应用液-液色谱联用技术在线富集测定环境水中西维因和抗蚜威的残留量

为高效液相色谱法测定环境水样中残留的西维因和抗蚜威的含量,应用了液-液色谱联用技术,实现了在线富集、分离和检测。分析中用YWG-C18（10mm×4．6mm,10μm）和YWG-C18（150mm×4．6mm,10μm）依次作为富集柱和分离柱,以体积比45比55混合的甲醇与水的混合溶液作为流动相,其流速为1．0mL·min^-1。选定紫外光度检测的波长为228nm,试样溶液在富集柱上的流速为5．0mL·min^-1。此外,对渗漏体积等参素也作了试验,分析信号值与两农药的质量浓度在0．04～1．0μg·L^-1范围内呈线性关系。测得方法的检出限（S／N=3）为0．008μg·L^-1（西维因）和0．014μg·L^-1（抗蚜威）,回收试验的结果在93％～119％之间。还对日内和日间精密度进行了试验,测定西维因的日内精密度为1．3％～20．0％,日间精密度为2．39／6～22．2％,测定抗蚜威的日内精密度为2．0％～10．8％,日间精密度为2．2％～5．8％。     

火焰原子吸收光谱法测定水样中痕量镉——用流动注射-编结反应器对痕量镉作在线预富集

在火焰原子吸收光谱测定水样中痕量镉的方法中,提出了在流动注射-编结反应器对痕量镉离子作在线顸富集中用两次引入作为镉离子的配位体的吡咯烷二硫代氨基甲酸铵（APDC）溶液的模式。在此模式中,预先将APDC溶液涂覆在编结反应器的内壁上（这就是第一次引入APDC溶液）;第二次引入是将APDC溶液与试样溶液同时注入并在编结反应器中汇合。富集时样品溶液的流速为6．0mL·min^-1,富集时间为60s。按此方法操作镉的富集系数达到21,此值均高于单独用APDC溶液预涂覆编结反应器模式的富集系数（9）或单独用APDC溶液与试样溶液同时注入并汇合模式的富集系数（16）。方法的检出限（S／N=3）为0．32μg·L^-1,方法的进样频率为每小时36个样品,对20μg·L^-1镉标准溶液测定11次,测得方法的相对标准偏差为2．7％。应用此方法测定了几个水样中镉含量,并作回收试验,所得回收率在92．0%～99．0％之间。     

反相高效液相色谱法测定α-（2-氨基噻唑-4-基）-α[（叔-丁氧基羰基）异丙氧亚胺基]-乙酸

提出了制备头孢类抗生素的中间体α-（2-氨基噻唑-4-基）-α-[（叔-丁氧基羰基）异丙氧亚胺基]-乙酸（ATIA）的反相高效液相色谱测定方法,采用Spherigel^TM C18色谱柱（250mm×4．6mm,5μm）,以0．05g·L^-1四丁基溴化铵的甲醇-水（6＋4）溶液为流动相,流速为1mL·min^-1,柱温30℃,检测波长260nm,以外标法定量。在0．001～1．0mg范围内,ATIA的质量与峰面积呈线性关系,回归方程为A=31475．6m＋1786.7,相关系数为0．9997,以质量为0.06mg ATIA按方法测定6次,算得其相对标准偏差为3．7％,检出限（3S）为0．6μg,回收率的试验结果在98．8％～104．0％之间。     

持久性化学改进剂钨-铱用于电热原子吸收光谱法测定水和植物性食品中痕量镉

研究持久性化学改进剂钨-铱电热原子吸收光谱法测定水和植物性食品中痕量镉。用钨铱溶液（适宜用量为钨250μg,铱200μg）作为持久化学改进剂处理石墨平台并进行试验,与常规化学改进剂NH4H2PO4＋Mg（NO3）2比较,灵敏度高且背景信号低,且可用较低的原子化温度,可延长石墨管使用寿命;例如测镉时,可连续使用300-350次。分别测定水和植物性食品中痕量镉,相对标准偏差（n=5）在0．7％～3．3％之间,样品加标回收率在92．0％～111．3％之间,水和植物性食品中镉的检出限分别为0．036μg·L^-1和0．102μg·L^-1,特征质量为1．3pg。     

高效液相色谱-质谱联用法检测烤鳗中环丙沙星

烤鳗样品中的环丙沙星分两次用经稀甲酸（1＋99）酸化的乙腈提取。收集上层清液用乙腈定容为25.0mL,分取10．0mL,在40℃氮气吹干后溶于流动相溶液2．0mL中,加入正己烷2．0mL,萃取后取10．0μL下层溶液注入于高效液相色谱-质谱分析仪中。在HPLC分析中,用XBridge^TM Shied PR18柱（250mm×3．0mm,5μm）,以体积比15比15比70混合的甲醇、乙腈和稀甲酸（2＋998）组成的混合液为流动相,并采用荧光检测（FD）（激发波长275nm,发射波长445nm）。在MS分析中,采用选择离子监测（SIM）技术在电喷雾电离正离子[ESI（＋）]模式下检测,定量离子为m／z 331．9[M＋H]^＋。检测信号的峰面积与环丙沙星浓度之间在100．0～2500．0μg·L^-1（HPLC-FD法）和20．0～500．0μg·L^-1 MS-SIM-ESI（＋）法]范围内呈线性关系,其测定限（n=10）依次为50．0,10．0μg·kg^-1。在3个浓度水平上加入环丙沙星标准溶液进行精密度和回收试验,所得相对标准偏差（n=6）均小于6．5％,回收率在83．0%～99．0%之间。     

在硝酸钠存在下以三元缔合物形态浮选分离钯(Ⅱ)

在水溶液中,钯（Ⅱ）与硫氰酸铵、十六烷基三甲基溴化铵形成不溶于水的三元缔合物,在少量硝酸钠存在下,此三元缔合物沉淀浮于盐水相上层形成界面清晰的液-固两相,当溶液中十六烷基三甲基溴化铵、硫氰酸铵和硝酸钠的浓度分别为1×10^-3mol·L^-1,1．5×10^-2mol·L^-1,50g·L^-1,pH3.0时,钯（Ⅱ）被定量浮选。而铬（Ⅲ）、锰（Ⅱ）、镍（Ⅱ）、铝（Ⅲ）、钼（Ⅵ）、锌（Ⅱ）、铁（Ⅱ）在该体系中不被浮选,对合成水样和钯镍电镀废液中钯（Ⅱ）进行定量浮选分离测定。     

柱后衍生高效液相色谱法测定罗汉果甜甙中黄曲霉毒素B1

用柱后衍生高效液相色谱法测定了罗汉果甜甙中黄曲霉毒素B1（AFX B1）。用MYCOTOX^TM C18作为反相色谱柱,流动相为由甲醇、乙腈及水以22＋22＋56之比例混合的混合液。柱后衍生试剂为100mg·L^-1碘的水溶液,以荧光检测器在发射波长为365nm及激发波长为430nm条件下进行测定。在AFX B1的峰面积与质量浓度（mg·L^-1）之间呈线性关系,其回归方程为y=14．222x＋0．6253（r=0．998）,在三个浓度水平（5．1,40．8及102μg·kg^-1）上进行回收率及精密度试验,所得回收率在81．4％～94．2％之间,相对标准偏差（n=10）在2．1％～4．59／5之间。     

大口径石英毛细管柱气相色谱法测定黄豆甙原中有机溶剂残留量

用毛细管气相色谱法测定黄豆甙原中有机溶剂残留量。试样0．5g溶于含有内标正丁醇的二甲亚砜中,定容5mL。在优化条件下,用配有DB-17石英毛细管分离柱（0．54mm×30m,1．0μm）和火焰电离检测器的毛细管柱气相色谱仪测定黄豆甙原中残留的有机溶剂乙醇和N,N-二甲基甲酰胺（DMF）。乙醇和DMF的检出限分别是9．6pg和5．7ng;回归方程和相关系数分别为Y=0．04627＋0．65369X,r=0．9982和Y=0．02531＋0．35654X,r=0．9934;线性范围分别为50．4～718.9g·L^-1和9．8～137．2g·L^-1。     

苯基荧光酮沉淀捕集石墨炉原子吸收光谱法测定水样中痕量锗

以苯基荧光酮作沉淀剂,在pH2．0的条件下,直接沉淀捕集水样中痕量锗,并提出了石墨炉原子吸收光谱法测定水样中痕量锗的方法。采用涂钨石墨管,添加镧作基体改进剂消除测定锗时的基体干扰,提高测定的灵敏度。用一级标准物质对方法进行了验证,其检出限（S／N=3）为0．3μg·L^-1,样品加标回收率在95．2％～103．0％之间,相对标准偏差小于5％。     

吹扫-捕集/气相色谱-质谱联用法测定城市饮用水中挥发性卤代烃

采用吹扫-捕集器富集了城市饮用水样中11种挥发性卤代烃,经气相色谱法分离后用质谱法选择性离子监测模式进行定量测定,所测定的卤代烃,除含量相对较高的三氯甲烷外,线性范围在0．04～11．0μg·L^-1之间;检出限（S／N=3）均小于6pg·L^-1。对方法的回收率及精密度作了试验,测得回收率在85．6％～126．1％之间,相对标准偏差（n=7）在2．06％～3．87％之间。     

利用手持技术改进测定乙醇分子结构实验

利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

光谱仪测试范围的扩展

由于石化行业的生产需要，其材质的使用具有多样性和广泛性，经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识，根据光谱仪的测试能力及标样的采集，实现了一个或几个元素测量范围的扩展，并对其测量的影响因素进行了研究。     

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.     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.     

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.

     

物质分配系数的测定实验改进

实验教学目的是从解决实际问题出发,以实验技术训练和实验设计思想培养为目标。介绍了将单一的物质分配系数测定实验改进为综合实验,提高了实验效果及实验资源利用率。     

Calculation of enthalpies of hydrogenation of hydrocarbons

Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases.     

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。