氢化物发生辅助雾化火焰原子吸收法测定水中铅

研究了一种提高火焰原子吸收测定铅灵敏度的新方法——氢化物发生辅助雾化的火焰原子吸收法；方法采用硼氢化钠与铅(Ⅳ)在原火焰原子吸收雾化器喷口处反应生成氢化物，以提高火焰原子吸收法的雾化效率；采用重铬酸钾一酒石酸预处理体系，重铬酸钾氧化样品中铅(Ⅱ)为铅(Ⅳ)，酒石酸稳定铅(Ⅳ)的亚稳态化合物；对各种实验参数和干扰情况也进行了研究；方法操作简单、快速，灵敏度比通常的火焰原子吸收法提高了6．8倍；检出限(K=3，n=11)为6．64μg/L，线性范围为0．021～3．2mg／L；测定水样的回收率达94％～99％。     

茶多酚中微量铜的原子吸收光谱分析

叙述了干灰法消化样品后，利用原子吸收光谱仪测定茶多酚中微量铜的方法。该法的回收率在９０％￣１０５％之间；对同一样品进行６次平行测定，其相对标准偏差为３．９％，结果可靠，方法简便；可用于实际样品分析。     

交联壳聚糖富集分离冷原子吸收分光光度法测定环境水样中痕量无机汞

报道了采用不溶于酸碱的交联壳聚糖，以ＥＤＴＡ为络合剂性富集分离，冷原子吸收分光光度法直接测定环境水样中痕量无机汞的方法，并发分析的最佳条件进行了探讨。地分析实际水样，回收率为９４％－９８％；检测下限为７．８ｎｇ／Ｌ；相对标准偏差小于６％。     

用毛细管电泳同时分析饮料中合成色素和防腐剂

建立了饮料中合成色素与防腐剂的毛细管电泳分离、紫外吸收检测分析方法；详细研究了缓冲体系组成与浓度对分离效果的影响。在优化条件下，１１ｍｉｎ完成５种色素和２种防腐剂的分析，检测限为１５～５８ｍｇ／Ｌ；保留时间精度为０３９％～１１％；峰高测量精度为１４％～２９％；该法成功地用于实际样品的分析。     

甘薯中微量钙铁的原子吸收分光光度法测定

研究了用原子吸收分光光度法测定甘薯中的微量钙、铁的含量；采用高温灰化法对样品进行处理，并对40多种不同品种和不同种植地区的甘薯进行了实样测定和含量差异比较；对9个样品进行钙和铁的加标回收试验，测定的回收率在91％－107％之间，相对标准偏差RSD（n=9)分别为4．6％、5．4％，结果令人满意。     

石墨炉原子吸收分光光度法测定茶叶中的铅

采用石墨炉原子吸收分光光度法测定了产自福建等地茶叶中的铅含量。方法的线性范围为0—80μg/L，回收率达91．7％-101．5％，相对标准偏差1．47％-3．88％。茶样检测结果表明，铅合格率为92．0％；不同茶类铅含量前3位由高到低依次为绿茶，乌龙茶，红茶；各类茶铅含量平均值为1．069mg／kg。     

火焰原子吸收法测定癌细胞中的钙、镁、铜等金属元素

采用火焰原子吸收法直接测定一系列(食道、胃)癌细胞及其近旁的正常细胞中的钙、镁、铜等金属含量。结果表明，钙的变异系数为1．83％-4．19％，回收率为99．8％-104．0％；镁的变异系数为0．02％～1．18％，回收率为97．2％-98．5％；铜的变异系数为3．80％-6．68％，回收率为90．5％～99．7％；均得到较满意的结果，具有一定的参考价值。     

锆硼陶瓷材料中总硼分析方法研究

对锆硼陶瓷材料中总硼的分析方法进行了研究，采用硫酸和硫酸铵及重铬酸钾氧化两步溶解法分解样品，氮气载带硼酸三甲酯蒸馏分离硼与锆（氦气流速150mL/min水溶加热，NaOH溶液吸收），材料中成分为Zr粉＋B4C粉，Zr含量≥99％（ut），经阳离子交换法除去吸收液中Na后采用ICP-AES法测定硼。方法的相对标准偏差（n=6）小于2．0％；标准加入回收率为99％。     

非螯合物浊点萃取-墨炉原子吸收法测定水中痕量铊（Ⅲ）

建立不需形成螯合物的浊点萃取-石墨炉原子吸收法测定水中铊a田D的新方法。用浊点萃取技术富集水中铊a田D，石墨炉原子吸收法测定。经考察，浊点萃取环境水体中铊a田D的最优条件为pH12，90℃水浴2h，Triton X-114浓度2．0g／L；在优化后实验条件下，方法测定铊a田D的检出限为0．018彬L；相对标准偏差为8．89％-13．7％（C=0．1μg／L及1．0μg／L，n：7）；加标回收率为98．0％-101％。本法适于水中痕量铊（Ⅲ）的测定。     

火焰原子吸收光谱法直接测定食用菌中的铅和镉

采用火焰原子吸收法直接测定了食用菌中铅和镉的含量。方法灵敏、准确，测定时无须富集、萃取，操作简便，快速，铅和镉的相对标准偏差分别在3．3％～7．3％和3．1％～7．5％之间。回收率在94％～106％和95％～105％之间；检出限为0．016mg/L和0．008mg/L。     

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.