痕量钒的阻抑动力学光度法测定

基于稀硫酸介质中痕量钒 (Ⅴ )对溴酸钾氧化 2 (5 溴 2 吡啶偶氮 ) 5 二乙氨基酚褪色反应的阻抑作用 ,建立了测定痕量钒 (Ⅴ )的动力学光度法。方法检出限为 0 .0 4 3μg·L- 1,线性范围为 0～ 4 .0 μg·L- 1。用于测定人发及茶叶样品中的痕量钒 (Ⅴ ) ,结果满意。     

等离子体质谱法测定地质样品中痕量稀土元素的基体效应及多原子离子干扰的校正研究

采用模拟地质样品中稀土元素间天然组成比的基体匹配校正标准溶液进行外标校正 ,有效地抑制了地质样品分析中的基体效应 ;以 1 1 5 In-1 0 3Rh双内标元素校正 ,监控和校正分析信号的短期和长期漂移 ;通过单个稀土元素及钡的氧化物、氢氧化物的测定计算出等效的干扰浓度 ,进而校正了稀土元素分析中多原子离子干扰 .建立了地质样品中痕量稀土元素测定中基体效应及多原子离子干扰的校正方法 ,通过对 5个标准参考物质的分析 ,定量测定限为 0 .0 0 9～ 0 .1 33μg· g- 1 ,RSD小于 5% .     

无滤共沉淀富集-等离子体原子发射光谱法测定痕量稀土元素

以编结反应器 (KR)作为反应场所,用NH3～NH4NO3缓冲溶液在线沉淀、富集,电感耦合等离子体原子发射光谱法(ICP-AES)检测稀土元素,系统地研究了稀土元素在线沉淀及溶解的最佳条件.实验结果表明:在80 ℃时,稀土离子与pH 9.0的NH3～NH4NO3缓冲溶液在线混合后经2 m KR富集120 s,用1 mol/L HNO3以1.0 mL/min流速洗脱时富集效果最好,富集倍数可达52～76倍,进样频率为10/h.同时考察了共存离子的干扰及其消除方法.方法的稀土元素的检出限为0.07～1.23 μg/L,精密度RSD在1.7%～4.3%之间(n=6),线性范围2～10 μg/L.应用于标准样品中痕量稀土元素的测定,其测定值与标准值吻合.     

微波消解样品-电感耦合等离子体质谱法测定植物灰分中微量元素

应用电感耦合等离子体质谱法(ICP-MS)同时测定植物灰分中21种微量元素和15种稀土元素.用微波消解样品,对微波消解植物灰分样品的条件进行了试验.其优选微波消解条件为:微波压力为2 MPa,消解时间为10 min,以硝酸、盐酸、氢氟酸、高氯酸(体积比为6比2比1比1)的混合酸消解样品,对0.100 0 g植物标准物质(GBW 07603)进行10次平行测定,微量元素测定结果的相对标准偏差(n=10)在0.87%～5.96%之间,稀土元素测定结果的相对标准偏差(n=10)在2.14%～8.00%之间.     

茶叶中稀土元素的萃取分离-ICP-AES法测定

采用1-苯基-3-甲基-4-苯甲酰基-5-吡唑酮(PMBP)苯溶液萃取分离-ICP-AES法同时测定茶叶中15种稀土元素,消除了基体的干扰,并对样品前处理方法、萃取分离条件进行了考查.方法回收率为: 92.3%～112%,相对标准偏差＜2.5%.在最佳工作条件下,测定了茶叶标准物质(GBW07605)中稀土元素,结果与标准值吻合.     

电感耦合等离子体质谱法测定硫化物单矿物中痕量稀土元素

硫化物单矿物基体复杂,在利用电感耦合等离子体质谱仪测定其中稀土元素时,基体效应干扰严重,为准确测定其中的稀土元素,必须对样品进行分离富集。采用硝酸-氢氟酸体系溶解样品,通过Fe(OH)_3共沉淀和阴离子交换树脂(AG1-X8)去除基体元素,利用电感耦合等离子体质谱法测定稀土元素。通过测定两种国家标准物质硫化物单矿物(GBW 07267,GBW07268,GBW07270)中稀土元素来验证该方法,方法检出限为0. 003(Tm)～0. 138(Ce) ng·g~(-1),加标回收率在91%～113%之间。     

中国稀土科技文献索引(2001)

6 37　 用ＤＨＥＤＣＭＰ在逆流色谱上分离镧系金属离子 ,金玉仁等 ,化学学报 ,2 0 0 0 ,5 8(6 ) ,6 92 .6 38　 等离子体质谱法测定地质样品中痕量稀土元素的基体效应及多原子离子干扰的校正研究 ,故圣虹等 ,高等学校化学学报 ,2 0 0 0 ,2 1(3) ,36 86 39　ＺｒＯ2 Ｙ2 Ｏ3 Ａｌ2 Ｏ3 系统的拉曼光源 ,谷晋骐等 ,天津大学学报 ,2 0 0 0 ,33(6 ) ,795 .6 4 0 　 红外法测定富镧混合稀土中磷和硫 ,王颖娥 ,理化检验 (化学分册 ) ,2 0 0 0 ,36 (5 ) ,2 2 8.6 4 1　 感耦等离子体质谱法直接测定碳酸盐中超痕量稀土元素 ,胡圣虹等 ,岩矿测试 ,…     

高分辨电感耦合等离子体质谱法测定镍基单晶高温合金中36种痕量元素

基于高分辨电感耦合等离子体质谱法(HR-ICP-MS)的质谱干扰消除技术,对镍基单晶高温合金中36种痕量元素检测的质谱条件、基体干扰、质谱干扰与同位素选择进行了研究。取样品0.100 0 g,用体积比为3∶1的盐酸-硝酸混合酸10 mL、氢氟酸1 mL溶解,用水定容至250 mL。通过复杂基体质谱干扰计算判定、共存元素干扰消除,确定了待测元素的同位素和分辨模式,将镍基单晶高温合金中痕量元素准确测定的元素种类确定为36种。采用标准加入法进行定量分析,36种痕量元素的检出限(3s)为0.004～6.000μg·L^-1。方法用于分析国际标准物质,得到的测定值与认定值基本一致。方法用于镍基单晶高温合金样品分析,36种痕量元素的检出量为0.000 001 0%～0.018%。     

电感耦合等离子体质谱测定富钴结壳中的稀土元素

采用封闭压力酸溶(HF+HNO3)消解样品,以Rh为内标,用电感耦合等离子体质谱测定富钴结壳中的稀土元素。用此方法对3个国家一级标准物质富钴结壳标样(GSMC-1,GSMC-2,GSMC-3)进行了多次测定,结果稀土元素的测定值与标准值相符,多次测定结果的相对标准偏差(RSD,n=5)在0.36%～4.0%之间,加标回收率为90%～106%。基于此方法,对6个富钴结壳样品进行了测定,显示富钴结壳样品中稀土元素的配分曲线与标准物质中稀土元素的配分模式一致。方法适用于富钴结壳样品的批量分析。     

超高效液相色谱法同时测定牙膏中5种植物源活性成分

建立了同时测定牙膏中丹皮酚(Pae)、麝香草酚(Thy)、和厚朴酚(Hon)、厚朴酚(Mag)、甘草次酸(Gly)5种植物源活性成分的超高效液相色谱方法。牙膏样品以90%甲醇为溶剂超声提取,离心取上清液过滤后进行分析,采用Waters ACQUITY UPLCHSS C_(18)(2. 1 mm×100 mm,1. 8μm)为分离柱,乙腈-0. 1%甲酸(pH 2. 8)为流动相,梯度洗脱,流速为0. 3 mL/min,二极管阵列检测器(PDA)的检测波长为275、250nm,外标法定量。结果表明,5种植物源活性成分在2～100 mg/L质量浓度范围内呈良好的线性关系,相关系数(r)均大于0. 999;检出限为0. 2～1. 0 mg/kg,定量下限为0. 8～3. 5 mg/kg;在4个加标水平下的平均回收率为90. 5%～99. 4%,相对标准偏差(RSD)为0. 7%～5. 1%。该法分析快速、重复性好、准确性好、灵敏度高,已应用于实际牙膏样品的测定。     

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。     

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.     

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.     

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^-。     

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.     

解决能源问题的新途径--光解水制氢的研究

面对日益枯竭的能源危机,氢能是一种洁净、最有前景的替代能源。目前在各种制氢的方法中光催化分解水制氢的研究最多,光解水过程中催化剂最关键,本文对利用太阳能光解水的途径、提高光催化反应效率以及光催化剂的开发研究进行了综述。     

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.     

黄酮化合物的合成研究进展

黄酮化合物是一类具有多种生物活性的天然产物,其经典的合成方法主要为查耳酮路线和β-丙二酮路线.近年来出现了许多新技术、新方法.本文介绍了2'-羟基查尔酮的氧化关环法、黄烷酮氧化法、改进的Baker-Venkataraman法及其他合成黄酮化合物的方法.     

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.