固相膜萃取-气相色谱法测定养殖用水中痕量有机磷农药

采用固相膜萃取-气相色谱法测定养殖用水中乐果、甲基对硫磷和马拉硫磷等3种有机磷农药的含量。水样经C18固相萃取膜萃取后,用丙酮和二氯甲烷洗脱。用SPB-608毛细管色谱柱分离,氮磷检测器检测。3种有机磷农药的质量浓度均在0.02~1.0μg·L-1范围内与其峰面积呈线性关系,方法的检出限(3S/N)在0.0025~0.004μg·L-1之间。以空白样品为基体进行加标回收试验,回收率在93.0%~111%之间,测定值的相对标准偏差(n=5)在0.13%~5.2%之间。     

固相萃取-衍生化-气相色谱-质谱法测定水中类固醇类雌激素

采用固相萃取-衍生化-气相色谱-质谱法同时测定水中4种类固醇类雌激素雌酮(E1)、17β-雌二醇(E2)、17α-乙炔基雌二醇(EE2)、雌三醇(E3)。样品经Oasis HLB固相萃取柱,以丙酮为溶剂进行洗脱后,采用吡啶、N-甲基-N-三甲基硅基三氟乙酰胺于40℃衍生化20min后,采用气相色谱-质谱仪分析。E1、E2、EE2和E3的线性范围分别为5.00~500μg·L-1和10.0~500μg·L-1,4种类固醇类雌激素的检出限(3S/N)在1.5~3.0μg·L-1之间,测定下限(10S/N)在5.0~10μg·L-1之间;方法用于实际水样的分析,加标回收率在86.8%~93.8%之间,测定值的相对标准偏差(n=7)在7.1%~11%之间。     

气相色谱-串联质谱法测定烟草中97种农药残留量

利用气相色谱-串联质谱法(GC-MS/MS)检测烟草中97种农药残留。样品以乙腈为溶剂经加速溶剂萃取(ASE),提取液用Carbon-NH2固相萃取小柱净化后,采用VF-5MS色谱柱分离,用电子轰击离子源-多反应监测模式(EI-MRM)检测。97种农药的质量浓度在20~1 000μg·L-1范围内与其峰面积呈线性关系,方法的测定下限(10S/N)在0.02~22.4μg·kg-1之间;在50,100,500μg·kg-1的加标水平下,测得回收率在67.4%~116%之间,测定值的相对标准偏差(n=6)在1.9%~14%之间。     

固相萃取-毛细管柱-气相色谱法测定水中11种有机磷农药

提出了固相萃取分离-毛细管柱-气相色谱法测定水中11种有机磷农药的方法。水样经Waters oasis HLB固相萃取小柱分离并净化,甲醇-丙酮(70+30)混合液洗脱。用Varian cp-sil24CB色谱柱(30m×0.25mm,0.25μm)分离,脉冲火焰光度检测器检测。11种有机磷农药的质量浓度均在5.00μg·L-1以内与其峰面积呈线性关系,测定下限(10S/N)在0.03~0.05μg·L-1之间。方法用于地表水样和饮用水样分析,加标回收率在65.7%~124%之间,测定值的相对标准偏差(n=6)在1.8%~9.9%之间。     

顶空固相微萃取-气相色谱-质谱法测定蔬菜及水果中15种农药残留量

应用顶空固相微萃取-气相色谱-质谱法测定蔬菜及水果中15种农药的残留量。样品用顶空-固相微萃取进行前处理。经优化的试验条件:1采用100μm聚二甲基硅氧烷萃取头;2离子浓度:样品匀浆液中含(w)30%氯化钠;3萃取温度为70℃±1℃;4萃取时间为30min。在气相色谱分离中用HP-5MS色谱柱,在质谱分析中采用全扫描和选择离子监测模式。15种农药的质量浓度均在0.05~1.0mg·L-1范围内与其峰面积呈线性关系,方法的检出限(3S/N)在0.02~0.10μg·kg-1之间。以2种果品作基体,在0.05,0.2,0.5mg·kg-1 3个浓度水平进行加标回收试验,测得回收率在71.0%~96.0%之间,测定值的相对标准偏差(n=5)在0.5%~9.8%之间。     

离子色谱法测定电子烟烟液中氨的含量

建立了测定电子烟烟液中的氨含量离子色谱法。样品经10 mol·L-1盐酸溶液萃取10 min后,采用Dionex Ion Pac CS16A阳离子交换柱分离,以MSA为淋洗液进梯度洗脱,用电化学检测器检测。氨的质量浓度在0.05~1.0 mg·L-1范围内与峰面积呈线性关系,检出限(3S/N)为0.035μg·g-1,测定下限(10S/N)为0.12μg·g-1。方法用于12种市售品牌电子烟烟液中氨的测定,加标回收率在93.2%~106%之间,测定值的相对标准偏差(n=5)小于4%。     

动态液相微萃取-气相色谱法测定水样中残留有机磷农药

应用动态液相微萃取与气相色谱联用技术测定了水样中3种有机磷农药(敌敌畏、甲基对硫磷、对硫磷).考察了萃取溶剂、溶剂体积、萃取次数、水样pH值以及离子强度对液相微萃取的影响.该方法甲基对硫磷、对硫磷的线性范围在30～70μg·L-1之间,敌敌畏的线性范围在40～70μg·L-1之间,回收率在84.9%～103.0%之间,相对标准偏差(n=7)在5.1%～9.4%之间,检出限(3S/N)为26.5～35.7μg·L-1.     

液液萃取-气相色谱-质谱法测定墨水中的16种多环芳烃

采用液液萃取-气相色谱-质谱法测定墨水中的16种多环芳烃。样品经二氯甲烷液液萃取后,使用固相萃取技术进行纯化。在气相色谱分离中用DB-5MS色谱柱为固定相,在质谱分析中采用选择离子监测模式。16种多环芳烃在一定的质量浓度范围内与其峰面积呈线性关系,方法的检出限(3S/N)在5.0~30μg·kg-1之间。以空白样品为基体进行加标回收试验,所得回收率在60.6%~116%之间,测定值的相对标准偏差(n=6)在1.5%~5.3%之间。     

微波辅助衍生-离子液体分散液液微萃取-高效液相色谱法测定发酵酒和饮料中甲醛

提出了微波辅助衍生-离子液体分散液液微萃取-高效液相色谱法测定发酵酒和饮料中的甲醛。以2,4-二硝基苯肼为衍生试剂,1-辛基-3-甲基咪唑六氟磷酸盐为提取剂,乙腈为分散剂,样品溶液在300 W的微波功率下辐照60s后离心,甲醛衍生物被萃取到离子液体中,用乙腈定容。以SB-C18色谱柱为分离柱,以水-甲醇(2+8)溶液为流动相进行洗脱,检测波长355nm。甲醛的质量浓度在1.00~100μg·L-1范围内与其峰面积呈线性关系,方法的检出限(3S/N)为0.16μg·L-1,测定下限(10S/N)为0.53μg·L-1。对啤酒、葡萄酒、可乐和橙汁4个样品进行加标回收试验,回收率在92.5%~99.1%之间,测定值的相对标准偏差(n=5)在2.6%~7.8%之间。     

液液萃取-气相色谱-质谱联用技术测定废水中N-甲基甲酰苯胺、N-甲基苯胺和甲酰苯胺

建立了液液萃取-气相色谱-质谱(GC-MS)联用测定废水中N-甲基甲酰苯胺(NMF)、N-甲基苯胺(NMA)和甲酰苯胺(FA)的分析方法。考察了萃取溶剂、盐加入量和pH等影响萃取效果的参数。结果表明,当以二氯甲烷为萃取剂,将pH调至11.85,15%NaCl溶液加入量为1%(体积比)条件下,NMF、NMA和FA的萃取效果最佳。以N,N-二乙基苯胺(DEA)为内标,在GC-MS选择离子模式下测定NMF、NMA和FA,该方法对三种目标物的平均回收率为97.5%~101.0%,相对标准偏差为4.3%~6.3%(n=6),检测限(S/N=3)为0.0018~0.0023μg/L,测得某废水样品中NMF、NMA和FA的含量依次为0.94±0.08、0.14±0.02和0.12±0.02g/L。     

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.     

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^-。     

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.