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1.
P. Davies 《Accreditation and quality assurance》1996,1(6):240-246
Laboratory accreditation is becoming increasingly accepted around the world as a means of identifying technically competent
laboratories. It is also being used as a mechanism for the acceptance of test data both nationally and internationally. The
concept and mechanisms of accreditation have been developed over the past 50 years. The first national laboratory accreditation
system appeared in Australia in 1947. This organisation, known as the National Association of Testing Authorities (NATA),
has since taken a leading role in developing accreditation practices that are now used world-wide in evaluating testing, measurement
and calibration laboratories. This paper examines the development of the world's first and largest laboratory accreditation
system, and looks at the difficulties and triumphs in gaining acceptance and recognition by government and industry of the
benefits of laboratory accreditation.
Received: 24 June 1996 Accepted: 25 June 1996 相似文献
2.
A new, simple, and rapid capillary electrophoresis (CE) method employing hexadimethrine bromide (HDB) as electroosmotic flow
(EOF) modifier was developed for the identification and quantitative determination of two pharmaceutically active constituents—gallic
acid (GA) and salidroside (S)—in extracts of Rhodiola root and its medicinal preparation. The optimum separation was achieved
at pH 11.00 with the use of 10 mM borate buffer containing 0.001% (w/v) of HDB. The applied voltage was ∼15 kV and the capillary
temperature was kept constant at 25°C. m-Phthalic acid was used as an internal standard for quantification. The calibration
dependences exhibited good linearity for the ratios of the concentrations of standard samples and internal standard and the
ratios of the peak area of samples and internal standard over the concentration range from 24 to 1200 μg/mL for GA and 2.4
to 72 μg/mL for S. The correlation coefficients were 0.9999 and 0.9997, and the detection limits of the CE method corresponding
to a signal-to-noise ratio of three were 6 and 2 μg/mL for GA and S, respectively. The relative standard deviations of the
relative migration time and the relative peak area of samples were 0.5 and 4.0% for GA and 1.9 and 5.3% for S. The effects
of buffer pH and the concentration of HDB on the resolution were studied systematically. The contents of these two active
compounds in Rhodiola root and its preparation were successfully determined over 6 min with satisfactory repeatability and
recovery.
The text was submitted by the authors in English. 相似文献
3.
A. V. Ivanov B. P. Luzyanin A. A. Moskovtsev A. S. Rotkina A. A. Kubatiev 《Journal of Analytical Chemistry》2011,66(3):317-321
The advantages and potencies of direct methods for the quantification of homocysteine based on mass spectrometry detection
(HPLC-MS and CE-MS) are considered; these significantly simplify sample preparation and exclude derivatization with expensive
derivatizing reagents. An approach is developed for the direct determination of total homocysteine in blood plasma in an analytical
system that combines capillary electrophoresis with electrospray ionization. The internal standard is glycyl-asparagine; the
duration of separation is 25 min. The sample is preconcentrated tenfold prior to the determination. The sample pretreatment
also includes the precipitation of proteins with methanol and the reduction of amino thiols with dithiothreitol or mercaptoethanol.
The recovery values make 87–112%. 相似文献
4.
A set of 25 monoprotic bases is proposed as internal standards for pK(a) determination by capillary electrophoresis. The pK(a) of the bases is determined and compared with available literature data. The capillary electrophoresis internal standard method offers numerous advantages over other typical methods for pK(a) determination, especially of analysis time and buffer preparation. However, it requires disposing of appropriate standards with reference pK(a) value. The set of bases established in this work together with the set of acids previously established provide a reference set of compounds with well-determined acidity constants that facilitate the process of selecting appropriate internal standards for fast pK(a) determination by capillary electrophoresis in high throughput screening of pharmaceutical drugs. In addition, the performance of the method when acidic internal standards are used for the determination of acidity constants of basic internal standards has also been tested. Although higher errors may be expected in this case, good agreement is observed between determined and literature values. These results indicate that in most cases structural similarity between the analyte and the internal standard might not be an essential requirement in the internal standard method. 相似文献
5.
Optimization of affinity capillary electrophoresis for routine investigations of protein–metal ion interactions
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Hassan A. Alhazmi Sami El Deeb Markus Nachbar Sabine Redweik Hassan M. Albishri Deia Abd El‐Hady Hermann Wätzig 《Journal of separation science》2015,38(20):3629-3637
To facilitate the implementation of affinity capillary electrophoresis into routine binding screening studies of proteins with metal ions, method acceleration, transfer and precision improvement were investigated. Affinity capillary electrophoresis was accelerated by using shorter capillaries, employing lower sample concentrations and smaller injection volumes. Intra‐ and inter‐instrument method transfers were investigated considering the temperature setting of the capillary cooling system. For intra‐instrument method transfer, similar results were obtained when transferring a method from a long (62 cm) to a short (31 cm) capillary. The analysis time was reduced from 9 to 4 min. In case of inter‐instrument method transfer, interaction results showed small variation on the capillary electrophoresis instrument with inefficient capillary cooling system. Binding measurement precision was enhanced by slightly pushing the sample above the beginning of the capillary. Changing the buffer vials after each 30 runs and employing extra flushing after each 60 subsequent runs further enhanced the precision. The use of 0.1 molar ethylenediaminetetraacetic acid in the rinsing solution successfully desorbs the remaining metal ions from the capillary wall. Excellent precision for apparent mobility ratio measurements was achieved for different protein–metal ion interactions (relative standard deviation of 0.16–0.89%, 15 series, 12 runs for each). 相似文献
6.
A direct, completely automated calibration procedure in capillary electrophoresis (CE) is presented. The manual calibration operations involved in analytical methods, such as external calibration, standard addition, and internal standard, were accomplished with a continuous flow system (CFS) coupled to commercial capillary electrophoresis equipment via a programmable arm. The system was managed by the proper CE microprocessor and allowed automatic calibration and direct quantification of the analytes in the sample without any manual pretreatment, therefore avoiding or minimizing manually associated errors. The whole system including peristaltic pumps and the programmable arm was connected via an electronic interface and completely controlled by a computer using a program written in GW-BASIC. The potential of this new CFS-CE arrangement was assessed by applying it to samples containing selected compounds. 相似文献
7.
G. Price 《Accreditation and quality assurance》1996,1(4):150-159
Economic and technological change, regional and international trade and the globalisation of industry have led to intense
pressures for improvements to analytical quality, reliability and comparability. Of central importance are national traceability
structures connecting chemical measurements in the field with internationally accepted measurement units and their practical
realisations. Australia has a developed physical and engineering measurement system, a legislative framework for analytical
traceability and, in the National Association of Testing Authorities, a recognised laboratory accreditation system. The need
has been identified to develop the technical capability to perform matrix-independent reference measurements for the certification
of traceable reference materials, useable as practical analytical etalons to establish metrological control systems in field
measurements for amounts of substance. Recently, a unique collaborative consortium has proposed a National Analytical Reference
Laboratory (NARL). The NARL is designed to be a metrological mass spectrometry facility for the transference of measurement
units to more widely useable chemical measurement standards and reference materials.
Received: 10 October 1995 Accepted: 26 October 1995 相似文献
8.
Lourdes Arce Angel Ríos M. Valcárcel 《Fresenius' Journal of Analytical Chemistry》1998,360(6):697-701
An integrated continuous flow-capillary electrophoresis for the determination of soluble anions in soil samples is presented.
A filtration probe coupled with the flow system, which is located before the capillary electrophoresis instrument, was designed
to simplify sample pretreatment and to perform clean-up of aqueous soil suspensions. Only the manual weighing of the samples
is needed. The extraction process for soil samples was optimized. The clear filtrate containing the soluble anions from soil
was then passed to the capillary electrophoresis equipment by a home-made programmable arm. Chloride, sulfate, nitrite and
nitrate were determined in soil samples at μg g–1 level and the results compared to manual reference methods. The precision expressed as relative standard deviation was in
the range of ± 1.6 to ± 2.5% for the set of analytes determined. The procedure is up to 4 times faster than the competitive
manual methods.
Received: 29 July 1997 / Revised: 10 September 1997 / Accepted: 13 September 1997 相似文献
9.
In-house pH reference materials (IHRMs) traceable to the corresponding NIST pH standards have been developed. Characterization
of the IHRMs was based on a comparative approach implying transmission of measurement information from the corresponding standard
to the IHRM by simultaneous pH measurements in solutions of both the IHRM and the standard under the same conditions. While
the measurements were performed, a statistically detectable temporal drift of the measurement system took place. This did
not hinder extraction of the necessary measurement information by way of the comparative approach applied.
Correspondence: The National Physical Laboratory of Israel (INPL), Givat Ram, Jerusalem 91904, Israel. e-mail: ilya_kus@netvision.net.il
Received August 20, 2002; accepted November 8, 2002 相似文献
10.
High speed single nucleotide polymorphism typing of a hereditary haemochromatosis mutation with capillary array electrophoresis microplates 总被引:2,自引:0,他引:2
A single nucleotide polymorphism (SNP) typing assay is developed and evaluated on a microfabricated capillary array electrophoresis system. Using fluorescently labeled allele-specific primers, the S65C (193A-->T) substitution associated with hereditary haemochromatosis in the HFE gene is genotyped. The covalently labeled polymerase chain reaction (PCR) products are separated on a microfabricated radial capillary array electrophoresis microplate using nondenaturing gel media in under two minutes. Detection is accomplished with a laser-excited rotary confocal scanner. The Rox-labeled A-allele specific amplicon (211 bp) is differentiated from the R110-labeled T-allele specific amplicon (201 bp) by both size and color. This study demonstrates the feasibility of using allele-specific PCR with covalently labeled primers for high speed fluorescent SNP typing on microfabricated radial capillary array electrophoresis microplates. 相似文献
11.
Gene analysis of multiple oral bacteria by the polymerase chain reaction coupled with capillary polymer electrophoresis
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Chenchen Liu Yoshinori Yamaguchi Shinichi Sekine Yi Ni Zhenqing Li Xifang Zhu Xiaoming Dou 《Journal of separation science》2016,39(5):986-992
Capillary polymer electrophoresis is identified as a promising technology for the analysis of DNA from bacteria, virus and cell samples. In this paper, we propose an innovative capillary polymer electrophoresis protocol for the quantification of polymerase chain reaction products. The internal standard method was modified and applied to capillary polymer electrophoresis. The precision of our modified internal standard protocol was evaluated by measuring the relative standard deviation of intermediate capillary polymer electrophoresis experiments. Results showed that the relative standard deviation was reduced from 12.4–15.1 to 0.6–2.3%. Linear regression tests were also implemented to validate our protocol. The modified internal standard method showed good linearity and robust properties. Finally, the ease of our method was illustrated by analyzing a real clinical oral sample using a one‐run capillary polymer electrophoresis experiment. 相似文献
12.
S. Jaenicke 《Catalysis Surveys from Asia》2005,9(3):173-185
The following report gives an overview on work done in the Catalysis Laboratory of the Department of Chemistry, National University
of Singapore over the last 15 years (1989–2004). Much of this work can be described as “characterization of catalytically
active surfaces through test reactions”. The methods, systems studied and the reactions that we evaluated will be described.
The review will mostly concentrate on work from the authors’ laboratory, but other relevant work will also be cited. 相似文献
13.
Indirect fluorescence detection of phenolic compounds by capillary electrophoresis on a glass device
Martin Arundell Peter D. Whalley A. Manz 《Analytical and bioanalytical chemistry》2000,367(8):686-691
A micromachined capillary electrophoresis system has been fabricated on a glass device for the separation and indirect fluorescence
detection of phenols. Using this device two phenols viz., 2,4-dichlorophenol and pentachlorophenol, were separated within 12 s compared to under 19 min on a conventional capillary
electrophoresis system using direct ultraviolet detection. The precision of the glass device ranged from 12.7%–16.7% compared
to 0.42%–4.9% for the conventional system. Both systems showed good linearity in the concentration range of 0.8– 6.38 mM for
the glass device and 5–130 μM for the conventional system. The relationship between temperature and high voltage with baseline
drift was also investigated. These results provide a foundation for the development of a miniaturised chemical analysis system
for the on-line analysis of phenols in water.
Received: 24 January 2000 / Revised: 27 March 2000 / Accepted: 29 March 2000 相似文献
14.
Determination of chloramphenicol in biological matrices by solid‐phase membrane micro‐tip extraction and capillary electrophoresis
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Solid‐phase membrane micro‐tip extraction (SPMMTE) and capillary electrophoresis (CE) methods were developed and validated for analysis of chloramphenicol in human plasma and urine samples. Iron composite nanoparticles were prepared using green technology. CE was carried out using a silica capillary (60 cm × 50 μm i.d.), phosphate buffer (50 mm , 8.0 pH)–acetonitrile (95:5, v/v) as the background electrolyte, 10 kV voltage, 280 nm detection, 20 s injection time and 27 ± 1°C temperature. Frusemide was used as an internal standard. The values of migration time, electrophoretic mobility, electrophoretic velocity and theoretical plates of chloramphenicol were 12.254 min, 4.44 × 10, 7.41 × 10 and 11,227. The limits of detection and quantitation of chloramphenicol were 0.1 and 1.0 μg/mL. Recovery of chloramphenicol in the standard solution was 95%. Solid‐phase membrane micro‐tip extraction and capillary electrophoresis methods may be used to analyze chloramphenicol in human plasma and urine samples of any patient. 相似文献
15.
The trypsin digest of a mixture of two proteins, namely cytochrome c and myoglobin, was first separated in the first dimension by high-performance liquid chromatography (HPLC). Fractions from the HPLC were collected every 30s with the aid of a fraction collector into a 96-well microtiter plate. After concentration, all the collected fractions were analyzed simultaneaosly in the second dimension by a 96-array capillary electrophoresis system. The labeled peptides were detected by laser-induced fluorescence. An internal standard, allura red, was added to all the fractions, prior to capillary electrophoretic analysis. The internal standard serves two functions, migration time correction and signal intensity correction. The data are presented in two different formats, as an electropherogram of all the fractions and in a two-dimensional (2-D) format. The 2-D plot of the data shows the density of each spot, which corresponds to the concentration of the migrating peptides. The total experimental time for the HPLC and capillary electrophoretic analyses ist less than 1 h, which ist much faster than using 2-D slab-gel electrophoresis or single-capillary capillary electrophoresis. 相似文献
16.
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. 相似文献
17.
Yeung SH Seo TS Crouse CA Greenspoon SA Chiesl TN Ban JD Mathies RA 《Electrophoresis》2008,29(11):2251-2259
A fluorescence energy transfer (ET) dye-labeled STR typing system (ET 16-plex) is developed for the markers used in the commercial STR typing kit PowerPlex 16, and its performance assessed using a 96-lane microfabricated capillary array electrophoresis (muCAE) system. The ET 16-plex amplicons displayed 1.6-9-fold higher fluorescence intensities compared to those produced using the single-dye (SD)-labeled multiplex kits. The ET multiplex delivered full STR profiles from 62.5 pg of DNA; half the input required for the SD kits while maintaining a similar heterozygote allele balance. This increased sensitivity should improve typing of poor-quality DNA samples by making minor or imbalanced alleles more readily detectable at the low copy number (LCN) threshold. The ET 16-plex also generated complete profiles with only 28 PCR cycles; this capability should improve LCN typing by reducing the amplification time and drop-in allele incidence. To confirm the practical advantages of ET-labeled primers, six previously problematic casework samples were tested and only the ET 16-plex kit was able to capture additional allele data. The successful development and demonstration of ET primers for higher sensitivity STR typing offers a simple solution to improving current commercial multiplex typing capability. The superior spectral properties and universal compatibility with any primer sequence provided by ET cassettes will make future multiplex construction more facile and straightforward. The pairing of ET cassette technology with the muCAE system illustrates not only an enhanced STR typing platform, but a significant step toward a higher-efficiency forensic laboratory enabled by better chemistry and microfluidics. 相似文献
18.
J. Escoriaza M. C. Dios-Viéitez I. F. Trocóniz M. J. Renedo D. Fos 《Chromatographia》1997,44(3-4):169-171
Summary A sensitive method was developed for the determination of temazepam in plasma using capillary gas chromatography. After the
extraction into dichloromethane-pentane (1∶1), temazepam was quantitated as its O-trimethylsilyl derivative on a capillary
column with a63Ni electron capture detector using prazepam as internal standard. The detector response was found to be linear in the concentration
range 0.031 to 8 μg mL−1. The detection limit was about 3.5 ng mL−1. The intraday and inter-day coefficients of variation were below 9%. The method was used to determine the pharmacokinetic
profile of temazepam in rats after intravenous administration. 相似文献
19.
Mary M. Kimberly Gary L. Myers Randie R. Little 《Accreditation and quality assurance》2004,9(1-2):18-23
The Centers for Disease Control and Prevention, or CDC, has a long history of providing traceability in clinical laboratory medicine. Early work was to develop reference methods for important clinical analytes. When the National Cholesterol Education Program issued recommendations for physicians and clinical laboratories for measurement of lipids and lipoproteins, CDC formed the Cholesterol Reference Method Laboratory Network (CRMLN) to provide manufacturers with access to the accuracy bases. The CRMLN assists manufacturers with calibration of diagnostic products to ensure traceability to higher-order technology. A certification program for manufacturers assures the clinical laboratory community that these products are accurate and precise. The CRMLN model for traceability has been applied to other networks, notably the National Glycohemoglobin Standardization Program.Presented at the CCQM Workshop on Traceability, 16–17 April 2002 at the BIPM, Sèvres, France 相似文献
20.
M. Marouli J. Dean N. M. Spyrou 《Journal of Radioanalytical and Nuclear Chemistry》2008,277(1):261-264
A UK primary standard and monitor calibration service for positron emitting radionuclides in gases are needed by users of
cyclotron facilities to enable them to calibrate radioactivity-in-air monitors and thus ensure the accuracy and traceability
of measurements of any airborne radioactivity releases arising from the production of these radionuclides. A system of gas
flow proportional counters, already established at the National Physical Laboratory (NPL) for the standardization of β−-emitting gases, was used as the basis of the primary standard. This paper focuses on initial problems encountered in the
use of the system for measuring positron emitters. 相似文献