电感耦合等离子体质谱法测定磷矿石中锰、铜、铅、锌、铬、镉

建立了HNO3-HCl O4-HF混合酸溶样,电感耦合等离子体质谱法同时测定磷矿石中的锰、铜、铅、锌、铬和镉等6个微量重金属元素的有效方法.试验中对仪器的最佳工作参数进行了优化,选择适当的同位素,并用铑作内标元素,有效地抑制了分析信号的漂移.在选定的条件下,对样品进行了精密度和回收率试验,方法相对标准偏差(RSD,n=9)为0.99%~1.98%,加标回收率为98.0%~102.0%.     

双道原子荧光光谱法测定蔬菜中的砷和汞

采用湿法消解蔬菜样品,用AFS-230E型双道原子荧光光度计测定蔬菜中的As和Hg重金属含量。在最佳实验条件下,As和Hg元素的工作曲线相关系数(r)分别为0.999 2和0.999 6,检出限分别为0.011 9和0.013 9μg/L,加标回收率分别为:91.6%~101.5%和89.8%~97.3%,相对标准偏差(RSD,n=7)分别为1.4%和0.52%,方法可供各地测定各类蔬菜中As和Hg等重金属元素含量作参考。     

气相色谱法测定铁皮石斛、浙贝母和人参中嘧菌酯残留

本文建立了铁皮石斛、浙贝母和人参三种中药材中嘧菌酯的残留检测方法。样品采用乙腈提取,二氯甲烷液-液萃取,弗罗里硅土-中性氧化铝-活性炭柱层析净化,乙酸乙酯定容,气相色谱-电子捕获检测器(GC-ECD)检测,基质外标法定量。结果表明:在0.01~1.0mg/L范围内,不同基质中嘧菌酯的峰面积与其质量浓度间呈良好线性关系,相关系数均大于0.999;在0.01、0.1和0.5mg/kg的添加水平下,嘧菌酯在3种中药材基质中的平均回收率为85.0%~94.9%,日内相对标准偏差(RSD)均小于5.2%(n=5),日间RSD均小于6.7%(n=15);其在铁皮石斛、浙贝母和人参基质中的检出限(LOD)为0.002~0.004mg/kg,定量限(LOQ)均为0.01mg/kg。方法的准确度和精密度均满足残留分析要求,适用于铁皮石斛、浙贝母和人参中嘧菌酯的检测。     

氢还原重量法测定氯化钯产品中的钯

系统研究了氢还原重量法测定氯化钯产品中钯含量的测定条件,考察了杂质元素对钯分析结果的误差影响。结果表明:于选定条件下,测定59.78%~60.03%含量的钯,极差、标准偏差(SD)、相对标准偏差(RSD,n=22)和重复性限(r)分别为±0.01%,0.0047%~0.0050%,0.0079%~0.0083%和0.009%~0.014%,样品加标回收率达到99.98%,钯分析结果准确、可靠、精密度高。     

电感耦合等离子体质谱法(ICP-MS)测定土壤中的重金属元素

采用电感耦合等离子体质谱法(ICP-MS)测定了国家标准土壤样品中的部分重金属元素(Cd,Cu,Pb,Zn,Cr,Ni,Mo)的含量,其测定值与推荐值相符,准确度符合国家标准要求。各元素方法的检出限满足要求,相对标准偏差(RSD)介于0.91%~4.3%,加标回收率介于94%~106%。方法简便快速,结果准确,可以运用于大批量地质样品中的部分重金属元素含量的同时测定。     

微波样品消解-电感耦合等离子体质谱法测定北部湾海产品中重金属的含量

北部湾海产品样品在硝酸-过氧化氢(4+3)混合液中经微波消解处理,采用电感耦合等离子体质谱法测定样品溶液中7种重金属(铬、铜、砷、镉、锑、汞、铅)的含量。采用内标法消除基体的影响。方法的检出限(3s)在0.018~0.23μg·L-1之间。按方法分析海虾样品做精密度试验,上述7元素测定值的相对标准偏差(n=6)在1.4%~8.8%之间。方法用于黄鱼(GBW 08573)和扇贝(GBW 10024)两个国家标准物质中重金属含量的测定,测定值与认定值相符。     

氢化物发生-原子荧光光谱法测定铬矿中铅

建立了一种过氧化钠熔融、盐酸酸化提取,氢化物发生-原子荧光光谱法定量测定铬矿中铅的方法。试验优化了样品熔样温度、熔样时间、熔剂用量及上机测试条件,检验了共存元素的干扰。实验结果表明,方法精密度(RSD, n=11)为1.47%～3.68%,加标回收率为96%~105%,检出限为0.2μg/g。方法用于铬矿中元素铅的测定,精密度高、准确性好,检出限低,满足铬矿中铅元素的定量检测要求。     

电感耦合等离子体质谱(ICP-MS)法同时测定荞麦秸秆中的8种重金属元素

基于硝酸-盐酸-氢氟酸消解体系,建立了马弗炉-微波消解-电感耦合离子体质谱(ICP-MS)法同时测定荞麦秸秆中的Cr、Cu、Ag、Mn、Fe、As、Ni、Pb等重金属含量测定方法。在微波消解的过程中,分别考察5种不同组合的混合酸体系及两种消解方法对荞麦秸秆中8种重金属测试结果的影响。实验结果表明,浓硝酸-浓盐酸-氢氟酸(6∶2∶2)混酸体系和马弗炉-微波消解样品前处理优于其他方法。在优化条件下,8种重金属加标回收率为91.2%~102%,相对标准偏差(RSD,n=5)为0.22%~4.7%,检出限为0.18~9.41μg/L。方法操作简便、快速、准确,结果可靠,能同时测定荞麦秸秆中8种重金属元素。     

自动电位滴定法测定工业碳酸钠中氯化钠含量

采用自动电位滴定法,用硝酸银标准溶液作为滴定剂,测定工业碳酸钠中氯化钠含量。方法检出限为0.13mg/L,不同含量氯化钠样品加标回收率为99.7%~100.3%,相对标准偏差(n=5)为0.17%~2.0%,方法简单、快速,精密度和准确度高,适合大批量快速分析样品。     

电感耦合等离子体原子发射光谱法测定大气颗粒物中的12种重金属元素含量

采用电感耦合等离子体原子发射光谱法测定大气颗粒物中12种重金属元素的含量。用石英滤膜收集大气颗粒物中的12种重金属元素,分别采用电热板和微波消解法处理样膜。电热板消解时,12种重金属元素的检出限在0.001~0.07 mg·L~(-1)之间,测定下限在0.004~0.28mg·L~(-1)之间,测定值的相对标准偏差(n=6)在0.78%~5.8%之间。微波消解时,12种重金属元素的检出限在0.001~0.05mg·L~(-1)之间,测定下限在0.004~0.20mg·L~(-1)之间,测定值的相对标准偏差(n=6)在0.46%~4.5%之间。应用该方法分析了标准样品,所得测定值与认定值相符。     

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.     

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.     

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.     

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。     

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.     

Mechanism of action of base-catalyzed oxygenation of phenol derivatives

Cyclopropyl derivative of 2,6-di-tert-butylphenol is synthesized as a probe to investigate the mechanism of base-catalyzed autooxidation of phenol derivatives. Our study indicates that one electron reduction of molecular oxygen from phenolate gives phenoxyl radical 3, a key intermediate of autooxidation. The coupling of phenoxyl radical and superoxide radical gives peroxylate anion 4 and produces the final epoxy alcohol adduct 6.     

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^-。