzi Sandro Menegon Andrea Deluisa 《Accreditation and quality assurance》2002,7(5):182-188
The paper reports the approach followed in the SOILSAMP project, funded by the National Environmental Protection Agency (ANPA)of
Italy. SOILSAMP is aimed at assessing uncertainties associated with soil sampling in agricultural, semi-natural, urban, and
industrial environments. The uncertainty assessment is based on a bottom-up approach, according to the Guide to the Expression
of Uncertainty in Measurement published by the International Organization for Standardization (ISO). A designated agricultural
area, which has been characterized in terms of elemental spatial distribution, will be used in future as a reference site
for soil sampling intercomparison exercises.
Received: 19 November 2001 Accepted: 6 January 2002 相似文献
10.
Reinout Heijungs Gjalt Huppes Jeroen B. Guinée 《Polymer Degradation and Stability》2010,95(3):422-1719
There are many approaches to study the environmental and sustainability aspects of production and consumption. Some of these reside at the level of concepts, e.g., industrial ecology, design for environment, and cleaner production. Other approaches are based on the use of quantitative models, e.g., life cycle assessment, material flow accounting and strategic environmental assessment. This paper focuses on the development of a framework that is able to incorporate different models for environmental analysis, with the option of a broader scope that also includes economic and social aspects, thus covering the three pillars of sustainability. This framework builds on the ISO-framework for life cycle assessment, but takes a broader view, and allows us to move from micro questions on specific products, via meso questions on life styles up to macro questions in which the entire societal structure is part of the analysis. 相似文献
11.
Limits of detection, identification and determination: a statistical approach for practitioners 总被引:3,自引:0,他引:3
For the estimation of the limits of detection, identification and determination, considerations from analytical practice
were applied to the statistics of the calibration line and its prediction interval. The detection limit was the concentration
calculated from the maximum height of the prediction interval at zero spiking concentration. The identification limit was
twice the detection limit and was the lowest concentration that could safely be detected. The determination limit was the
lowest concentration fulfilling three criteria: 1. None of the signals resulting from determination limit concentration should
interfere with any signal from detection limit concentration, thus providing an unambiguous separation between the two limits.
2. Recovery should be between 70% and 120%. 3. Lowest and highest predictable signal at determination limit concentration
should not deviate more than ± 30% from the average. Practical analytical guidance and the necessary mathematical formulae
are presented.
Received: 12 November 1997 · Accepted: 7 December 1997 相似文献
12.
We present a method to treat the solvent efficiently in hybrid quantum mechanical/molecular mechanical simulations of chemical
reactions in enzymes. The method is an adaptation of an approach developed for molecular-mechanical free-energy simulations.
The charges of each of the exposed ionizable groups are scaled, and the system is simulated in the presence of a limited number
of explicit solvent molecules to obtain a reasonable set of structures. Continuum electrostatics methods are then used to
correct the energies. Variations in the procedure are discussed with an emphasis on modifications from the original protocol.
We illustrate the method by applying it to the study of a hydrolysis reaction in a highly charged system comprising a complex
between the base excision repair enzyme uracil-DNA glycosylase and double-stranded DNA. The resulting adiabatic reaction profile
is in good agreement with experiment, in contrast to that obtained without scaling the charges.
Received: 5 October 2001 / Accepted: 6 September 2002 / Published online: 28 February 2003
Contribution to the Proceedings of the Symposium on Combined QM/MM Methods at the 222nd National Meeting of the American
Chemical Society, 2001
Correspondence to: M. Karplus e-mail: marci@tammy.harvard.edu 相似文献
13.
A simple method to prepare solid nanoparticles of water-soluble salts using water-in-oil microemulsions 总被引:7,自引:0,他引:7
A new and simple method to prepare solid nanoparticles of water-soluble salts using water-in-oil microemulsions is described.
In particular, starting from water/sodium bis(2-ethylhexyl)sulfosuccinate/n-heptane microemulsions carrying inside the aqueous core of the reversed micelles some water-soluble salts [CaCl2, Na2HPO4, Cu(NO3)2], after evaporation of the volatile components (water and apolar organic solvent), the resulting inorganic salt/surfactant
composites were found to be totally dispersible in pure n-heptane. The presence of nanoparticles in these resuspended composites was ascertained by transmission electron microscopy
observation of samples obtained by gentle evaporation of the organic solvent.
Received: 8 July 1999/Accepted in revised form: 5 October 1999 相似文献
14.
A. Steinhorst 《Accreditation and quality assurance》1998,3(7):294-295
DACH, the German accreditation body of chemistry, which was founded in 1992, has introduced a new model for the flexibilization
of the scope of accreditation. This ensures that the accreditation of a laboratory also guarantees flexibility. Flexibilization
of the scope of accreditation is of great importance, in particular if a great number of similar routine tests (standard methods)
or non-routine tests are to be accredited. The main tool of flexibilization is the accreditation of types of tests. The accreditation
of types of tests entitles laboratories to include additional test methods within the type of test accredited without informing
the accreditation body immediately. Such information is provided at fixed surveillance intervals. The conditions for the accreditation
of types of tests are described below. 相似文献
15.
A protocol has been developed illustrating the link between validation experiments, such as precision, trueness and ruggedness
testing, and measurement uncertainty evaluation. By planning validation experiments with uncertainty estimation in mind, uncertainty
budgets can be obtained from validation data with little additional effort. The main stages in the uncertainty estimation
process are described, and the use of trueness and ruggedness studies is discussed in detail. The practical application of
the protocol will be illustrated in Part 2, with reference to a method for the determination of three markers (CI solvent
red 24, quinizarin and CI solvent yellow 124) in fuel oil samples.
Received: 10 April 1999 / Accepted: 24 September 1999 相似文献
16.
The methodology of evaluating the performance of sampling, sample preparation, and subsampling is reviewed. The requirements
to be set for a successful experiment are revisited. The central role of the reference method is explained, and so is the
choice of the parameters and the measurement methods. Based on the principles of the "Guide to the expression of uncertainty
in measurement" (GUM), a statistical model is developed that demonstrates the influence of the experimental design on the
outcome of the assessment experiment. This relationship is often overlooked in practice, as it is hardly mentioned in written
standards dealing with this kind of quality assessments. The statistical framework thus developed covers the statistical procedures
commonly appearing in written standards. Finally, the issue of testing the significance of the bias obtained from the experiment
is discussed.
Received: 14 June 1997 · Accepted: 2 September 1997 相似文献
17.
18.
R. J. Wells 《Accreditation and quality assurance》1998,3(5):189-193
Although the validation process necessary to ensure that an analytical method is fit for purpose is universal, the emphasis
placed on different aspects of that process will vary according to the end use for which the analytical procedure is designed.
It therefore becomes difficult to produce a standard method validation protocol which will be totally applicable to all analytical
methods. It is probable that far more than 30% of the methods in routine laboratory use have not been validated to an appropriate
level to suit the problem at hand. This situation needs to change and a practical assessment of the degree to which a method
requires to be validated is the first step to a reliable and cost effective analytical industry.
Received: 22 September 1997 · Accepted: 28 November 1997 相似文献
19.
Z. Dobkowski 《Accreditation and quality assurance》1997,2(8):381-387
Some problems of validation of computerised instruments are reviewed briefly, taking essential standards and guides into
account. The significant role of certified standard reference materials is underlined. An attitude of suppliers towards the
validation of instruments is presented, and producers' responsibilities and obligations are discussed. The "black-box" concept
is recommended as a preliminary step for the validation of computerised instruments. Two examples for gel permeation chromatography
are given that illustrate a bad manufacturer's practice (BMP) and good manufacturer's practice (GMP). In the case of BMP,
a need is expressed for a guide and for regulations that should be implemented into the quality assurance system. It has been
proposed that the EURACHEM/VAM draft of guidance for qualification/validation of instruments should be amended by incorporating
the "black-box" approach as a preliminary procedure for validation of computerised instruments, a retrospective validation
procedure if the need for current validation was not foreseen or not specified, and a procedure (or selection rules) for qualification
of the supplier. Moreover, the mechanisms of inspection to control the observance of the standardised rules and commonly recognised
recommendations should also be considered by international quality organisations.
Received: 19 November 1996 · Accepted: 20 March 1997 相似文献
20.
T. Iwaoka 《Accreditation and quality assurance》1997,2(3):146-149
Analytical laboratories in Japan, operating more often as departments within a company than as independent contractors, have
to contend with different good laboratory practice (GLP) standards. Problems also occur in the analytical laboratories which
must comply with GLP, good manufacturing practice (GMP) and good clinical practice (GCP) regulations within the same facility.
The status of these GLP-complied analytical laboratories is reviewed with regard to assurance program, validation method,
laboratory information management, and security systems. The differences in the responsible authorities and scopes under the
six GLPs are also briefly described. Analytical tests in GLP are not itemized as a test for accreditation. Therefore, the
accreditation of analytical laboratories in Japan is currently granted as a part of ISO 9000 approvals.
Received: 27 September 1996 Accepted: 11 November 1996 相似文献