食品中甜蜜素的紫外分光光度法测定

采用紫外分光光度法测定食品中的甜蜜素。该法在０．２～１．０ｇ／Ｌ甜蜜素范围内符合比尔定律,回收率为９５．０％～１０２．７％,相对标准偏差（ＲＳＤ）为２．６６％～５．４０％,食品中共存的苯甲酸、山梨酸、糖精钠在０～１０．０ｇ／Ｌ范围内,色 ０～２．０ｇ／Ｌ范围内不影响测定。方法简捷,准确。     

功能聚间苯二胺膜用于免疫传感器分析

以电化学聚合法在石墨电极上获得聚间苯二胺膜（ＰＭＰＤ），并建立了快速、灵敏的膜质量检验方法：辣根过氧化物酶（ＨＲＰ）标记ＰＭＰＤ膜－邻苯二胺（ＯＰＤ）反应法，对聚合、活化等条件作了研究；进一步制成了检测乙肝表面抗原（ＨＢｓＡｇ）和检测鼠免疫蛋白（ＭＩｇＧ）的免疫电极，对血清样品作了检测．结果表明：２．５Ｖ电池电压下，于含０．１２ｍｏｌ／ＬＭＰＤ的１．２ｍｏｌ／ＬＨ２ＳＯ４中聚合２０ｍｉｎ，再以３０ｇ／Ｌ浓度的戊二醛活化４ｈ，所得ＨＲＰ标记电极及免疫电极重现性好；检测ＨＢ－ｓＡｇ和ＭＩｇＧ的线性范围分别为０．１～３．２ｍｇ／Ｌ及０．１～１０ｍｇ／Ｌ     

三波长K系数分光光度法同时测定痕量磷,砷,硅

１引言以碱性染料光度法同时测定磷、砷、硅已有报道，但需加入掩蔽剂或经还原－萃取等分离。本文用三波长Ｋ系数法原理，由计算机选出最佳波长组合，不经分离、掩蔽，于一份试液中同时测定痕量磷、砷、硅，其线性范围分别为４０．０～２４０．０μｇ／Ｌ、３２．０～１２０．０μｇ／Ｌ、３２．０～３２０．０μｄ／Ｌ。用于合成样品测定，结果令人满意。２实验部分２．１仪器与试剂７２２型光栅分光光度计。硅标准溶液：用高纯ＳｉＯ２（９９．９９％）以常法熔融配成ｐＨ约１．５的溶液，含硅０．１００ｇ／Ｌ；磷标准溶液：用ＫＨ２ＰＯ…     

单柱离子色谱法同时测定磷酸中痕量钠（Ⅰ）和铁（Ⅲ）

以酒石酸－乙二胺为淋洗液的单柱离子色谱法同时测定磷酸中痕量钠（Ⅰ）和铁（Ⅲ）。淋洗液最佳浓度为４．０ｍｍｏｌ．Ｌ￣（－１）、酒石酸／１．０ｍ　ｍｏｌ·Ｌ￣（－１）乙二胺。最低检测限为Ｎａ￣＋０．０５μｇ／ｍＬ、　Ｆｅ３＋　０．４５μｇ／ｍＬ。电导检测灵敏度为２．０μｇ／ｃｍ。线性范围Ｎａ￣＋、Ｆｅ３＋０．２～１．５×１０３μｇ／ｍＬ、２．５～１．０×１０３μｇ／ｍＬ。相对平均偏差Ｎａ￣＋为２．０３％、Ｆｅ３＋为０．８３％。平均回收率Ｎａ￣＋为９８．２６％、Ｆｅ３＋为９７．６２％。本法简便、快速、准确、选择性好。     

氢化物发生电感耦合等离子体原子发射光谱法同时测定水和生物样品中…

研究了一种小型同心氢化物发生配置一个气液分离器后与多道ＩＣＰ－ＡＥＳ联用，同时测定水和生物样品中砷、铋、锑、硒的方法。检出限为砷０．４μｇ／Ｌ，铋０．５μｇ／Ｌ，锑１．４μｇ／Ｌ，硒０．５μｇ／Ｌ，相对标准偏差为砷２．７％，铋１．５％，锑２．７％，硒１．９％。用本法测定美国和国家标准物质中的氢化元素，结果满意。     

倒数示波计时电位法同时测定粮食中Cu、Pb含量

在分别含有２ｇ／Ｌ乙二胺与＊１０＾－４ｍｏｌ／Ｌ８－羟基喹啉（Ｏｘｉｎｅ）和０．３ｍｏｌ／Ｌ的氢氧化钠淀粉液中,Ｃｕ＾２＋、Ｐｂ＾２＋具有良好的示波图。其切口电位分别为－０．８５Ｖ,－１２０Ｖ（ｖｓ．ＳＣＥ）,二者相差０．３５Ｖ,能够分辨,可同时测定,本方法应用于大米中Ｃｕ、Ｐｂ含量的同时测定,检出限分别为５．８μｇ／Ｌ（Ｃｕ）、１０．０μｇ／Ｌ（Ｐｂ）,平均回收率为９６．０％、１０２．０％。     

单扫描极谱法连续测定人发中的微量元素锌铁锰铜

本提出在０．１５ｍｏｌ／Ｌ乙二胺－７．５×１０＾－３ｍｏｌ／Ｌ三乙醇胺－２．５×１０＾－２ｍｏｌ／Ｌ硫氰酸钾底液中单扫描极谱法测定锌、铁、锰，续加硫酸（０．３ｍｏｌ／Ｌ）测定铜的方法，峰电位分别为－１．４２Ｖ，－１．６３Ｖ，－１．７１Ｖ，－０．４８Ｖ（ｖｓ．ＳＣＥ），线性范围：０．０５～１．４μｇ／ｍＬＭｎ，０．０４～１μｇ／ｍＬＣｕ，最低检出浓度．０３，０．０５，０．０２，０．０４μｇ／ｍＬＭ     

用石墨炉原子吸收法测定水质中微量砷,硒的探讨

采用石墨炉原子吸收法测定水中微量砷，硒，经大量实验条件摸索，选择不同仪器分析工作条件，找出了最佳升温程序条件，特别是原子化时气流控制，使分析方法的检出限降低为：Ａｓ０．６μｇ／Ｌ，Ｓｅ０．５μｇ／Ｌ。线性范围；Ａｓ０．０００－０．１２０ｍｇ／Ｌ，Ｓｅ０．０００－０．０２４ｍｇ／Ｌ；精密度，相对标准偏差分别为：Ａｓ１．２６％，３．６７％，Ｓｅ２．５６％，４．５７％，回收率为：Ａｓ９８．０％－１１０．     

毛细管气相色谱法测定速效伤风胶囊中对乙酰氨基酚、咖啡因、马来酸氯苯那敏的含量

用５％Ｐｈ－Ｍｅ－Ｓｉｌｉｃｏｎｅ毛细管色谱柱，ＦＩＤ，二阶程序升温，以正十六烷作为内标物测定速效伤风胶囊中对乙酰氨基酚、咖啡因、马来酸氯苯那敏的含量。浓度线性范围：对乙酰氨基酚４～２０ｇ／Ｌ，咖啡因０．０８４～０．４２ｇ／Ｌ，马来酸氯苯那敏０．１５～０．７５ｇ／Ｌ。平均回收率（ｎ＝５）：对乙酰氨基酚９９．６２％（ＲＳＤ＝０．４４％）咖啡因９６．４６％（ＲＳＤ＝１．３２％），马来酸氯苯那敏９８．５５％（ＲＳＤ＝０．６５％）。     

气相色谱-质谱法测定氯氮平及其去甲基代谢物

建立了测定人血清中氯氮平及其去甲基代谢物的柱前衍生化气相色谱－质谱选择离子监测的分析方法。以三氟乙酸酐作酰化剂,对衍生化条件和样品预处理方法实施了优化。氯氮平和去甲氯氮平的线性范围为１～１２８μｇ／Ｌ,最低检测浓度：氯氮平为０．１μｇ／Ｌ,去甲氯氮平为０．２μｇ／Ｌ,两者的回收率均大于８３％,相对标准偏差都小于１０％。将所建立的方法应用于服用细胞色素氧化酶Ｐ４５０１Ａ２抑制剂前后低剂量氯氮平的药代动力学自身对照试验中,结果显示氯氮平的代谢水平明显受Ｐ４５０１Ａ２活性的影响。     

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%.     

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.     

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.     

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.     

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.