导数伏安法同时测定5种混合人工合成色素

建立了同时测定胭脂红、柠檬黄、日落黄、赤藓红、苋菜红5种食用人工合成色素的1.5次线性扫描伏安法,并讨论了人工合成色素在悬汞电极上的反应机理.本方法简单快速,灵敏度高,重现性好,可以不经分离同时测定食品中的多种着色剂.     

高效液相色谱-串联质谱法测定染发剂中11种苯胺和苯酚类染料

1引言在众多染发剂产品中,人工合成的氧化型染发剂由于染色效果好、色调丰富、颜色持久等优点,应用极为广泛。但这类染发剂多以芳香胺和/或酚类组分为有效成分,易引起人体过敏等不良反应,长期使用甚至可能导致"三致"。鉴于氧化型染发剂的安全性问题,我国《化妆品卫生规范》明确规定了其禁用和暂时允许使用组分的类别及限制条件,并推荐     

染发剂与人体健康

扼要介绍头发染色的机理,重点阐述染发剂的种类及其功能：天然植物类染发剂安全有效;人工合成类染发剂中的有机合成染发剂应用最广泛,但苯胺类物质对人体有害;人工合成类中的无机染发剂含有重金属离子,容易导致染发中毒。     

高效液相色谱法测定黄桃罐头中8种合成着色剂

应用高效液相色谱法测定了黄桃罐头中柠檬黄、苋菜红、靛蓝、胭脂红、日落黄、诱惑红、亮蓝和赤藓红等8种人工合成着色剂的含量。样品用乙醇-氨水-水溶液提取后,经Sep-Pak PlusQMA固相萃取柱净化处理,以甲醇和乙酸铵溶液为流动相梯度洗脱,经Inertsil ODS-3V(4.6 mm×250 mm,5μm)色谱柱分离,用二极管阵列检测器检测。8种着色剂的质量浓度在0.1~20.0 mg.L-1范围内与其峰面积呈线性关系,测定下限(10S/N)在0.20~0.50 mg.kg-1之间。方法对8种着色剂的平均回收率分别为柠檬黄94.3%~96.2%、苋菜红93.3%~99.6%、靛蓝77.9%~84.7%、胭脂红95.0%~101.0%、日落黄94.6%~103.0%、诱惑红94.1%~104.0%、亮蓝96.4%~104.0%、赤藓红85.9%~89.7%,相对标准偏差(n=6)均小于9.0%。     

警惕食品包装材料着色剂迁移

<正>江苏常州检验检疫局食品接触材料国家重点实验室在对有色塑料饭盒、塑料杯等食品接触材料进行检测时,发现部分样品存在着色剂迁移(脱色)的现象,从而造成了食品或食品模拟物染色的现象。着色剂主要分为有机着色剂和无机着色剂。部分无机着色剂含有毒性较大的重金属,特别是汞、镉、铅、铬等。有机着色剂也常会分解一些致癌、致突变等有机毒害物质,如一些偶氮染料会裂解释放苯胺、联苯胺之类的致癌芳香胺。     

全氟辛酸和全氟辛烷磺酸人体暴露途径解析及其污染控制技术*

全氟辛酸（PFOA）和全氟辛烷磺酸（PFOS）是人工合成全氟化合物的典型代表。近年来,大量的环境调查数据表明它们普遍存在于多种环境介质、生物体甚至人体中,呈现出全球分布的态势,具有环境持久性和生物富集性,对人体健康存在潜在的危害,已成为一类新的环境持久性有机污染物而引起人们广泛的关注。本文介绍了PFOA和PFOS的环境来源和传输途径,解析了人体暴露的三种主要途径以及在食物、饮用水和空气/灰尘中的污染现状,并就围绕着它们所开展的污染控制技术方面的研究进行了评述。在此基础上,通过分析目前研究中所存在的问题,对今后的发展方向和研究重点进行了展望。     

略谈甲醛聚糖研究的进展

供给人体热:量的食物主要是碳水化合物、脂肪和蛋白质。目前,我国人民膳食中的热量主要来自碳水化合物。用人工合成的方法获得可食用的碳水化合物,这是化学和生物化学工作者长期以来进行的最艰巨的探     

电感耦合等离子体质谱法测定壁纸中的20种元素

正壁纸也称为墙纸,是一种应用广泛的室内装饰材料。为改善或增加壁纸材料的性能,某些壁纸材料中会添加防霉剂、防腐剂、消毒杀菌剂或着色剂[1]等。这些助剂中可能含有有害元素如铬、砷、锌等[2],着色剂中可能存在铅、钴等元素,金属壁纸中可能存在镍、铜等元素[3]。壁纸中含有的可溶性铬、砷、硒、镉、锑、钡、汞、铅、钴、镍、铜、锌、锂、铍、钛、锰、铁、锶、钼、铊等元素,对人体均有不同程度的毒     

高效液相色谱法测定染发剂中α-萘酚

在化妆品行业,α-萘酚作为着色剂被用于一些染发剂中。α-萘酚有致癌、致畸、致突变性等潜在危害性,也是环境污染物。人体接触后可引起烧灼感、咳嗽、头痛、眩晕、呕吐等症状,大量吸收后会引发肾炎、结膜炎、皮炎和血溶性贫血等疾病。我国规定α-萘酚在染发剂中最大浓度不应超过0.5%。因此,如何简便、准确、快速地检测α-萘酚尤为重要。已有相关文献报道了染发剂中α-萘酚的高效液相色谱-紫外检测的测定方法,但因为检测波长选择不当,导致分析方法的灵敏度     

喹啉的生物降解动力学

喹啉是一种典型的氮杂环化合物,在化工、医药及农药生产中经常用作溶剂和原材料．喹啉又是一种毒性大、致变性和致癌性强的物质,对人类、水生生物及植物有着很大的危害．因此随着工业废水特别是焦化废水的排放,使喹啉成为水中常见的污染物．喹啉的结构为许多人工合成化合物的基本结构,而人工合成化合物一般不易被自然界中固有的微生物识别,所以多数为难以生物降解的化合物,研究喹啉的生物降解能为研究其他人工合成化合物的生物降解提供有益的启示．人们对喹啉的降解途径进行了有益的探索［１ -３］,对喹啉降解的动力学也进行了研究［…     

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.     

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.     

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.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

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.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

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.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

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.