超高效液相色谱-串联质谱法测定畜产品中6种青霉素类药物残留

采用超高效液相色谱-串联质谱法快速测定牛肉和牛奶中青霉素类药物残留。样品以磷酸盐缓冲溶液提取、乙酸锌沉淀蛋白、正己烷脱脂,然后经HLB固相萃取柱净化后,采用超高效液相色谱-串联质谱分离检测,外标法定量。6种青霉素的线性范围均在25.0μg·L-1以内,检出限(3S/N)为2μg·kg-1,测定下限(10S/N)为5μg·kg-1。加标回收率在77.0%~99.8%之间,测定值的相对标准偏差(n=6)在3.7%~13%之间。     

高效液相色谱-质谱法测定尿液中痕量雷公藤春碱

提出了尿液中雷公藤春碱的高效液相色谱-质谱测定方法。尿液样品经Waters Oasis(MCX固相萃取小柱富集、净化后,以Zorbax Eclipse SB C18反相色谱柱(4.6 mm×250 mm,5μm)为分离柱,以乙酸盐缓冲溶液-乙腈(40+60)为流动相,采用正离子模式大气压化学电离源,在选择离子监测模式下进行检测,雷公藤春碱的定量离子质荷比(m/z)为874.4。线性范围为0.2~50.0μg·L-1,检出限(3S/N)为0.07μg·L-1,测定下限(10S/N)为0.2μg·L-1。回收率在86.0%~92.0%之间,日内(n=6)和日间(n=15)相对标准偏差分别小于7.5%和10.5%。     

气相色谱-串联质谱法快速测定果蔬中20种有机磷农药的残留量

采用气相色谱-串联质谱法快速测定果蔬中20种有机磷农药的残留量。果蔬样品以乙腈提取,以氨基/石墨化碳作为吸附剂。在气相色谱分离中用HP-5MS毛细管色谱柱为固定相,在质谱分析中采用全扫描和多反应监测模式。20种有机磷农药的质量分数均在5~2 000μg·kg~(-1)内与其对应的峰面积呈线性关系,方法的检出限(3S/N)为0.11~1.02μg·kg~(-1),测定下限(10S/N)为0.26~3.51μg·kg~(-1)。以空白样品为基体进行加标回收试验,所得回收率为83.8%~107%,测定值的相对标准偏差(n=6)为2.1%~14%。     

高效液相色谱-串联质谱法测定农产品中矮壮素残留量

提出了农产品中矮壮素的高效液相色谱-串联质谱(HPLC-MS/MS)分析方法。样品经甲醇-水(1+1)溶液提取,正己烷液液萃取后,采用阳离子交换固相萃取柱净化。所得净化液以阳离子交换树脂与C18混合填料色谱柱为固定相,以含0.1%(体积分数)乙酸的乙腈-10mmol·L-1乙酸铵(1+1)溶液为流动相进行等度洗脱,采用电喷雾正离子源,多反应监测模式检测,同位素内标法定量。矮壮素的线性范围为1.0~100μg·L-1,检出限(3S/N)为5μg·kg-1,测定下限(10S/N)为10μg·kg-1。矮壮素在10,100,500μg·kg-1等3个加标水平的回收率为90.5%~98.5%之间,测定值的相对标准偏差(n=6)在0.99%~2.2%之间。     

加速溶剂萃取-气相色谱-串联质谱法检测烟草中生物碱

建立了气相色谱-串联质谱(GC-MS/MS)法同时测定烟草中烟碱、降烟碱、麦斯明、假木贼碱和新烟草碱等5种生物碱的分析方法。以甲醇和Na OH溶液混合溶剂作提取溶剂,样品经加速溶剂萃取(ASE)萃取后,利用GC-MS/M S的多反应监测模式(M RM)测定,内标法定量。5种生物碱的检出限在0.06~0.12μg/m L之间,加标回收率介于88.9%~106.8%,相对标准偏差(RSD)均小于6%。方法适用于批量烟草样品中生物碱的快速测定。     

超声萃取-气相色谱-质谱法测定卷烟主流烟气中的6种挥发酚

采用气相色谱-质谱法测定卷烟主流烟气中的苯酚、对甲酚、间甲酚、邻甲酚、对苯二酚和间苯二酚等6种挥发酚的含量。用剑桥滤片在标准抽吸条件下采集5支卷烟烟气粒相物,用甲醇超声萃取10min。所得萃取液用DB-624毛细管色谱柱(30m×0.25mm,1.4μm)为固定相进行分离,在质谱分析中采用全扫描和选择离子监测模式。以苯酚-D_5为内标物。方法的检出限(3S/N)在10~16ng·支~(-1)之间,测定下限(10S/N)在28~40ng·支~(-1)之间。加标回收率在84.6%~99.1%之间,测定值的相对标准偏差(n=6)在2.1%~6.4%之间。     

顶空-气相色谱-串联质谱法测定水中苯甲醚的含量

采用顶空-气相色谱-串联质谱法测定水中苯甲醚的含量。取10mL水样和氯化钠3g加入于顶空瓶中,于70℃平衡15min,搅拌速率为95r·min~(-1)。气相色谱中采用Rxi-5Sil毛细管色谱柱,质谱中采用电子轰击离子源和多反应监测模式。苯甲醚的质量浓度在0.005~0.1μg·L~(-1)范围内呈线性,检出限(3S/N)为0.001μg·L~(-1),加标回收率在73.7%~92.2%之间,测定值的相对标准偏差(n=6)为3.7%~8.2%。     

QuEChERS-超高效液相色谱-串联质谱法快速测定鱼肉中22种磺胺类药物残留

结合QuEChERS前处理技术,提出了测定鱼肉中22种磺胺类残留的超高效液相色谱-串联质谱法。样品用含0.1%(体积分数,下同)甲酸的乙腈溶液提取后,经QuEChERS试剂盒净化。净化液在Agilent ZORBAX Eclipse Plus C18色谱柱上分离,以0.1%甲酸溶液-甲醇为流动相进行梯度洗脱。采用电喷雾正离子源及计划式多反应监测模式进行测定,以内标法定量。磺胺硝苯、磺胺、磺胺喹噁啉的线性范围为0.5~50μg·L-1,检出限(3S/N)为0.5μg·L-1;其他19种磺胺类兽药的线性范围为0.1~50μg·L-1,检出限(3S/N)为0.1μg·L-1。加标回收率在78.2%~118%之间,测定值的相对标准偏差(n=6)在3.4%~19%之间。方法用于鱼肉中多种磺胺类药物残留的快速测定,结果与标准方法测定结果一致。     

凝胶色谱净化-气相色谱-质谱法同时测定烧烤肉制品中19种多环芳烃

提出了凝胶色谱净化-气相色谱-质谱法同时测定烧烤肉中19种多环芳烃含量的方法。烧烤肉样品经正己烷-二氯甲烷(1+1)溶液超声提取30min后,上清液经凝胶色谱净化,所得净化液用HP-5MS色谱柱分离,全扫描模式和选择离子监测模式测定。19种多环芳烃的峰面积与质量浓度在5~200μg·L-1范围内呈线性关系,检出限(3S/N)在0.1~0.5μg·kg-1之间。在20,40,80μg·kg-1 3个浓度水平进行加标回收试验,19种多环芳烃的回收率在58.0%~122%之间,相对标准偏差(n=6)小于21.5%。     

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。     

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。     

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。     

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.     

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.     

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。     

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.     

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.