共查询到20条相似文献,搜索用时 15 毫秒
1.
Mary M. Kimberly 《Accreditation and quality assurance》2004,9(4-5):239-241
In 1968, clinical chemistry was considered to be the field most in need of certified reference materials (CRMs). While significant progress has been made in this area, new diagnostic assays are continually being developed that create a need for new CRMs. Members of the clinical laboratory community help to identify reference material needs. Professional and governmental organizations, such as IFCC, AACC, NCCLS, CDC, and the national metrological institutes (NMIs), respond to develop protocols and materials. Several measurands are presented as examples. In the late 1950s and early 1960s, in response to a need for standardization of lipid and lipoprotein measurements, CDC developed a reference system that included secondary reference materials. Over the years, the process of preparation of these materials was refined, eventually leading to the development of NCCLS guideline for preparation of commutable frozen serum pools for use as secondary reference materials (C37-A). This protocol was used for the preparation of NIST SRM 1951a (lipids in frozen (liquid) human serum). In the 1980s, a need for a reference material for blood lead was identified. CDC and NIST cooperated to develop SRM 955 (lead in bovine blood). More recently, efforts have been initiated to standardize high-sensitivity C-reactive protein (hsCRP) assays. In this case, a CRM for CRP existed (CRM 470, developed by IFCC and available from IRMM), but at concentrations in the acute phase reactant range and not in the low range needed for hsCRP assays. CDC coordinated a study to evaluate diluted CRM470 and other candidate materials as secondary reference materials for hsCRP assays.Presented at BERM-9—Ninth International Symposium on Biological and Environmental Reference Materials, June 15–19, 2003, Berlin, Germany. 相似文献
2.
标准物质在检测实验室质量控制中的应用 总被引:1,自引:0,他引:1
【】 本文介绍了检测中使用标准物质进行质量控制的重要意义,分别在盲样测试、期间核查和质量控制图应用方面提出了使用标准物质进行质量控制的三种方法,并通过在实验室获得的检测数据对上述应用方法作了实例说明,对检测实验室应用标准物质进行质量控制工作具有指导意义。 相似文献
3.
Quality control materials (QCMs) to be used in daily quality control in environmental laboratories are required to be similar to real samples in terms both of composition and of physical state. The present paper describes in detail the procedure of preparation and the results of homogeneity and stability studies performed on wet sediments QCMs. For this purpose, two sediments with different matrix composition were selected and the main factors involved in the preparation of the material were carefully studied and established with the aim of guaranteeing long-term stability of the QCM: pre-treatment steps, homogenisation, bottling and storage. The results obtained from the homogeneity and from 12 months of stability studies for Cd, Cr, Cu, Ni, Pb and Zn following the aqua regia extraction procedure (ISO 11466), showed that the wet sediment QCMs we have developed are feasible, constituting a new and useful material among the aquatic sediments for quality control purposes in monitoring. 相似文献
4.
Marina Patriarca Ferdinando Chiodo Marco Castelli Federica Corsetti Antonio Menditto 《Microchemical Journal》2005,79(1-2):337
The Me.Tos. Project, started in 1983 and still running, is an external quality assessment (EQA) scheme for laboratories performing specialized analyses in occupational and environmental laboratory medicine. Besides the organization of EQA exercises, initiatives for further education of the participants and the harmonization of EQA procedures at a European level are carried out. Participation in EQA schemes allows laboratories to comply with the international standards for the quality and competence of testing and clinical laboratories. The organization of the scheme includes the preparation of control materials, their distribution to the participants, according to strategies aimed to avoid identification of the samples, the statistical analysis of the results and the evaluation of laboratories' performance according to international guidelines and criteria set by the organizers. An overview of the scheme operation and the current performances of participants will be given. 相似文献
5.
Byzova NA Zvereva EA Zherdev AV Eremin SA Sveshnikov PG Dzantiev BB 《Analytica chimica acta》2011,(2):627-217
A rapid pretreatment-free immunochromatographic assay was developed for the control of the streptomycin (STR) content in milk and dairy products. The assay is based on the competition between an immobilized STR–protein conjugate and STR in a sample to be tested for the binding to monoclonal anti-STR antibodies conjugated to colloidal gold during the flow of the sample along a membrane strip with immobilized reactants. It is possible to improve the cut-off level of positive and negative samples distinguished by a change in the molar STR to protein ratio in the immobilized conjugate. The cut-off level (500 ng mL−1) thus achieved corresponds to the stated MRL of STR in milk and dairy products. For STR concentrations in the range of 16–250 ng mL−1 its content can be quantitatively measured based on the degree of binding of a colloidal gold label in the test strip zone with the immobilized STR–protein conjugate. The duration of the assay is 10 min. The selected sizes of membrane pores and colloidal gold particles allow the assay to be carried out at room temperature without additional reactants and pretreatment. The applicability of the assay for milk, whole milk, sour clotted milk, and kefir with different fat content (from 0.5% to 6%) was confirmed. The results of quantitative immunochromatographic assay show good correlation with traditional ELISA (r was equal to 0.935 and 0.940 for the series tested). 相似文献
6.
Reference materials have been applied widely to ensure the traceability, comparability and reliability of measurement results.
To achieve this purpose, the quality of reference materials (RMs) themselves is surely an important aspect to be pay attention
to. A quality evaluation system of RMs has been established through the project “The National Sharing Platform of Reference
Materials” in China to give a reliable assessment on the quality of RMs from various sources including the accuracy and comparability
of their property values, which is very useful to promote the appropriate selecting and using of RMs in China. Through the
application of National Metrology Institute calibration and measurement capabilities on the basis of the international mutual
recognition arrangement, it can also provide a powerful supplement to the current activities such as the accreditation of
RM producers in the construction of a global harmonized quality control and assurance system of RMs. 相似文献
7.
N. Etxebarria G. Arana R. Antolín G. Borge T. Posada J. C. Raposo 《Accreditation and quality assurance》2007,12(11):575-580
Electrolytic manganese is an important alloying element for aluminium and steel melts. It is mainly added to melts of aluminium
in the holding furnace as tablets or minitablets (compressed compacts of manganese and aluminium powders). Selenium derivates
are usually added during the production of electrolytic manganese, so some selenium is present in the alloys produced when
electrolytic manganese is added to the aluminium furnace. Since the selenium contents of many alloys are of concern from health
and environmental perspectives, their values should be provided. In this work, a laboratory reference material (LRM) based
on electrolytic manganese was produced to assure our routine quality control method, where selenium is analysed by hydride
generation followed by optical emission spectrometry with inductively coupled plasma (HG–ICP–OES). Therefore, the present
paper describes in detail the preparation procedure for and the results from homogeneity and stability studies performed on
electrolytic manganese LRM. For this purpose, a commercial electrolytic manganese lot was selected and the main factors involved
in the preparation of the material (pretreatment step, homogenization, bottling and storage) were carefully studied and established
in order to guarantee the long-term stability of the LRM. The results obtained showed that the LRM developed was a fit-for-purpose
material for the quality control of the routine analysis of selenium. 相似文献
8.
Hermann Glaeser 《Accreditation and quality assurance》2004,9(4-5):205-208
Foodstuffs shall not contain pathogenic micro-organisms in concentrations which may cause a risk for consumer health. The relevant legislation therefore normally contains the requirement that these organisms are absent in a certain product quantity (e.g. 25 g). It is not at all easy to prove the absence. Reference materials are important tools for checking the performance of qualitative methods. These materials should contain the target organism in low numbers (close to 1 cell/capsule). Furthermore, the most important interfering micro-organisms should be taken into consideration, when testing the performance of detection methods using reference materials. When developing reference materials with the described characteristics, detection methods are needed which give a positive result with one or a few cell(s) of the target organism. While these requirements appear to be fairly obvious, precise statements on method performance are rarely available. Strategies to obtain this information are discussed. Further important aspects are practical considerations when using such reference materials for method evaluation. Statistical procedures can help to obtain the relevant information with a minimum of effort.Presented at BERM-9—Ninth International Symposium on Biological and Environmental Reference Materials, June 15–19, 2003, Berlin, Germany. Views expressed in this paper represent the personal opinion of the author. 相似文献
9.
Amaia Guevara-Riba Angels Sahuquillo Roser Rubio Gemma Rauret 《Accreditation and quality assurance》2007,12(5):241-248
The implementation of the European Water Framework Directive (WFD) and of the sediment-quality criteria related to the potential
disposal of dredged materials is expected to involve a substantial increase in the number of chemical analyses performed in
marine environmental control laboratories. The chemical characterization of sediments (metals, elemental composition, etc.)
and the potential release of metals under changing environmental conditions are relevant when dealing with risk assessment.
The present paper describes the preparation of a quality control material (QCM) harbor sediment carried out in a specifically
equipped laboratory at the University of Barcelona. The results of homogeneity and stability studies for total metal content
(Cd, Cr, Cu, Ni, Pb, and Zn), extractable metal following the BCR three-step sequential extraction procedure (BCR-SEP), and
total carbon content show the suitability of QCM for multi-parameter routine quality control (QC) in marine environmental
laboratories. 相似文献
10.
Aflatoxin M1 (AFM1), a highly toxic secondary metabolite, is present in a wide range of dairy products. In this study, we designed a simple, low-cost, reusable, and easy-to-operate immunosensing method for ultrasensitive detection of AFM1 in dairy products by using a portable evanescent wave-based optofluidic biosensing platform (EOBP). The developed method provides the minimum detection limit of 5 ng/L, which is below the most restrictive standard imposed by the current regulations for AFM1 in dairy products. The effect of several organic solvents, such as methanol, acetone, and acetonitrile, on the binding reaction of antibody-antigen in heterogeneous and homogeneous solutions was evaluated. Although the effect of organic solvents on the homogeneous binding reaction between antibody and antigen is more significant than that of heterogeneous binding reaction between antibody in solution and antigen immobilized onto the sensor surface, the fluorescence signal detected by EOBP is linearly dependent on AFM1 concentration. Therefore, AFM1 can be directly quantified even if the samples contain a certain organic solvent concentration. The robustness and stability of AFM1-ovalbumin conjugate allow the regeneration of modified biosensor surface for more than 200 times, thereby achieving a cost-effective and reliable AFM1 determination. The proposed method provides a rapid, ultrasensitive, and reliable AFM1 determination in dairy products without complicated sample pretreatment process. 相似文献
11.
Summary Automatic thermal desorption (ATD) has been evaluated for the analysis of volatile components from dairy products. It has
resulted in a fast and reproducible method which needs only a low amount of sample. Volatile components from milk are collected
by off-line purging and trapped on cartridges packed which a suitable adsorbent. Cheese samples are submitted to the same
process or directly introduced into the cartridges. The desorption step that follows is carried out automatically and on-line
with the chromatographic analysis. Repeatability and sensitivity were satisfactory for both types of products. 相似文献
12.
Molecularly imprinted polymer as SPE sorbent for selective extraction of melamine in dairy products 总被引:2,自引:0,他引:2
In this paper, a highly selective sample cleanup procedure combining molecular imprinting and solid-phase extraction (MI-SPE) was developed for the isolation of melamine in dairy products. The molecularly imprinted polymer (MIP) was prepared using melamine as the template molecule, methacrylic acid as the functional monomer and ethylene glycol dimethacrylate as the cross-linking monomer. The melamine imprinted polymer was used as selective sorbent for the solid-phase extraction of melamine from dairy products. An off-line MI-SPE method followed by high-performance liquid chromatography with diode-array detection for the detection of melamine was also established. The mean recoveries of melamine from ultra-heat treatment (UHT) milk and milk powders were 92.9-98.0% and 91.6-102.8%, respectively. Good linearity was obtained from 0.5 μM to 10 μM (r > 0.999) with a quantitation limit of 0.5 μmol/L (0.06 ppm) which was sufficient to analyse melamine at the maximum level permitted by U.S. Food and Drug Administration (1 ppm) in dairy products. It was demonstrated that the proposed MI-SPE-HPLC method could be applied to direct determination of melamine in dairy products. 相似文献
13.
Michael Zischka Peter SchramelHerbert Muntau Albert RehnertMilagros Gomez GomezBern StojanikGunter Wannemaker Richard DamsPhilippe Quevauviller Eddie A. Maier 《Trends in analytical chemistry : TRAC》2002,21(12):851-868
Certified Reference Materials (CRMs) represent a key tool for the quality control of chemical analyses. The demand for environmental materials is constantly increasing in complex analytical fields, and the European Commission (EC) (through the Measurements & Testing Generic Activity) is responding to the urgent needs for materials requiring collaborative efforts at the international level. This paper describes the preparation of a new road-dust material (BCR-723), along with homogeneity and stability studies and the analytical work performed for the certification of the contents of palladium, platinum and rhodium, under the EC's PACEPAC project, PACEPAC being the acronym for “Production And CErtification of a road dust reference material for Platinum, palladium and rhodium used in Automotive Catalytic converters”. 相似文献
14.
The use of (certified) reference materials and quality control materials can form a suitable basis for evaluating measurement uncertainty of routine measurements. In particular when these materials are used for quality control purposes, it is not always evident how the quality control data can be used in the uncertainty budget of a routine measurement. Current guidance documents on the evaluation of measurement uncertainty and the use of reference materials treat this subject only in part, or in very generic terms. ISO/REMCO has established a new working group that will provide practical guidance and examples on how to use quality control data in the evaluation of measurement uncertainty. A short introduction to the subject is given.
相似文献
Adriaan M. H. van der VeenEmail: Phone: +31-15-2691733Fax: +31-15-2691670 |
15.
Tommaso R.I. Cataldi Massimiliano Angelotti Giuliana Bianco 《Analytica chimica acta》2003,485(1):43-49
A simple and sensitive liquid chromatographic method for the separation and quantification of mono- and disaccharides in raw- and processed-milk is described. Samples of cows’, buffalos’, sheeps’ and goats’ milk were analyzed upon clarification and appropriate dilution for the quantification of lactose, galactose, glucose and N-acetylglucosamine (GlcNAc). The separation was accomplished by high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD), using a gold working electrode and dilute alkaline eluents modified by a millimolar concentration of barium acetate. The eluent composition employed was designed to provide optimum separation with respect to the selected sample, without interference from the matrix components. The analytical method was successfully employed for the determination of mono- and disaccharides naturally occurring in dairy milk, mozzarella cheese and whey samples, with high sensitivity and accuracy. 相似文献
16.
In the view of the Deutscher Kalibrierdienst (DKD) , a certifying body for reference materials can be considered to be a calibration laboratory. Therefore, accreditation of calibration laboratories in accordance with ISO/IEC 17025 is the most appropriate way to establish confidence in certificates for reference materials. If necessary, the criteria of ISO/IEC 17025 can be tailored to specific cases. There is no need to provide any new kind of reference-material specific accreditation. However, in view of the variety of reference materials and the practice existing in other countries, accreditation of testing laboratories and product certification bodies may optionally be acceptable as long as the same stringent principles with respect to traceability and measurement uncertainty are applied. Such accreditations but not accreditations of reference material producers (ISO Guide 34) are also covered by existing international mutual recognition arrangements (MRA). 相似文献
17.
This article discusses the requirements for reference materials (RMs) for measuring the size of nanoparticles (NPs). Such RMs can be used for instrument calibration, statistical quality control or interlaboratory comparisons. They can come in the form of suspensions, powders or matrix-embedded materials [i.e. NPs integrated in a natural matrix (e.g., food, soil, or sludge)].At present, uncertainty about the most suitable form of material, the most relevant measurands and the most useful metrological-traceability statement inhibits the production of NP RMs. In addition, the lack of validated methods and qualified laboratories to produce NP RMs present formidable challenges.Metal, inorganic and organic NPs are available, but most of them are intended to be laboratory chemicals. With the exception of latex materials, certified RMs are not available, although some metrology institutes have started to develop such materials for colloidal gold and silica particles. 相似文献
18.
Krska R Schothorst RC van Egmond HP Josephs RD Lepschy J Pettersson H Chan D Berthiller F Schuhmacher R Kandler W Parich A Welzig E 《Analytical and bioanalytical chemistry》2005,382(8):1848-1858
The lack of reliable, certified calibrant solutions for the Fusarium mycotoxins deoxynivalenol (DON), 3-acetyl-DON (3-Ac-DON), 15-acetyl-DON (15-Ac-DON) and nivalenol (NIV) is a serious drawback in the already problematic area of trichothecene analysis. For this reason, purified DON, 3-Ac-DON, 15-Ac-DON and NIV standards were processed, the conditions required for their isolation and purification were optimised, and the crystalline toxins were thoroughly characterised. Several complimentary analytical methods were used to evaluate the identities of the mycotoxins and the types and amounts of impurities; results obtained from 1 H and 13 C NMR spectra, as well as from IR-spectra, were in agreement with the literature. Elemental analysis revealed that the isolated NIV occurs as monohydrate. If this is not known it results in a weighing error of approximately 5%. Differential scanning calorimetry (DSC) was only successful for 15-Ac-DON, as the other trichothecenes decomposed during measurements. No traces of chloride, nitrate and sulphate were found by means of ion chromatography (IC). As expected UV absorption spectra for DON, NIV, 3-Ac-DON and 15-Ac-DON yielded max values of 216, 217, 217 and 219 nm, respectively. Minor peaks due to impurities were observed by high performance liquid chromatography (HPLC) with UV detection. The main impurity peak in the DON sample was identified by LC-tandem mass spectroscopy (LC-MS/MS) as 4,7-dideoxy-NIV (7-deoxy-DON), which occurs at levels of approximately 1.4%. Gas chromatography (GC) was performed, coupled with either an electron capture detector (ECD), a flame ionisation detector (FID), or a mass spectrometric detector (MS); however, derivatisation prior to GC analysis makes the estimation of impurities difficult. LC-MS/MS was found to be unsuitable for quantifying levels of impurities. It can be concluded that high-purity (>97%) B-trichothecene standards were successfully processed and fully characterised for the first time.Dedicated to the memory of Wilhelm Fresenius 相似文献
19.
A. Menditto S. Palleschi A. Minoprio B. Rossi A. Calibotti F. Chiodo M. Patriarca 《Microchemical Journal》2000,67(1-3)
The presence of chemicals in the environment is a matter of concern in that it poses potential health risks. At present, exposure to toxic chemicals and their biological and biochemical effects can be better estimated by biological monitoring, through the systematic collection of specimens from potentially exposed humans. Biological monitoring of human exposure to environmental pollutants is hampered by the difficulty to assess data reliability. As a consequence, the validity of biological monitoring should depend on the strict implementation of a quality assurance (QA) program, which includes a series of procedures aiming to ensure that laboratory results meet defined standards of quality and are reliable. For the validation and monitoring of methods’ performance, to ensure the trueness of measurements and to warrant the traceability to international standards, reference materials (RMs) and certified reference materials should be used. Internal quality control and external quality assessment (EQA) are part of overall QA and are carried out to verify that analytical errors are compatible with the specific requirements or needs of the user. In particular EQA schemes (EQAS) allow to test independently the analytical performance of participating laboratories. In the last decades, increasing concern has been raised by urban air pollution; lead and benzene, two gasoline components released by motor vehicle exhausts, are known to be toxic to humans. For biological monitoring of lead exposure of the general population, screening campaigns, utilizing lead in blood as a biomarker, have been carried out since the 1970s. Strict strategies were adopted to ensure data comparability, including the preparation of RMs, the organization of EQAS and the cross-exchange and analysis of blood samples between laboratories. Biological monitoring of benzene exposure could be carried out by means of various biomarkers such as benzene in blood and benzene, trans,trans-muconic acid (t,t-MA) and S-phenylmercapturic acid (S-PMA) in urine. At present, few RMs and EQAS are available for these biomarkers. A pilot EQAS for t,t-MA in urine, adopted to assess the reliability of data regarding benzene exposure, has been organized and carried out between 1996 and 1997 in Italy. From the accrued experience, it clearly emerges the importance of strategies designed to guarantee the quality of biological monitoring data. The use of RMs and the participation in EQAS are highly recommended in order to improve the global performance of methods and laboratories involved in biological monitoring. 相似文献