实验室检测质量控制有效性评价方法探讨

控制检测结果质量,持续保持检测活动的有效性和检测结果的准确性,是检测实验室质量管理工作的根本目的。检测实验室质量控制方法主要有:1定期使用有证标准物质(参考物质)进行监控;2参加实验室间的比对或能力验证计划;3使用相同或不同方法进行重复检测;4对存留物品进行再检测或再校准;5分析一个物品不同特性结果的相关性。就上述几种质量控制方法而言,如何确定其评价方法是实验室面对的首要问题。目前我国相关国     

有证标准物质在检测实验室的3种应用

介绍了有证标准物质在检测实验室的3种应用:仪器校准、人员考核和测量结果准确性评价。重点介绍了如何使用基体有证标准物质评价结果数据的准确性,并首次从统计学原理上证明了在实验室内使用基体有证标准物质评价结果的准确性与实验室通过参加能力验证获得能力评定作用等同。     

有证标准物质的正确使用

对于从事化学检测工作的检测实验室而言,有证标准物质(包括标准溶液,下同)是一个不可或缺的、非常重要的物质,几乎所有的检测过程均需使用标准物质。尽管许多化学检测实验室及化学检测人员非常明确地知道有证标准物质对于检测过程的重要性;但是,在实际使用有证标准物质的过程中,鲜有实验室和检测人员采用统计方法对有证标准物质的检测结果进行分析、处理。本文阐述了检测实验室应如何正确使用有证标准物质。     

内部比对试验结果的统计评价方法

正在实验室常使用标准物质或质量控制物质、测量设备的期间核查、实验室内比对等方式对试验过程进行监控。同时,在AC7101/1G:2019《NADCAP对所有材料实验室的总体要求》的附录中要求各申请专业每年度需按照一定频次完成能力验证和内部比对试验,对于一些专业还专门提出了对人员的内部比对和对设备的内部比对的频次要求。为适应中国合格评定国家认可委员会(CNAS)的"确保结果有效性"的要求、国家航空航天和国防     

浅议化学检测实验室人员管理的质量控制

正实验室质量控制贯穿于化学检测全流程,这是实验室良好运行的重要保障,为了获得准确可靠的检测结果,化学检测实验室必须加强检测过程中全环节的质量管理[1]。中国合格评定国家认可委员会(CNAS)于2018年3月发布的CNAS-CL01:2018(ISO/IEC 17025:2017)《检测和校准实验室能力认可准则》以及CNAS-CL01-G001:2018《CNASCL01检测和校准实验室能力认可准则应用要求》对检测和校准实验室的能力要求进行了明确规定,人员管理是其中一项重要内容。     

标准物质在检测实验室质量控制中的应用

【】 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。     

化学分析领域能力验证与稳健统计技术

正能力验证是认可机构评价和监视实验室持续检测能力的重要手段之一,在实验室认可活动中具有非常重要的作用,是实现和维持国际互认的技术基础。能力验证也是实验室自身实现外部质量保证的重要措施,可促进实验室发现问题并采取纠正措施,提高检测和校准能力。中国合格评定国家认可委员会(CNAS)在受理检测和校准实验室的认可申请时,能力验证的结果是其是否受理认可申请的重要     

理化实验室标准物质的管理

<正>标准物质是具有准确的特性量值、高度均匀与稳定性良好的测量标准,是量值传递的物质基础。在理化检测中,标准物质可被用于测量系统的校准、测量程序的评估、给其他物质赋值、质量控制和分析方法的评价等。这些测量都依赖于标准物质,并由标准物质将测量的结果溯源到国际单位制(SI)。因此,标准物质是实验室开展检测工作所必需的重要资源,其正确的管理和使用是实验室检测工作的一项重要基础内容,也是实验室质量管理体系的重要     

食品检测过程质量控制要素

正在食品理化检测工作中如何保证连续出具准确、可靠的检测结果,有效地控制检验活动,证明检测过程的稳定性,降低和避免检验质量问题的发生一直是食品理化检验实验室关注和研究的问题。对实验室全部质量要素的控制称为内部质量控制,实验室的检验质量受到检验人员、操作过程、仪器设备、试验试剂、检验方法、试验环境等因素的影响。实验室内部常用的质量控制方法较多,适用于化学实验室的方法有人员比对、方法比对、仪器比对、留     

质量控制图在测定土壤中4种重金属元素的应用

<正>RB/T214-2017?检验检测机构资质认定能力评价检验检测机构通用要求?中要求检验检测机构应建立和保持质量控制程序,定期参加能力验证或机构之间比对^[1].质量控制图是实验室进行质量控制最简单、有效的工具之一,通过对质量控制图中的数据点进行比对分析,在数据不符合预先判据的情况下,按照程序修正所产生的问题,以免报告不正确的后果.质量控制图是实验室进行内部质量控制最重要的方法之一,是用于监控系统误差和随机误差对控制值产生的联合效应^[2],如空白值、回收率以及曲线斜率/截距监控等.通过监控控制值的波动情况及变化趋势来检测环境是否发生异常,当检测过程中发生系统性失控或变异,质量控制图中数据点的突变可以达到及时“报警”的目的.当检测人员发现异常时立即采取纠偏及预防措施,能使检测流程恢复稳定,进而不断提高和改进现有流程的质量水平.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.