实验室管理系统结合短信平台在食品检测标准物质管理中的应用

食品检测实验室大量使用标准物质,而根据实验室认可及资质认定等文件规定,标准物质在使用管理上需要完备的记录链,数量众多的标准物质使实验室标准物质管理增加了难度。利用实验室管理系统与短信平台相结合的技术管理标准物质,构建标准物质采购、入库、验收、保存、使用等信息管理系统,使标准物质管理中物流与信息流保持同步,提高了实验室标准物质管理水平。     

国内标准物质概况及重点领域发展现状

介绍标准物质的层级分类及重点领域内标准物质的研发现状。标准物质有两种分类方法:术语层级分类和计量学层级分类,国内标准物质按照等级划分为一级、二级标准物质、标准样品和行业标准样品。介绍了标准物质生产资质和标准物质证书的要求,以及重点领域医药、金属、油品、食品、环境标准物质的发展现状。     

地质分析中标准物质的选用及注意事项

对地质分析时使用标准物质的一般原则、容易忽略的问题、贵金属标准物质的选择、过期标准物质的选择、疑难样品“标准物质室”的建立、仪器期间核查标准物质的选择进行了论述。     

环境监测分析中标准物质的选择及应用

针对分析人员对标准物质概念不清、使用不规范等问题,就环境监测领域标准物质选择和应用方法做了梳理.从标准物质的概念、区分有证和非有证标准物质的方法、标准物质的应用范围及标准物质的使用注意事项等4个方面系统地进行了梳理,重点阐述了有证标准物质和非有证标准物质的概念区别及使用时的误区,为分析人员在实际工作中出具准确数据提供理...     

煤、焦炭标准物质的稳定性考察及评价

介绍了影响煤、焦炭标准物质稳定性的因素，以实际煤、焦炭标准物质为例，考察了煤、焦炭标准物质的稳定性，介绍了评价煤、焦炭标准物质稳定性的方法，提出了保证煤、焦炭标准物质稳定性的措施。     

我国标准物质的管理及其发展

阐述了我国标准物质的分类、分级、编号及其管理。描述了标准物质的溯源体系及定值的组织系统,介绍了国际标准物质信息库。     

塑料制品中高关注物质测定方法的研究进展

综述了塑料制品中高关注物质测定方法的研究进展。介绍了邻苯二甲酸酯、有机锡、阻燃剂和全氟化合物等4类高关注物质的化合物信息,总结了气相色谱法、液相色谱法及质谱法测定塑料制品中上述高关注物质,并展望了高关注物质测定方法的发展趋势(引用文献40篇)。     

《实用地质分析标准物质手册》(第二版汉英对照)

编者收集整理了当今地质分析所用的标准物质647个,按其特征和不同应用分成6个部分介绍,即元素整体分析标准物质、超细粒度标准物质、化学物相和元素形态分析标准物质、微区原位分析标准物质、同位素及地质年代学分析标准     

《实用地质分析标准物质手册》(第二版 汉英对照)

编者收集整理了当今地质分析所用的标准物质647个,按其特征和不同应用分成6个部分介绍,即元素整体分析标准物质、超细粒度标准物质、化学物相和元素形态分析标准物质、微区原位分析标准物质、同位素及地质年代学分析标准     

《实用地质分析标准物质手册》(第二版汉英对照)

编者收集整理了当今地质分析所用的标准物质647个,按其特征和不同应用分成6个部分介绍,即元素整体分析标准物质、超细粒度标准物质、化学物相和元素形态分析标准物质、微区原位分析标准物质、同位素及地质年代学分析标准物质、有机污染物分析标准物质。为了适应不同的查找方式,手册中有4种表格提供查找(综合信息表、定值信息表、定值数据简表、特性量值索引)。     

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%.     

MISCIBILITY AND MORPHOLOGY OF THIN FILMS OF BLENDS OF POLYSTYRENE WITH BROMINATED POLYSTYRENES： EFFECTS OF VARYING THE MOLECULAR WEIGHT, BROMINATION DEGREE AND ANNEALING

Thin films of incompatible polymer blends can form a variety of structures during preparation and subsequent annealing process. For the polymer blend system consisting of polystyrene and poIy(styrene-co-p-bromo-styrene), i.e., PS/PBrxS, its compatibility could be adjusted by varying the degree of bromination and the molecular weight of both components comprised, in this paper, surface chemical compositions of the cast and the annealing films were investigated by X-ray photoelectron spectroscopy (XPS) and contact angle measurement; meanwhile, surface topographical changes are followed by atomic force microscopy (AFM). In addition, substantial attention was paid to the effect of annealing on the morphologic variations induced by phase separation and/or dewetting of the thin film. Moreover, the influences of the molecular weight, Aw, as well as the brominated degree, x%, on the sample surface are explored systematically, and the corresponding observations are explained in virtue of the Flory-Huggins theory, along with the dewetting of the polymer thin film.     

Self-Assembling Drug Formulations with Tunable Permeability and Biodegradability

This review focuses on key topics in the field of drug delivery related to the design of nanocarriers answering the biomedicine criteria, including biocompatibility, biodegradability, low toxicity, and the ability to overcome biological barriers. For these reasons, much attention is paid to the amphiphile-based carriers composed of natural building blocks, lipids, and their structural analogues and synthetic surfactants that are capable of self-assembly with the formation of a variety of supramolecular aggregates. The latter are dynamic structures that can be used as nanocontainers for hydrophobic drugs to increase their solubility and bioavailability. In this section, biodegradable cationic surfactants bearing cleavable fragments are discussed, with ester- and carbamate-containing analogs, as well as amino acid derivatives received special attention. Drug delivery through the biological barriers is a challenging task, which is highlighted by the example of transdermal method of drug administration. In this paper, nonionic surfactants are primarily discussed, including their application for the fabrication of nanocarriers, their surfactant-skin interactions, the mechanisms of modulating their permeability, and the factors controlling drug encapsulation, release, and targeted delivery. Different types of nanocarriers are covered, including niosomes, transfersomes, invasomes and chitosomes, with their morphological specificity, beneficial characteristics and limitations discussed.     

化学平衡有向图

根据化学平衡原理和图论中的基本概念，提出了一种适用于化学平衡计算的赋权有向图。这种有向图具有三个重要性质：其一，边的方向改变则该边的权随着取逆(取原权的倒数或负值)；其二，顺乘逆除(或顺加逆减)一条路上的各权得到自起点至终点的累积权；其三，回路的权等于1(或零)。本文主要叙述这种图的提出及其在化学平衡中的初步应用。     

Diffusion of symmetrical and spherical solutes in protic,aprotic, and hydrocarbon solvents

The diffusion coefficients of a series of symmetrical tetraalkyltins (tetramethyltin, tetraethyltin, tetrapropyltin, tetrabutyltin, tetradodecyltin) of the gases argon, krypton, xenon, methane, and tetramethylmethane and of carbon tetrachloride and tetraethylmethane in hexane, decane, and tetradecane at 25°C have been determined using the Taylor dispersion technique. Diffusion coefficients for the gases in acetone, 2-propanol, 1-butanol, and 1-octanol were also determined. Deviations from the predictions of Stokes' law were found to be large, and the magnitude of the deviation can be directly related to solute size. The predictions of the Hubbard-Onsager equation were tested using the diffusion data.     

稀土及杂质元素对ZA27合金晶间腐蚀的影响

To understand the influence of impurities and rare earth elements in nature on the intergranular corrosion of the zinc-aluminum alloys, taking efficient methods to retard the inter granular corrosion, the atomic cluster of α phase grain boundary including impurities (Pb, Sn, Cd), rare earth elements (La, Y) and phase grain was constructed by computer programming based on the coincidence-site lattice theory. The recursion method was used to calculate the charge transfer over the grain boundary of α phase, and discuss influence of impurities (Pb, Sn, Cd) and Rare Earth elements (La, Y) on the electrode-potential of Zn and Al. The results shows that impurity elements (Pb, Sn, Cd) can increase the charge transfer between atoms over the grain boundary, leading to the large difference of electrode-potential between Zn and Al. Therefore the eroding is speeding up, but the RE element can reduce the charge transfer between atom sover the grain boundary, and lower the difference of electrode-potential between Zn and Al. Thus RE element is of the role of restraining the inter granular corrosion of zinc-aluminum alloys.     

Contributions to the Chemistry of the Binary Compounds of the Transition Elements

Phase and structural relationships of the sulfur, selenium, and tellurium compounds of the 4d and 5d transition elements of groups IV to VII of the periodic system are discussed. Homologous elements behave very similarly with respect to the chalcogens, and this is particularly the case for niobium and tantalum, and for molybdenum and tungsten. However, zirconium, niobium, and molybdenum have a greater tendency towards formation of chalcogen-poor phases than their homologues hafnium, tantalum, and tungsten. Subchalcogenides are known only for zirconium and niobium. The number of phases and the tendency towards formation of solid solutions are considerably smaller among the tellurides than among the sulfides and selenides. The crystal structures of the telluride phases also differ from those of the sulfide and selenide phases of analogous composition. In addition, a review of the phase and structural relationships of the arsenic and antimony compounds of the 4d and 5d transition elements of groups V to VII is given.     

表面活性剂与叶酸的相互作用及其对光氧化降解的影响

表面活性剂与有机小分子作用不仅能提高表面活性剂的聚集能力,还能提高小分子的溶解度、稳定性等应用性能,因此研究二者之间的相互作用机理对于促进表面活性剂的发展和实际应用具有重要意义。本工作提出了一种利用功能有机小分子调控表面活性剂聚集行为,进而提高不稳定小分子自身稳定性的新策略。利用表面张力、紫外可见吸收光谱、荧光光谱、动态光散射、等温滴定量热和核磁共振技术研究了在p H为7.0时,叶酸分别与十二烷基硫酸钠(SDS)、十二烷基三甲基溴化铵(DTAB)、季铵盐Gemini 12-6-12和季铵盐线性三聚12-3-12-3-12四种表面活性剂之间的相互作用及其导致的叶酸光氧化降解性能的变化,结果表明,阴离子表面活性剂SDS抑制叶酸光氧化降解的效率较低,而阳离子表面活性剂都能够显著抑制叶酸的光氧化降解,且随着表面活性剂寡聚度的增加,抑制效果增强,所需表面活性剂的浓度显著降低,寡聚表面活性剂12-3-12-3-12的抑制效率高达96%。     

Essential Oil of Cannabis sativa L: Comparison of Yield and Chemical Composition of 11 Hemp Genotypes

Cannabis sativa L. is an annual species cultivated since antiquity for different purposes. While, in the past, hemp inflorescences were considered crop residues, at present, they are regarded as valuable raw materials with different applications, among which extraction of the essential oil (EO) has gained increasing interest in many fields. The aim of the present study is the evaluation of the yield and the chemical composition of the EO obtained by hydrodistillation from eleven hemp genotypes, cultivated in the same location for two consecutive growing seasons. The composition of the EOs was analyzed by GC–MS, and then subjected to multivariate statistical analysis. Sesquiterpenes represented the main class of compounds in all the EOs, both in their hydrocarbon and oxygenated forms, with relative abundances ranging from 47.1 to 78.5%; the only exception was the Felina 32 sample collected in 2019, in which cannabinoids predominated. Cannabinoids were the second most abundant class of compounds, of which cannabidiol was the main one, with relative abundances between 11.8 and 51.5%. The statistical distribution of the samples, performed on the complete chemical composition of the EOs, evidenced a partition based on the year of cultivation, rather than on the genotype, with the exception of Uso-31. Regarding the extraction yield, a significant variation was evidenced among both the genotypes and the years of cultivation.     

Acidity,lipophilicity, solubility,absorption, and polar surface area of some ACE inhibitors

Computational chemical methods have been used to correlate the molecular properties of the 10 ACE inhibitors (captopril, enalapril, perindopril, lisinopril, ramipril, trandolapril, quinapril, fosinopril, benazepril, and cilazapril) and some of their active metabolites (enalaprilat, perindoprilat, ramiprilat, trandolaprilat, quinaprilat, fosinoprilat, benazeprilat, and cilazaprilat). The computed pK _a values correlate well with the available experimental values. In the dicarboxylic ACE inhibitors, the carboxyalkyl carboxylate group of the ACE inhibitors studied is more acidic than the C-terminal carboxylate. However, at physiological pH = 7.4 both carboxyl groups of ACE inhibitors are completely ionized and the dicarboxyl-containing ACE inhibitors behave as strong acids. The available experimental partition coefficients of these ACE inhibitors investigated are well reproduced by the neural network-based ALOGPs and the fragment-based KoWWiN methods. All parent drugs (and prodrugs), with the exception of fosinopril, are compounds with low lipophilicity. Calculated pK _a, lipophilicity, solubility, absorption, and polar surface area of the most effective ACE inhibitors for the prevention of myocardial infarction, perindopril and ramipril, were found similar. Therefore, it is probable that the experimentally observed differences in the survival benefits in the first year after acute myocardial infarction in patients 65 years of age or older correlate closely to the physicochemical and pharmacokinetic characteristics of the specific ACE inhibitor that is used.