氢化物原子荧光光谱法测定虾中砷和汞

建立了氢化物原子荧光法同时测定虾中砷和汞的方法。研究了样品前处理及实验条件对测定砷、汞的原子荧光强度的影响，并探讨了共存离子对测定砷、汞的干扰和消除的方法。本方法具有操作简便、快速、灵敏度高等优点，砷和汞的检出限分别为0．026μg/L和0．020μg／L；相对标准偏差分别为1．7％～9．4％和1．2％～9．4％；回收率为98％～106％。     

HPLC-ICP-MS测定中药中砷的形态

报道了高效液相色谱-电感耦合等离子体质谱（HPLC—ICP-MS）联用技术测定中药中砷的形态，采用阴离子交换柱，以0．2mmol／L EDTA和2mmol／L NaH2PO4的溶液为流动相，pH6．0，流速为1．0mL／min，成功分离了亚砷酸（AsⅢ）、砷酸（AsV）、甲基砷（MMA）和二甲基砷（DMA）。检出限分别为0．67μg／L（AsⅢ），0．85μg／L（DMA），0．43μg／L（MMA），0．70μg／L（AsV）。中药样品经过（1＋1）甲醇和水的溶液超声提取，离心、过滤、氮气吹干甲醇，超纯水定容。样品加标平均萃取回收率分别为：92．8％（AsⅢ），108％（DMA），104％（MMA），101％（AsV），相对标准偏差（RsD，n=7）均小于10％。     

原子荧光光谱法测定水中的痕量砷、硒、汞

建立了测定水中痕量砷、硒、汞三种元素的原子荧光光谱法。利用AFS-230型双道原子荧光光度计可双道分析的特点，采用氢化物发生原子荧光光谱法联合测定砷、硒，采用冷原子荧光光谱法单独测定汞。As、Se、Hg的线性相关系数分别为：0．9994、0．9995、0．9994，检出限分别为1．60、0．89、0．029μg／L，测定结果的相对标准偏差分别为3．8％、5．7％、4．6％，平均加标回收率分别为100．1％、101．4％、99．6％。     

高压釜消解-氢化物发生原子荧光光度法测定土壤中的砷、硒

对高压釜密封消解一氢化物发生原子荧光法测定土壤中砷、硒的方法进行了研究。采用HNO3-HClO4作消解剂，在最佳的消解条件和测定条件下，测定砷、硒的线性回归方程分别为I=244．1c 1．03、I=88．26c 2．86．线性范围均为0．50～10．00μg／L，相关系数均为0．9999，检出限均为0．0002μg/mL。测定土壤中砷、硒的回收率分别为90％～105％、89％～104％，RSD分别为2．2％～4．0％、1．9％～3．1％。     

氢化物-原子荧光法同时测定大米中的砷和硒

采用氢化物-原子荧光光谱法测定大米中的砷和硒。在0～10μg／L范围内,砷和硒的浓度与荧光强度呈线性关系,相关系数分别为0．9996和0．9998,加标回收率分别为96．2％～100．8％和98．1％～107．6％,砷、硒测定结果的相对标准偏差分别不大于6．8％,5．7％（n=6）。     

氢化物发生-原子荧光光谱法同时测定水中砷和锑

建立在硝酸介质中用氢化物发生-原子荧光光谱法同时测定水中砷和锑的方法。优化了仪器工作条件、酸度、硼氢化钾及还原剂浓度。砷、锑的线性范围为0～10．0μg／L;检出限分别为0．02,0．01μg／L;测定结果的相对标准偏差分别为1．77％～3．72％,2．95％～4．87％（n=6）;加标回收率分别为98％106％,96％105％。该法操作简便,灵敏度高,快速,便于推广,适用于水中砷和锑的同时测定。     

氢化物发生-原子荧光光谱法测定环境水样中的砷（Ⅲ）、砷（V）

用氢化物发生-原子荧光光谱法测定环境水样中的砷(Ⅲ)和砷(V)，在0～100μg／L范围内砷的浓度与荧光强度呈线性关系，相关系数r=0．9999。测定结果的相对标准偏差为0．7％，检出限为0．08μg／L。与二乙氨基二硫代甲酸银光度法进行比对，经F检验和t检验，两种方法无显著性差异。     

微波消化-氢化物发生原子吸收光谱法测定鳗鱼中的汞

对微波消化一氢化物发生原子吸收光谱法测定鳗鱼中的汞进行了研究。采用HNO3-H2O2消化体系，利用微波消化样品，以硼氢化钠为还原剂，用氢化物发生原子吸收光谱法测定鳗鱼中的汞。在最佳微波消化条件和测定条件下，线性范围为0～40．0μg／L，检出限为0．02μg／L，测定结果的相对标准偏差为2．3％-3．6％，回收率为93．2％-101．0％。     

萃取富集-火焰原子吸收法测定环境水中铜、锌、铅、镉

用2-琉基苯并噻唑／醋酸丁酯pH7～8萃取体系，预浓集以后，用火焰原子吸收测定环境水中癌量Cu，Zn，Cd、Pb，回收率在95％～105％，相对标准偏差为2％～5％（x=6)，植出限为Cu0．2μg／L，Zn0．08μg／L、Cd0．03μg／L、Pb0．8μg／L。     

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砷、铋、锑和硒

研究了一种小型同心氢化物发生器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。     

SYNTHESIS AND REACTIONS OF SOME 2-THIENYL- AND 2-THENOYL-DERIVATIVES OF THIAZOLE AND THIADIAZOLINE AND THEIR SELENIUM ANALOGS

Abstract

2-(Thiocyanatoacetyl)thiophene 2 and its selenium analog 3 couple with diazotized anilines and yield 3-aryl-2-imino-5-(2-thenoyl)-2,3-dihydro-1,3,4-thiadiazoles 6 and 3-aryl-2-imino-5-(2-thenoyl)-2,3-dihydro-1,3,4-selenadiazoles 7 respectively. The reactions of both 6 and 7 with nitrous acid, acetic anhydride and benzoyl chloride are described. Azo coupling of 2-amino-4-(2-thienyl)thiazole 17 and its selenazole analog 18 with diazotized anilines yielded the arylazo derivatives 19 and 20 respectively. Reaction of the hydrazidoyl bromide 16 with potassium thiocyanate, potassium selenocyanate, thiourea and selenourea yields 6, 7, 19, and 20 respectively.     

生物质热解、加氢热解及其与煤共热解的热重研究

在加压热天平上用非等温热重法进行生物质（锯末、稻壳）在Ｎ２气氛下的热解和加氢热解研究。考察了升温速率（５～２５℃／ｍｉｎ）和压力（０．１～７ＭＰａ）的影响，求取了热解动力学参数，并研究了生物质与煤在常压Ｎ２气下的共热解过程。研究结果表明：生物质在４００℃左右即完成热解反应，总失重率大于７０％（Ｗ％，ｄａｆ．），热解时仅一个峰位于３００℃左右；与煤热解行为相同，随升温速率及压力的升高，转化率下降，ＤＴＧ峰移向高温，但由于热解反应在较低温度下进行，氧气的存在对生物质热解ＴＧ和ＤＴＧ的影响远小于煤热解。证明生物质热解以其内部氢对自由基的饱和及分子重排反应为主。生物质热解可用一级反应动力学处理，主要热解阶段及表现活化能分别为：锯末，２６７～３１４℃，６９．６６ｋＪ／ｍｏｌ；稻壳，２８３～３１０℃，５３．４５ｋＪ／ｍｏｌ；生物质由于与煤的热分解温度相差很大，因而在其共热解过程中无协同作用。     

温度及pH敏感N-异丙基丙烯酰胺/β-环糊精水凝胶的合成与性能研究

用顺丁烯二酸酐 (MAH)对具有分子包结能力的 β 环糊精 (β CD)进行化学改性 ,合成出了丁烯二酸单酯化 β CD单体 (MAH β CD) .通过氧化还原自由基引发MAH β CD与N 异丙基丙烯酰胺 (NIPA)聚合 ,合成出含 β CD结构单元的新型水凝胶 .用核磁共振、红外光谱及元素分析对MAH β CD单体及共聚物的结构和组成进行了表征 .溶胀研究结果表明 ,该水凝胶具有较好的pH、温度及离子强度敏感性 ;并且水凝胶在较高羧基(—COOH)含量和弱碱环境中 ,仍能表现出明显的温敏性     

MECHANICS AND THE EVOLUTION AND FUNCTIONAL MORPHOLOGY OF CONCHOSTRACAN CARAPACE MECHANICS AND THE EVOLUTION AND FUNCTIONAL MORPHOLOGY OF CONCHOSTRACAN CARAPACE

Conchostracans, with a laterally compressed body enclosed between two symmetric valves, live swimming in fresh or brackish water. The carapace valve has a number of growth bands with various sculptures. The general trend of sculptural evolution is from smooth to punctate-minute polygon-medium reticulation-large reticulation, while these punctate, polygonal and various reticulate patterns may separately develop into various radial ridges. The development of sculpture can be well explained by mechanical principle. Functional morphology of carapace is discussed in the light of mechanics in this paper.     

PHOTOLYSIS AND RADIOLYSIS OF NITROMETHANE AND NITROETHANE

Abstract— Prolonged photolysis of nitromethane and nitroethane in liquid and vapour phases, with simultaneous photolysis of the nitrogen dioxide formed, was studied in the absence and presence of cupric oxide. A high-pressure quartz immersion lamp providing the full range of visible and u.v. spectrum, with a high output of radiation at 366 and 313 mμ, was employed as source of light. The products of photolysis were detected by microanalytical methods, infrared-absorption spectrum analysis and gas chromatography. Photolysis of liquid nitro-alkanes resulted in formation of many compounds; saturated hydrocarbons, and in the case of nitroethane, ethylene, were submitted to detailed examination. Photolysis in the vapour phase was carried out in a specially designed glass apparatus. The main products were nitrogen dioxide, aldehydes and polyaldehydes; hydrocarbons were not estimated.
Liquid nitromethane and nitroethane were also irradiated with γ-rays from a ⁶⁰Co source. The radiolysis products were similiar to those obtained on photolysis. The mechanism of photolytic decomposition of nitroalkanes is proposed and discussed.     

四个酰基硫脲衍生物及其配合物的合成与表征

本文报道了四个Ｎ－酰基硫脲衍生物及其Ｃｕ＾２＋，Ｎｉ＾２＋，Ｃｄ＾２＋，Ｓｎ＾４＋配合物的合成。用质谱、红外光谱、紫外光谱对它们进行了结构、性质表征。配体与金属离子配位主要是通过硫原子进行，配合物都是非离子型的。     

SURFACE ENTHALPY AND ENTROPY AND THE PHYSICO-CHEMICAL NATURE OF HYDROPHOBIC AND HYDROPHILIC INTERACTIONS

The attractive Interactions between typically hydrophobic molecules such as hexane or CCl₄, and the repulsive Interactions between extremely hydrophilic molecules such as poly(ethylene oxide) (PEO), when immersed in water, as well as the interactions between these molecules and water, have been examined from a surface thermodynamic viewpoint, taking the changes in surface free energy into account, as a function of temperature. It was found that attractive hydrophobic Interactions are not, as vas generally believed up to now, invariably entropic. Hydrophobic Interactions can be mainly enthalpic or mainly entropic, or more or less equal mixtures of both, depending on each individual case; however, all hydrophobic interactions are polar (in the sense of Lewis acid-base) in nature. Repulsive hydrophilic interactions are enthalpic, and also polar in nature. The interaction between hydrophobic solutes and water is mainly enthalpic, and is apolar in nature.     

CHLOROPHYLL a AND CAROTENOID AGGREGATES AND ENERGY MIGRATION IN MONOLAYERS AND THIN FILMS

Abstract— The spectra of absorption, fluorescence and excitation of monolayers and thin films containing chlorophyll a together with a carotenoid (cis-β-carotene, trans-β-carotene, fucoxanthin, or zeaxanthin), were measured at — 196°C. The concentration ratios used, (Chl)/(Car), were 6:1, 4:1, 3:1, 2:1, 1:1 and 1:3, and the area densities, 3·70, 2·55, 1·76, 0·71, 0·37 and 0·17 nm²/pigment molecule. In dilute monolayers, (3·70 nm²/molecule), with a constant concentration ratio (Chl)/(Car) = 3:1, evidence of three β-carotene forms, with absorption bands at 460, 500 and 520 nm (C₄₆₀, C₅₀₀ and C₅₂₀), and of a chlorophyll a form with an absorption band at 669–672 (Chl_669–672) was found. On increasing the density to 0·2–0·3 nm²/molecule, a conversion of C₄₆₀ and C₅₂₀ into C₅₀₀, was observed, and several more additional (probably more strongly aggregated) chlorophyll a forms appeared, with absorption bands at 672–733 nm. With excess carotene [(Chi)/(Car) = 1:3] the forms C₄₆₀, C₅₀₀, C₅₂₀ and Chl_669–672 were present even in the most dense films (0·2–0·3 nm²/molecule). The same was found with other carotenoids: if one of the pigments was in excess, aggregated forms of the other tended to disappear. In the transfer of energy from carotenoids to chlorophyll a, C₅₀₀ was found to be the main donor. In layers with a concentration ratio (Chl)/(Car) = 3:1, the efficiency of transfer was less than 10 per cent at the lowest density used (3·70 nm²/molecule); it increased to 50 per cent, as the density was increased to 0·20 nm²/molecule. When the relative concentration of the carotenoid was increased to (Chl)/(Car) = 1:1, the efficiency of energy transfer dropped to 25 per cent even at 0·20 nm²/molecule. It seems that the efficiency of energy transfer between carotene molecules (prior to its transfer to chlorophyll a) is low, and effective transfer occurs only between β-carotene and immediately adjacent chlorophyll a molecules.     

A RAPID AND FACILE CONVERSION OF PRIMARY AMIDES AND ALDOXIMES TO NITRILES AND KETOXIMES TO AMIDES WITH TRIPHENYLPHOSPHINE AND N-CHLOROSUCCINIMIDE

ABSTRACT

Primary amides and aldoximes are easily converted to their corresponding nitriles using a mixture of triphenylphosphine and N-chlorosuccinimide in dichloromethane at room temperature. The reaction of aldoximes occurs almost immediately and primary amides in 0.5?h by this method. By this procedure secondary amides are produced by Beckmann rearrangement of ketoximes.