电感耦合等离子体质谱法测定有机肥料中砷、镉、铅、铬、汞的含量

提出了用微波消解-电感耦合等离子体质谱法测定有机肥料中砷、镉、铅、铬、汞等5种元素的方法。有机肥料样品(0.200 0~0.500 0g)加入硝酸10mL和过氧化氢溶液1mL,按程序升温微波消解,将消解液蒸发至2mL,用硝酸(1+99)溶液定容至50mL。用电感耦合等离子体质谱法测定上述样液中的砷、镉、铅、铬、汞等元素。各元素的检出限(3.3s/k)为0.015~0.040mg·kg~(-1),测定值的相对标准偏差(n=6)均小于5.0%。按标准加入法进行回收试验,测得回收率在98.0%~101%之间。     

离子交换分离-石墨炉原子吸收光谱法测定酵母抽提物中铅和镉

酵母抽提物样品(1.000g)经硝酸(20mL)消解并蒸干后加水(10mL),调整其酸度至pH 4.0。溶液通过D401离子交换树脂分离,用0.002 5mol·L~(-1)硝酸溶液(pH 2.6)淋洗交换柱后,用0.2mol·L~(-1)硝酸溶液洗脱吸附于树脂上的铅(Ⅱ)和镉(Ⅱ)。将洗脱液蒸至近干,用水定容至10mL。用石墨炉原子吸收光谱法测定其中铅、镉的含量,两者的线性范围依次为50~350,3~15pg,检出限(3s)依次为5.0,0.3pg。对3个实样按所提出方法进行分析,并用标准加入法计算方法的回收率为84.0%~115%,测定值的相对标准偏差(n=8)为1.8%~12%。     

火焰原子吸收光谱法测定海木耳中3种重金属

采用火焰原子吸收光谱法(FAAS)测定了海木耳中3种重金属(铜、铅和镉)。将海木耳样品去柄后剪碎并在烘箱中烘干至恒重,称取干燥样品1.0000g,分次用硝酸-高氯酸(9+1)混合酸10mL消解至溶解完全,定容至10mL,用FAAS按选定的仪器工作条件测定其中的铜、铅和镉量。对同一样品的上述3元素作5次平行测定,测定值的相对标准偏差依次为2.0%,3.2%及2.5%。用标准加入法测得方法的回收率为95.4%(铜),95.3%(铅)及103.0%(镉)。在测定结果中除铜量外,铅量及镉量均分别超过国家标准规定允许量的34.3倍和13.9倍。     

分散液液微萃取-分光光度法测定食用菌中镉的含量北大核心CSCD

取经清洗、粉碎并烘干的样品0.500 0g,用硝酸5mL及过氧化氢3mL,按程序升温模式微波消解。消解液于沸水浴中蒸发至约1mL,用水定容至50mL。取此溶液5.00mL依次加入0.2g·L^(-1) 5-Br-PADAP溶液2.0mL,氨性缓冲溶液(pH 9.0)3.0mL及100g·L^(-1) Triton X-114溶液3.0mL,加水定容至25mL,摇匀,使Cd^(2+)生成络合物,10min后加入辛醇1.0mL,涡旋混合1min,离心5min,吸出下层溶液,取出上层红色有机层,用乙醇定容至3mL,于540nm处用1cm比色皿测得其吸光度。镉的质量浓度在10.00mg·L^(-1)以内与吸光度呈线性关系,检出限(3s)为0.05mg·L^(-1)。加标回收率为93.3%~103%,测定值的相对标准偏差(n=6)小于5.0%。     

分散液液微萃取-分光光度法测定食用菌中镉的含量

取经清洗、粉碎并烘干的样品0.500 0g,用硝酸5mL及过氧化氢3mL,按程序升温模式微波消解。消解液于沸水浴中蒸发至约1mL,用水定容至50mL。取此溶液5.00mL依次加入0.2g·L~(-1) 5-Br-PADAP溶液2.0mL,氨性缓冲溶液(pH 9.0)3.0mL及100g·L~(-1) Triton X-114溶液3.0mL,加水定容至25mL,摇匀,使Cd~(2+)生成络合物,10min后加入辛醇1.0mL,涡旋混合1min,离心5min,吸出下层溶液,取出上层红色有机层,用乙醇定容至3mL,于540nm处用1cm比色皿测得其吸光度。镉的质量浓度在10.00mg·L~(-1)以内与吸光度呈线性关系,检出限(3s)为0.05mg·L~(-1)。加标回收率为93.3%~103%,测定值的相对标准偏差(n=6)小于5.0%。     

电感耦合等离子体质谱法测定纳米铜粉中6种微量元素北大核心CSCD

纳米铜粉样品(0.5000g)用8mol·L^(-1)硝酸溶液20mL溶解,用水定容至100mL,从上述溶液中分取10.0mL用0.3mol·L^(-1)硝酸溶液定容至50 mL。采用电感耦合等离子体质谱法测定样品溶液中钴、银、锑、锡、钡、铅等6种微量元素。以115In和205 Tl作为内标对测定的基体效应进行了校正,采用测定元素同位素以消除和减少质谱干扰。6种元素的检出限(3s)为0.002~0.074μg·L^(-1)。加标回收率为94.0%~103%,测定值的相对标准偏差(n=11)均小于5.0%。     

电感耦合等离子体质谱法测定纳米铜粉中6种微量元素

纳米铜粉样品(0.5000g)用8mol·L~(-1)硝酸溶液20mL溶解,用水定容至100mL,从上述溶液中分取10.0mL用0.3mol·L~(-1)硝酸溶液定容至50 mL。采用电感耦合等离子体质谱法测定样品溶液中钴、银、锑、锡、钡、铅等6种微量元素。以115In和205 Tl作为内标对测定的基体效应进行了校正,采用测定元素同位素以消除和减少质谱干扰。6种元素的检出限(3s)为0.002~0.074μg·L~(-1)。加标回收率为94.0%~103%,测定值的相对标准偏差(n=11)均小于5.0%。     

微波消解-原子吸收光谱法测定粮谷中铅、铜、镉、镁、锰、铁

用微波消解法进行样品消解,原子吸收光谱法测定了小麦粉国家标准物质中铅、铜、镉、镁、锰、铁6种元素的含量.其中镁、锰、铁用火焰原子化法,铅、铜、镉用石墨炉原子化法,方法的相对标准偏差分别为1.43%(镁),4.72%(镉),5.20%(锰),6.04%(铜),13.8%(铁)及18.7%(铅),检出限分别为0.001(铅及铜),0.000 1(镉),0.01(锰)及O.02(镁和CA)mg·kg-1.     

石墨消解-动态反应池模式-电感耦合等离子体质谱法测定烟用香精和料液中5种元素的含量北大核心CSCD

将烟用香精和料液样品0.3 g(精确至0.001 g)置于全自动石墨消解仪消解罐中,分3次加入消解液(共计10 mL硝酸、1 mL高氯酸),在170℃的最高消解温度下,样品消解完全.所得溶液用水定容至50 mL,采用电感耦合等离子体质谱法(ICP-MS)测定其中砷、铅、镉、铬、镍等元素的含量.以铟为内标,铬、镉、镍、铅、砷元素的测量同位素分别为^(52)Cr、^(111)Cd、^(60)Ni、^(208)Pb、^(75)As,使用动态反应池(DRC)模式消除了铬、砷元素的质谱干扰,铬、镉、镍、铅等元素的测定选择氦气碰撞模式,砷元素的测定选择氢气反应模式.结果表明,5种元素的质量浓度在一定范围内与各元素与内标计数值的比值呈线性关系,检出限(3s)为0.016~0.035 mg·kg^(-1).按标准加入法进行回收试验,各元素回收率为91.5%~111%,相对标准偏差(n=6)为0.28%~3.1%.方法用于10个烟用香精和料液样品的分析,铬、砷、镍的检出量分别为0.019~0.061 mg·kg^(-1),0.039~0.061 mg·kg^(-1)和0.022~0.031 mg·kg^(-1),镉和铅未检出.     

电感耦合等离子体原子发射光谱法测定明矾石矿中11种元素的含量

取明矾石矿样品(0.200 0g),在铂坩埚中与由碳酸钠和四硼酸钠(质量比2∶1)组成的助溶剂1.000 0g充分混匀,并在950℃熔融30min。取出冷却,用盐酸(1+9)溶液50mL浸出熔块,将所得溶液定容至100mL。此溶液用于电感耦合等离子体原子发射光谱法测定铁、钙、镁、铜、钛、铅、铬、镓的含量。另从此溶液中分取5.0mL,用水定容为100mL,供测定含量较高的钾、铝、硅。分别试验了用基体匹配法和加入2mg·L~(-1)钇作内标的基体匹配法这两种条件以抑制基体效应。结果表明:在上述两种条件下测得的结果,其准确度相近;但后一条件下测得结果的精密度高于前一种条件。     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

Study of hydration of two cements of different strengths

Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, M_o, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700^oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.     

Acid hydrolysis of carboxymethylcellulose of low degree of substitution

Cotton cellulose was swollen in a sodium hydroxide solution and carboxymethylated by a two-bath method for different periods of time for each process. The kinetics of acid hydrolysis and the crystallinity of the swollen and carboxymethylated samples were measured. The proportion of broken bonds, rate constants for hydrolysis, and permeability of cellulose to hydrolyzing agents were calculated. The susceptibility of glycosidic linkages to acid hydrolysis was improved by carboxymethylation more than by swelling in alkali. The increased accessibility of carboxymethylcellulose to acid was regarded as a consequence of increased intra-and intercrystalline swelling and of the glycosidic bonds' weakness caused by the electron-attracting carboxymethyl group on the C-6 position.     

恶臭嗅辨实验室建设探讨

针对恶臭测试的环境影响问题,提出了解决的实例方案,并对方案的要点及优缺点进行讨论,此方案在实际操作中具有较好的效果。     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

Estimation of Kinetic Parameters of Thermal Oxidation of Ilmenite

The aim of the presented work was the investigation of thermal oxidation of ilmenite in static air atmosphere. The investigations were carried out by use of a derivatograph (MOM, Hungary). The changes of crystallographic structure of investigated samples were identified by X-ray diffractometry on Philips PW-1710 diffractometer. In temperature above 500°C appears structure of hematite Fe₂O₃. On the basis of the thermogravimetric measurements, the contracting area and contracting volume models were found as the best fitting experimental data. This revised version was published online in August 2006 with corrections to the Cover Date.