基于迭代算法A的海水盐度能力验证结果分析

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。     

铁矿石检测能力验证结果分析

为评价实验室对铁矿石的测试能力和技术水平,青岛海关技术中心于2019年组织实施了铁矿石检测的能力验证计划。该能力验证有中国和澳大利亚的52家实验室参加,主要包括海关系统、矿山公司、第三方检验公司及地质行业。能力验证项目为全铁、二氧化硅、三氧化二铝、磷、硫的检测能力,对各参加实验室提交的检测数据进行稳健统计分析。该次能力验证共收回检测结果218个;其中不满意结果3个,占总数的1.4%;异常结果9个,占总数的7.6%;满意结果206个,占总数的91%。与2018年能力验证结果相比,参加实验室数量及全铁、二氧化硅、三氧化二铝、磷、硫5个项目检测结果的满意率均有所提高。表明绝大多数参试实验室可以准确检测铁矿石中的全铁、二氧化硅、三氧化二铝、磷、硫。     

超高效液相色谱/静电场轨道阱高分辨质谱法同时测定塑料食品接触材料中光稳定剂和抗氧化剂的特定迁移量

建立了超高效液相色谱/静电场轨道阱高分辨质谱同时测定塑料食品接触材料中多种光稳定剂和抗氧化剂特定迁移量的方法。采用30 g/L乙酸、体积分数分别为10%、20%、50%的乙醇和油类模拟物(异辛烷)这5种食品模拟物对塑料食品接触材料进行处理,对处理液进行超高效液相色谱/静电场轨道阱高分辨质谱分析,外标法定量。该方法测定的40种目标化合物在相应的范围内均具有良好的线性关系,相关系数均大于0.998,定量限为0.01~1.00μg/L。考察了上述5种食品模拟物中光稳定剂和抗氧化剂的特定迁移量,平均加标回收率为81.46%~94.53%,相对标准偏差为3.25%~9.99%。应用该方法对市售塑料食品接触材料进行了测定,结果在部分样品中检出了不同含量的光稳定剂和抗氧化剂。该方法灵敏度高,定量限低,满足塑料食品接触材料中光稳定剂和抗氧化剂特定迁移量的检测要求。     

塑料食品接触材料样品前处理与检测技术研究进展

塑料食品接触材料是食品接触材料类别中最常见的一种材料,其本身可能含有的潜在化学危害物质在与食品接触过程中发生吸收、溶解、扩散等迁移行为,进而造成食品污染,危害食品质量安全。采用适宜的样品前处理和检测技术对迁移物进行鉴别分析是塑料食品接触材料安全所面临的巨大挑战。该文就塑料食品接触材料的样品前处理技术和仪器分析技术进行了综述,并展望了其发展趋势和应用前景,旨在为从事塑料食品接触材料质量安全研究和检测的技术人员提供技术参考。     

玩具油漆涂层中有机锡检测能力验证样品研制及应用分析

制备了用于可迁移有机锡检测能力验证的玩具油漆涂层样品,并开展了相关测定能力验证计划,采用迭代法、四分位法和敏感分析法3种不同统计方法对23家实验室数据进行统计分析,并对不满意结果的原因进行了分析。结果表明所研制样品的均匀性和稳定性良好,能满足能力验证要求。不同统计方法对实验室能力评定结果存在差异,但指定值差异很小,而能力评定标准差差异较大,运用卡方检验能选择出更合理的统计方法。     

水中易释放氰化物能力验证样品的研制及应用

根据国家地表水环境质量监测网监测任务要求和环境监测的实际需要,制备了水中易释放氰化物能力验证样品。通过均匀性、稳定性检验以及量值一致性评价,研制的样品均匀性良好,在3℃~6℃冷藏避光保存条件下1年内稳定,样品配制值与多家实验室协作测定结果一致。探讨了样品在能力验证活动中的应用,共有来自全国11个省的32家实验室参加了水中易释放氰化物的能力验证计划,实验室满意率在80%以上,实验室结果出现有问题或不满意主要是由于样品前处理以及检测过程质量控制不当导致的。经检测及实验室反馈的数据验证,该能力验证样品能够应用于能力验证活动。     

迭代稳健统计法用于金矿石中银含量测定的实验室间比对

采用迭代稳健统计法对实验室间金矿石中银含量的测定进行比对。介绍了金矿石中银含量测定实验室间比对计划的样品均匀性和稳定性检验、以及基于迭代稳健统计法的结果分析等实施过程。统计结果表明,样品具有良好的均匀性和稳定性,符合实验室比对的基本要求。实验室间比对结果表明,在参加的21家实验室中获得满意结果的实验室有20家,占反馈总数的95.2%,1家实验室结果可疑,占反馈总数的4.8%。大多数实验室具备准确测定金矿石中银含量的能力。     

纺织品中pH值的测定能力验证

为了了解国内纺织品检测机构对纺织品中pH值测定领域的整体水平,识别和掌握实验室存在的差异,加强纺织品检测机构的实验室能力建设,中国国家认证认可监督管理委员会(CNCA)组织了纺织品中pH值的测定能力验证活动,有16个省、市、直辖市的69个实验室参加,测试结果满意的实验室占78.26%.     

食品接触塑料材料中有害重金属迁移量测定方法综述

塑料在食品接触材料中占有重要地位,通过介绍食品接触塑料材料中重金属危害及来源,总结食品接触塑料材料中有害重金属安全限量,并对目前食品接触塑料材料中有害重金属的迁移测定方法进行综述。开发食品接触材料快速检测方法是今后研究的方向。     

利用能力验证结果评价参加实验室的整体检测能力

能力验证是利用实验室间比对确定实验室检测能力的活动,其评价结果多用于评估单个实验室的检测能力。行业监管部门期望掌握实验室整体能力和检测方法的相关信息,为分析参加实验室的整体检测能力和不同测试方法的差异,分析了3年航空煤油检测能力验证结果,采用满意结果百分比、|Z|值平均值随参加能力验证次数的变动情况,证实了能力验证对整体检测能力的改进作用;利用异方差t检验,比较不同测试方法结果的一致性和精密度差异;通过比较能力验证评价标准差和检测标准的精密度要求,评价参加实验室整体检测能力是否符合检测标准要求。研究表明,能力验证数据能够用于定量分析参加实验室的整体检测能力,为行业实验室监管和检测方法间比对提供依据。     

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.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.