食品中的假蛋白——三聚氰胺

自2008年6月起,我国甘肃等地陆续报告多例婴幼儿患泌尿系统结石的病例。经调查后发现,这些患儿多有食用三鹿牌婴幼儿配方奶粉的历史。石家庄三鹿集团公司则于9月11日发表声明,经自检发现部分批次三鹿婴幼儿奶粉受到三聚氰胺污染,公司决定立即全部召回2008年8月6日以前生产的三鹿婴幼儿奶粉。在随后开展的全国范围内婴幼儿配方奶粉三聚氰胺的专项检查中发现,有22家企业69批次产品检出了含量不同的三聚氰胺。     

三聚氰胺分析技术研究进展

三聚氰胺引发的宠物食品事件和婴幼儿配方奶粉事件使人们对食品和饲料中三聚氰胺的关注越来越多。现有的三聚氰胺分析技术(色谱法、质谱法、光谱法和毛细管电泳法等)虽然在一定程度上实现了快速和低检测限的要求,但依然存在着前处理程序复杂、耗时耗人工、成本高等诸多缺点。因此亟需开发快捷、简便、低成本的检测技术。本文旨在总结常规和新研发的检测技术,为三聚氰胺及其相关化合物的快速检测新技术开发提供参考。     

《化学与社会》——化学与和谐社会的可持续发展

近年来,发生了一系列与化学有关的社会事件,例如：“三聚氰胺”奶粉、厦门PX（对二甲苯）事件、危险化学品泄露、“齐二药”事故等,使化学这门学科背负了诸多负面效应。然而。要致力于社会的可持续发展,解决全球面临的诸多难题,建设环境友好型社会、改善人类生活、应对各类疾病、保障食品安全等,都离不开化学这门科学。     

辨别猪肉是否有“瘦肉精”方法

不久前,教育部组织专家对中国农业大学完成的“乳品真蛋白检测技术研究与方法筛选”项目进行了成果鉴定。2008年“三鹿肾结石奶粉事件”被曝光后,课题组及时推出了可以对乳品中真实的蛋白质含量进行测定的标准：NY／T1678—2008。该标准是迄今国内外与“蛋白质”相关的标准中,唯一不会将三聚氰胺误判为“蛋白质”的标准。     

液相色谱-串联质谱法快速同时测定婴幼儿配方乳粉中氯霉素、三聚氰胺、甲硝唑和洛硝达唑

建立了婴幼儿配方乳粉中三聚氰胺、氯霉素、甲硝唑和洛硝达唑残留的高效液相色谱-串联四极杆质谱联用测定方法.样品经碱性乙腈提取,以MGⅢ-C18色谱柱(150 mm× 2.1 mm,5 μm)分离,流动相为60 mmol/L乙酸铵溶液(含0.4‰甲酸)和甲醇,梯度洗脱,流速为0.25 mL/min.采用多反应监测正离子或负离子模式,可以同时对婴幼儿配方乳粉中的三聚氰胺、氯霉素、甲硝唑和洛硝达唑进行快速定性和定量测定.在优化条件下,4种化合物检出限为0.3 ～ 50.0μg/kg,方法回收率为61.4％ ～ 96.2％,相对标准偏差(RSD)为1.8％ ～9.8％.采用本方法测定了多种市售婴幼儿配方奶粉.本方法操作简单、测定结果准确,可用于婴幼儿配方奶粉中三聚氰胺、氯霉素、甲硝唑和洛硝达唑残留的同时快速测定.     

三聚氰胺分析检测方法的研究进展

介绍了三聚氰胺的物理和化学性质、用途,及其作为食品添加剂对人体健康的危害;重点总结了三聚氰胺现有的各种检测方法;并就各种检测方法的优劣进行了比较.指出三聚氰胺是一种工业原料,而在食品中添加三聚氰胺会危害人们的身体健康,甚至致人死亡;正因为如此,"三鹿奶粉事件"的发生为社会敲响了警钟,引起了人们对三聚氰胺及其衍生物的普遍关注.     

食品安全法三审八改明确食品不得免检

受“三鹿奶粉事件”警示，经过了两次审议的食品安全法草案（下称“草案”），在进入三审程序时又作了许多修改。其中明确增加了一条规定：“食品安全监督管理部门对食品不得实施免检”。     

2008安捷伦科技在中国

2008年，中国发生了太多太多让人刻骨铭心的事情，汶川的特大地震，北京奥运会的召开，奶粉中的三聚氰胺污染……，无不牵动着中国人的心。     

三聚氰胺ELISA快速试剂盒研发成功

尽管“三鹿奶粉”已成为过去式,但三聚氰胺这个幽灵依然困扰着食品安全领域。记者不久前了解到,杭州迪恩科技有限公司等单位参与的省重大科技专项重点农业项目“三聚氰胺、三聚氰酸及其类似物检测技术研究与应用”已研发成功,无论是检测性能还是快速检测准确性,均达到国际先进水平。     

液相色谱法测定三聚氰胺定性方法研究

自从三鹿婴幼儿乳粉中查出三聚氰胺事件以来,国家相继颁布了检测三聚氰胺的标准GB/T 22388-2008[1]和GB/T 22400-2008[2],全国各地质监机构和相关有资质的检验机构对市场流通及企业生产的乳制品进行了全面检查.     

Furyl- and thienyl-silatranes and germatranes

We review our research on the synthesis and study of the physical and biological properties of furyl- and thienylgermatranes and -silatranes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 725–732, June, 1992.     

Review and patents and literature

The use of the insect cell/baculovirus expression system for producing recombinant proteins of bacterial, plant, insect, and mammalian origin has become widespread. The popularity of this eukaryotic expression system is due to many factors, including (1) potentially high protein expression levels, (2) ease and speed of genetic engineering, (3) ability to accommodate large DNA inserts, (4) protein processing similar to higher eukaryotic cells (e.g., mammalian cells), and (5) ease of insect cell growth (e.g., suspension growth). The following review of the literature discusses two engineering aspects of recombinant protein synthesis by insect cell cultures: bioreactor scale-up and insect cell line selection. Following this review patent abstracts and additional literature pertaining to expression of recombinant proteins in insect cell culture are listed.     

Ground- and excited-state aromaticity and antiaromaticity in benzene and cyclobutadiene

The aromaticity and antiaromaticity of the ground state (S 0), lowest triplet state (T 1), and first singlet excited state (S 1) of benzene, and the ground states (S 0), lowest triplet states (T 1), and the first and second singlet excited states (S 1 and S 2) of square and rectangular cyclobutadiene are assessed using various magnetic criteria including nucleus-independent chemical shifts (NICS), proton shieldings, and magnetic susceptibilities calculated using complete-active-space self-consistent field (CASSCF) wave functions constructed from gauge-including atomic orbitals (GIAOs). These magnetic criteria strongly suggest that, in contrast to the well-known aromaticity of the S 0 state of benzene, the T 1 and S 1 states of this molecule are antiaromatic. In square cyclobutadiene, which is shown to be considerably more antiaromatic than rectangular cyclobutadiene, the magnetic properties of the T 1 and S 1 states allow these to be classified as aromatic. According to the computed magnetic criteria, the T 1 state of rectangular cyclobutadiene is still aromatic, but the S 1 state is antiaromatic, just as the S 2 state of square cyclobutadiene; the S 2 state of rectangular cyclobutadiene is nonaromatic. The results demonstrate that the well-known "triplet aromaticity" of cyclic conjugated hydrocarbons represents a particular case of a broader concept of excited-state aromaticity and antiaromaticity. It is shown that while electronic excitation may lead to increased nuclear shieldings in certain low-lying electronic states, in general its main effect can be expected to be nuclear deshielding, which can be substantial for heavier nuclei.     

Determination and study on residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil

A QuEChERS (quick, easy, cheap, effective, rugged, and safe) method for the determination of benazolin-ethyl and quizalofop-p-ethyl in rape and soil by high-performance liquid chromatography-tandem mass spectrometry has been developed in this study. The residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil were determined with the developed method. The half-lives of benazolin-ethyl in rape straw and soil were 3.7–5.1 days and 14.3–26.3 days, respectively. The half-lives of quizalofop-p-ethyl in rape straw and soil were 5.0-6.1 days and 0.3–9.7 days, respectively. The residue of benazolin-ethyl and quizalofop-p-ethyl in rapeseed and soil were below the detection limit (i.e., 0.5?mg?kg^?1, the maximum residue level of European Union for quizalofop-p-ethyl).     

Syntheses and structures of P-anilino-P-chalcogeno- and P-anilino-P-iminodiazasilaphosphetidines and their group 12 and 13 metal compounds

The P-anilino-P-chalcogeno(imino)diazasilaphosphetidines [Me(2)Si(mu-N(t)Bu)(2)P=E(NHPh)] (E = O (3), S (4), Se (5), N-p-tolyl (6)) were synthesized by oxidizing the P-anilinodiazasilaphosphetidine [Me(2)Si(N(t)Bu)(2)P(NHPh)] (2) with cumene hydroperoxide, sulfur, selenium, and p-tolyl azide, respectively. The lithium salt of 4 reacted with thallium monochloride to produce ([Me(2)Si(mu-N(t)Bu)(2)P=S(NPh)-kappaN-kappaS]Tl)(7), which features a two-coordinate thallium atom. Treatment of 4-6 with AlMe(3) gave the monoligand dimethylaluminum complexes ([Me(2)Si(mu-N(t)Bu)(2)P=E(NPh)-kappaN-kappaE]AlMe(2)) (E = S (8), Se (9), N-p-tolyl (10)), respectively. In these complexes the aluminum atom is tetrahedrally coordinated by one chelating ligand and two methyl groups, as a single-crystal X-ray analysis of 8 showed. A 2 equiv amount of 4-6 reacted with diethylzinc to produce the homoleptic diligand complexes ([Me(2)Si(mu-N(t)Bu)(2)P=E(NPh)-kappaN-kappaE](2)Zn)(E = S (11), Se (12), N-p-tolyl (13)). A crystal-structure analysis of 11 revealed a linear tetraspirocycle with a tetrahedrally coordinated, central zinc atom.     

多环芳二酐型聚酯亚胺膜的透气性能

多环芳二酐型聚酯亚胺膜的透气性能李悦生，丁孟贤，徐纪平（浙江大学高分子科学与工程研究所，杭州，３１００２７）（中国科学院长春应用化学研究所）关键词聚醚酰亚胺，聚酯酰亚胺，膜，透气性通常的聚酰亚胺加工性能较差，在芳环二酐的苯环间引入醚键等柔性基团后，其...