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高占科于惠莉袁玲玲程绍华 《化学分析计量》2021,30(10):78-84
为评价海洋检验检测机构海水盐度检测能力,国家海洋标准计量中心设计并实施了2020年度海水盐度能力验证计划,制备能力验证样品并开展均匀性检验。本次能力验证采用双样品以随机组合形式发放,利用迭代算法A对62家实验室提交的能力验证数据进行统计分析处理,合理确定指定值及其不确定度,将能力验证数据转化为能力统计量,根据Z比分数评定各参加实验室能力验证结果。结果显示,双样品全部“满意”的实验室有52家,占85.5%,有3家实验室能力验证结果“不满意”,6家实验室能力验证结果“有问题”。“不满意”和“有问题”的实验室共占14.5%。本次能力验证数据的频率分布接近正态分布,通过开展双样品联合置信概率分析和仪器类型统计分析,与往年能力验证结果“满意率”进行比较,绝大多数实验室海水盐度检测能力良好,个别实验室仍需加强海水盐度检测能力建设和内部质量控制。 相似文献
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舒晓莲陈鹰李杰 《理化检验(化学分册)》2018,(11):1281-1286
为全面、客观、科学地了解和评价上海市有关实验室对水产品中磺胺类药物(SAs)残留量的检测能力,计划并实施了水产品中SAs残留量检测能力的验证。参加本项目的实验室达17家,通过养殖给药方式制备了阳性鱼肉样品。采用单因子方差分析法和平均值一致性检验法对样品进行均匀性和稳定性检验。对各参加实验室上报结果进行稳健统计分析,采用Z比分数评定各参加实验室的结果。17家资质实验室中获得满意结果的有15家,水产品中磺胺类药物残留检测能力总体较好。对数据结果分析表明:样品前处理和标准物质的选用是最容易引入误差的环节。 相似文献
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面对日趋完善的食品接触材料卫生标准体系,为掌握高锰酸钾消耗量测定的技术要求,做好相应合规性判定,充分发挥能力验证对检验检测机构技术能力监督和质量提升的作用,该文进行了食品接触用塑料材料及制品中高锰酸钾消耗量的测定能力验证。通过定制棕色塑料食品包装瓶作为相关能力验证样品,依据相关标准要求进行均匀性、稳定性评价,对回收结果采用稳健统计技术算法A确定指定值和能力评定标准差,并对可能产生不满意结果的影响因素进行了分析。192家参与该项能力验证的实验室中有179家结果为满意,满意率为93.2%;12家实验室结果为不满意,占6.3%;1家实验室结果为可疑,占0.5%。总体结果较好,个别实验室出现的不合格结果可通过本次能力验证分析查找原因,达到提高实验室相应检测能力的目的。 相似文献
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实施茶叶中甲氰菊酯测定能力验证计划,对不同的结果评价方式进行对比。制备含甲氰菊酯的茶叶样品,经均匀性和稳定性考察合格后用于能力验证。以专家实验室结果平均值作为指定值,由再现性标准差和重复性标准差求计算出能力评定标准差,评价参加者能力。用稳健算法、经验模型法确定统计评价量,与本法测定结果进行比对。结果显示,5家专家实验室提供了呈现正态分布且等精度的结果,评价结果的满意率为88.7%。与其它评定方式相比,本法给出的满意结果区间较为严格,能够反映检验机构应达到的检测水平。 相似文献
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研制了海藻糖国家标准样品。以食品级海藻糖粗品为原料,纯化制备海藻糖,采用红外光谱(IR)、质谱和核磁共振谱(NMR)以及单晶衍射等方法进行结构确证。样品分装成400瓶后,采用离子色谱法进行均匀性、稳定性检验和定值分析。从样品中随机抽取15瓶进行均匀性检验,经F检验表明,在95%的置信区间范围内,样品均匀性良好。在40℃下,经过24个月稳定性考察,结果表明样品稳定性良好。标准样品经国内8家具有分析资质的实验室进行协同定值,并评定了定值结果的不确定度,海藻糖标准样品定值结果为99.72%,扩展不确定度为0.26%(k=1.96)。该标准样品达到国家标准样品的技术要求,可用于有关海藻糖的方法校正和质量控制。 相似文献
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研制乳粉中硝酸盐、亚硝酸盐分析标准样品。获得原料并确认后,对原料添加目标物,混匀,喷雾干燥,分装,包装制成标准样品。对样品进行均匀性、稳定性检验,通过多家实验室联合定值的方式对样品进行定值,从而获得标准值及其不确定度。样品中硝酸盐、亚硝酸盐均匀性检测数据经F检验在95%置信水平时单元件不具有统计显著性,表明样品是均匀的;样品稳定性检测数据经t检验,表明样品在-20℃保存条件下18个月内量值稳定;对8家有能力的实验室联合定值数据统计分析得到样品中硝酸盐标准值为22.4 mg/kg,不确定度为0.95 mg/kg(k=2);亚硝酸盐标准值为23.0 mg/kg,不确定度为0.93 mg/kg(k=2)。样品均匀性、稳定性、赋值和不确定度评估等均符合有证标准样品的要求,能够满足预期用途。 相似文献
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Lafargue ME Feinberg MH Daudin JJ Rutledge DN 《Analytical and bioanalytical chemistry》2003,375(4):496-504
Samples distributed in proficiency testing schemes (PTS) need to be homogeneous in order to be sure that if a laboratory has a result different from the other laboratories, its error can be attributed to its analysis method and not to its sample. This control must be done according to the ISO 13528 draft standard before sending the samples to the laboratories. It can be done by determining homogeneity targets by sub-contracting to accredited laboratories using reference methods, but this engenders logistic and financial problems. That is why a homogeneity check using Near Infrared Spectroscopy (NIR) has been developed for agricultural and food industries samples prepared for PTS at Bipea (Bureau Interprofessionnel d'Etudes Analytiques). To evaluate the homogeneity among samples, this procedure involves a comparison of NIR spectra, the determination of global homogeneity criteria and the use of control charts. The method of control developed and carried out at Bipea allows the rapid and easy monitoring of the performance of the sample preparation. 相似文献
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Ian Robert Juniper 《Accreditation and quality assurance》1999,4(8):336-341
Proficiency testing is a means of assessing the ability of laboratories to competently perform specific tests and/or measurements.
It supplements a laboratory's own internal quality control procedure by providing an additional external audit of their testing
capability and provides laboratories with a sound basis for continuous improvement. It is also a means towards achieving comparability
of measurement between laboratories. Participation is one of the few ways in which a laboratory can compare its performance
with that of other laboratories. Good performance in proficiency testing schemes provides independent evidence and hence reassurance
to the laboratory and its clients that its procedures, test methods and other laboratory operations are under control. For
test results to have any credibility, they must be traceable to a standard of measurement, preferably in terms of SI units,
and must be accompanied by a statement of uncertainty. Analytical chemists are coming to realise that this is just as true
in their field as it is for physical measurements, and applies equally to proficiency testing results and laboratory test
reports. Recent approaches toward ensuring the quality and comparability of proficiency testing schemes and the means of evaluating
proficiency test results are described. These have led to the drafting of guidelines and subsequently to the development of
international requirements for the competence of scheme providers.
Received: 2 January 1999 · Accepted: 7 April 1999 相似文献
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Siu Kay Wong 《Accreditation and quality assurance》2005,10(8):409-414
Proficiency testing (PT) is an essential tool used by laboratory accreditation bodies to assess the competency of laboratories.
Because of limited resources of PT providers or for other reasons, the assigned reference value used in the calculation of
z-score values has usually been derived from some sort of consensus value obtained by central tendency estimators such as the
arithmetic mean or robust mean. However, if the assigned reference value deviates significantly from the ‘true value’ of the
analyte in the test material, laboratories’ performance will be evaluated incorrectly. This paper evaluates the use of consensus
values in proficiency testing programmes using the Monte Carlo simulation technique. The results indicated that the deviation
of the assigned value from the true value could be as large as 40%, depending on the parameters of the proficiency testing
programmes under investigation such as sample homogeneity, number of participant laboratories, concentration level, method
precision and laboratory bias. To study how these parameters affect the degree of discrepancy between the consensus value
and the true value, a fractional factorial design was also applied. The findings indicate that the number of participating
laboratories and the distribution of laboratory bias were the prime two factors affecting the deviation of the consensus value
from the true value. 相似文献
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Mushroom reference material has been prepared and characterized for use in proficiency test exercises within the frame of
an IAEA Interregional Technical Cooperation Project. Laboratories from 14 countries provided results for homogeneity testing
and the assignment of property values. The contents of 11 elements have been assigned. The material was used for conducting
a proficiency test in Poland and the results obtained by Polish laboratories are presented and discussed. 相似文献
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M. Grimaldi M. Mancin R. Trevisan R. Mioni 《Accreditation and quality assurance》2009,14(8-9):503-505
In 1999 the Food Microbiology laboratory of the Istituto Zooprofilattico Sperimentale delle Venezie (IZSVe) started an interlaboratory comparison program for food microbiological tests, known as “Aqua, interlaboratory comparisons for quality assurance”. Aqua produces the test samples, applies statistical methods to estimate homogeneity and stability, processes and evaluates the results. The proficiency testing results allow to evaluate the performance of the laboratories, to identify possible differences and non-conformity, to demonstrate the competence and the quality of results, in order to take suitable corrective and/or preventive action after the individuation of the causes. Moreover, elaborating the results of several proficiency testing by using the control chart method, it is possible to evaluate the trend of the laboratory and to verify that the results are in statistical quality control. 相似文献
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水平测试样品的均匀性保证 总被引:1,自引:0,他引:1
为确保水平测试样品的均匀性,文中阐述了水平测试、样品制备、均匀性检验的取样数量、取样方式、最小取样量、测量方法和统计方法,重点介绍了均匀性检验的统计方法。 相似文献
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Daniel William Tholen 《Accreditation and quality assurance》1998,3(9):362-366
There are three stages to evaluating a laboratory's results in an interlaboratory proficiency test: establishing the correct
result for the test item, determining an evaluation statistic for the particular result, and establishing an acceptable range.
There are a wide variety of procedures for accomplishing these three stages and a correspondingly wide variety of statistical
techniques in use. Currently in North America the largest number of laboratory proficiency test programs are in the clinical
laboratory field, followed by programs for environmental laboratories that test drinking water and waste water. Proficiency
testing in both of these fields is under the jurisdiction of the federal government and other regulatory and accreditation
agencies. Many of the statistical procedures are specified in the regulations, to assure comparability of different programs
and a fair evaluation of performance. In this article statistical procedures recommended in International Organization for
Standardization Guide 43, Part 1, are discussed and compared with current practices in North America.
Received: 22 April 1998 · Accepted: 12 May 1998 相似文献
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J. L. Parr 《Accreditation and quality assurance》1998,3(9):376-378
There is currently no national program for recognition of United States environmental laboratories. This situation should
change sometime in 1998 as environmental testing laboratories should be able to apply for accreditation in the United States
via a system developed by the National Environmental Laboratory Accreditation Conference (NELAC). NELAC is an organization
whose purpose is to establish performance standards for accrediting environmental laboratories. Laboratories to be accredited
will be required to demonstrate qualifications of testing personnel, pass on-site inspections, perform satisfactorily on proficiency
test samples, and meet specified quality assurance standards. 相似文献
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D. W. Seccombe 《Accreditation and quality assurance》2002,7(8-9):363-364
The Internet provides laboratory professionals with a unique opportunity to come together as a network and to develop an integrated
system for monitoring the quality of testing in their laboratories on a real-time basis. Once established this network could
provide a quality and standards promoting infrastructure for catalyzing the standardization process. Through a collaborative
sharing of information on performance and through the use of a common database with harmonized test materials, proficiency
testing providers can play a pivotal role in developing such a system. The challenge is now up to us. 相似文献