毛细管气相色谱法测定中药材中多种拟除虫菊酯农药残留量

研究了气相色谱法测定中药材中多种拟除虫菊酯类残留量的分析方法。样品经正己烷．丙酮混合液[V（正己烷）：V（丙酮）=1：1]提取，氟罗里硅土层析柱净化，采用毛细管色谱柱分离，GC-ECD可同时测定8种拟除虫菊酯类农药残留量，回收率为76．6％～104．2％。     

气相色谱法测定荔枝中7种拟除虫菊酯类农药残留量

采用气相色谱法测定荔枝中联苯菊酯、甲氰菊酯、氯氟氰菊酯、氟氯氰菊酯、氯氰菊酯、氰戊菊酯和溴氰菊酯等7种拟除虫菊酯类农药的残留量。荔枝样品用丙酮-正己烷(1+1)混合液提取,所得提取液用活性炭柱和中性氧化铝柱的串联柱净化,用DB-35毛细管色谱柱分离,电子捕获检测器检测。7种拟除虫菊酯类农药的质量浓度均在0.05~0.8mg·L~(-1)内与其峰面积呈线性关系,方法的检出限(3S/N)在0.005~0.01mg·kg~(-1)之间。在0.05,0.1,0.2mg·kg~(-1)等3个浓度水平进行加标回收试验和精密度试验,回收率在81.0%~104%之间,测定值的相对标准偏差(n=6)在1.7%~5.1%之间。采用此法测定了荔枝样品中联苯菊酯的含量,所得测定值与行业标准方法测定结果相符。     

加速溶剂萃取-超高效液相色谱-串联质谱法测定茶叶中拟除虫菊酯类农药残留

建立了加速溶剂萃取（ASE）-超高效液相色谱（UPLC）-串联质谱法（MS/MS）测定茶叶中拟除虫菊酯类农药残留的方法。ASE萃取温度为80 ℃，萃取压力为10.34 MPa，以正己烷-丙酮（2∶1，v/v）为溶剂静态萃取5 min，循环一次。萃取液浓缩后经GCB/NH₂-Florisil柱净化，UPLC分离，MS/MS正离子扫描（ESI⁺）、多反应离子监测（MRM）模式进行分析，外标法定量。线性回归分析表明：10种拟除虫菊酯的浓度与其峰面积的线性关系显著，相关系数（r）均不小于0.9995，检出限（LOD）在0.5~5.0 μg/kg之间，定量限（LOQ）在1.6~16.6 μg/kg之间；在定量限、0.4 mg/kg以及最高残留限量（MRL，无MRL的加入1 mg/kg）3个水平进行添加回收试验（n=7），回收率为68.7%~103.8%，RSD为0.8%~13.2%。该方法前处理简单，耗时短，灵敏度和准确度高，可满足茶叶中痕量拟除虫菊酯类农药残留测定的要求。     

磷酸处理-气相色谱法测定含硫蔬菜中的多种有机氯及拟除虫菊酯类农药残留

建立了含硫蔬菜(青葱、洋葱、大蒜、蒜苔、韭菜等)中多种有机氯和拟除虫菊酯类农药残留的测定方法。采用10%磷酸处理含硫蔬菜,去除含硫化合物的干扰,再用1∶1的丙酮-正己烷提取,加入2%的硫酸钠溶液用正己烷进行液液分配,提取液用硅镁吸附剂层析柱净化,用气相色谱-电子俘获检测器检测。样品加标回收率在78.0%~97.8%之间,相对标准偏差在3.0%~9.6%之间。该方法的检出限为有机氯农药0.001 mg/kg,联苯菊酯、甲氰菊酯和三氟氯氰菊酯为0.002 mg/kg,其余五种拟除虫菊酯类农药0.005 mg/kg。     

加速溶剂萃取-液相色谱-串级质谱法测定近岸及河口沉积物中的拟除虫菊酯农药

建立了近岸及河口沉积物中拟除虫菊酯农药的加速溶剂萃取、液相色谱-串级质谱测定方法.以正己烷-丙酮(1∶ 1, V/V)为萃取剂,在萃取温度60℃、压力10.3 MPa下对目标农药进行静态萃取5 min,合并两次萃取的目标农药后浓缩;使用XDB-C18色谱柱、甲醇和2.5 mmol/L乙酸铵的水溶液为流动相进行分离; ESI正离子源、三重串级质谱及多反应监测模式(MRM)下进行测定.本方法的检出限(3σ)为0.08～0.8 μg/kg; 定量限(10σ)为0.5～2.5 μg/kg; 样品加标回收率在67.9%～97.3%之间; 相对标准偏差(RSD)为1.07%～8.61% (20.0 μg/kg,n=8),并应用本方法测定福建罗源湾沉积物样品中拟除虫菊酯类农药.本方法的灵敏度高,前处理简单、快速.     

中空纤维膜-液相微萃取-气相色谱/质谱法测定土壤中拟除虫菊酯类农药

采用中空纤维膜-液相微萃取-气相色谱/质谱法测定土壤中3种拟除虫菊酯类农药(联苯菊酯、氯氰菊酯、溴氰菊酯)。实验优化的样品制备和萃取条件为:土壤与水的质量比为1∶3,pH=4,超声时间为5 min,萃取剂为环己烷,萃取温度为25℃,搅拌速率为900 r/min,萃取时间为20 min。萃取后取1 mL萃取剂进行色谱分析。在此条件下,当采用SIM模式时,测得土壤中联苯菊酯、氯氰菊酯和溴氰菊酯的线性范围分别为0.01~25 mg/kg,0.5~50 mg/kg和0.5~50 mg/kg;检出限分别为0.003,0.020和0.040 mg/kg;相对标准偏差分别为4.3%,4.7%和8.6%。本方法可用于土壤中拟除虫菊酯类物质的快速测定。     

加速溶剂萃取-固相萃取净化-气相色谱-串联质谱法检测茶叶中9种拟除虫菊酯类农药残留

建立了加速溶剂萃取（ASE）-固相萃取净化（SPE）-气相色谱-串联质谱（GC-MS/MS）同时测定茶叶中9种拟除虫菊酯类农药残留的方法。ASE萃取溶剂为丙酮-正己烷（1：1,v/v）,萃取温度为100℃,萃取压力为10 MPa,加热时间为3 min,静态萃取时间为5 min,循环1次,冲洗体积为40%萃取池体积,氮气吹扫100 s。萃取结束后用Cleanert TPT固相萃取柱净化,净化液浓缩定容后,采用GC-MS/MS测定,外标法定量。9种拟除虫菊酯类农药在2~1000 μg/L范围内呈现良好的线性关系,相关系数（r²）均大于0.99,方法检出限为0.2~4.5 μg/kg,定量限为0.8~15.0 μg/kg。在绿茶、红茶空白基质中做加标回收试验,添加水平为0.02、0.1、0.4 mg/kg以及定量限水平,得到的平均回收率为69.87%~110.0%,相对标准偏差（RSD）为0.7%~11.2%。该方法背景干扰低、灵敏度高、重现性好、回收率稳定,适用于茶叶中拟除虫菊酯类农药残留量的检测。     

牛肉中7种拟除虫菊酯类农药残留的固相萃取-超高效液相色谱-串联质谱法测定

建立了牛肉组织中胺菊酯、氯氰菊酯、溴氰菊酯、氟胺氰菊酯、氰戊菊酯、氟氯苯氰菊酯、氯菊酯7种拟除虫菊酯类农药残留的超高效液相色谱-串联质谱测定方法,样品经乙腈提取后,吹干提取液,用正己烷溶解,氟罗里硅土固相萃取柱净化,经BEHC18色谱柱分离,以0.1%甲酸的甲醇溶液和0.1%乙酸铵溶液为流动相进行洗脱。电喷雾正离子模式(ESI+)电离,多反应监测模式(MRM)检测,外标法定量。结果表明,7种拟除虫菊酯类农药标准溶液在10～1000μg/L范围内呈良好线性,r2均大于0.998;方法检出限为5μg/kg,定量下限为10μg/kg;7种拟除虫菊酯农药在10～50μg/kg添加水平内的回收率为81%～116%,批内、批间RSD均小于15%。该方法具有简便快捷、灵敏度高、定性准确等优点,能满足食品安全检测有关法规的要求。     

茶叶中多种拟除虫菊酯类农药残留量的气相色谱-质谱测定

采用微量化学法和固相萃取技术，用丙酮/正己烷（1 1，V/V）萃取，活性炭和中性氧化铝小柱净化，用GC/MS可同时测定茶叶中6种拟除虫菊酯类农药的残留量。方法回收率在84.6%-115.1%之间，相对标准偏差为3%-7%，最低定量检出浓度在0.010-0.20mg/kg之间。该法快速、灵敏、准确，各项技术指标均衡足农残检测的要求。     

磁性固相萃取结合GC－MS检测烟叶中拟除虫菊酯类农药残留

该文基于β-环糊精（β-CD）的磁性复合材料（Fe3O4@SiO2@β-CD）建立了磁固相萃取结合气相色谱－质谱法同时检测烟草中联苯菊酯、甲氰菊酯、氟氯氰菊酯和溴氰菊酯4种拟除虫菊酯类农药残留的分析方法,对比了键合不同环糊精衍生物的复合材料（Fe3O4@SiO2@α-CD、Fe3O4@SiO2@β-CD和Fe3O4@SiO2@γ-CD）对4种拟除虫菊酯类农药的吸附性能,发现Fe3O4@SiO2@β-CD对4种目标分析物具有最高的萃取率。并采用扫描电镜、红外光谱、X射线衍射仪和微孔吸附材料分析测试仪对制备的磁性材料进行表征,考察了萃取时间、解吸时间、解吸溶剂、溶液pH值和盐离子浓度等对磁性复合材料萃取性能的影响,通过萃取容量实验研究经β-CD修饰前后的磁性复合材料对萃取性能的变化。结果显示,相比于未经修饰的Fe3O4和Fe3O4@SiO2,Fe3O4@SiO2@β-CD的萃取能力显著提升,该磁性复合材料Fe3O4@SiO2@β-CD可用于烟叶样品中4种拟除虫菊酯类农药的测定,线性范围为0.1～3.0 mg/kg,相关系数为0.998 1～0.999 8,检出限均为0.03 mg/kg,定量下限均为0.1 mg/kg,3个加标水平下的回收率为65.9%～107%,相对标准偏差（RSD,n = 3）为0.70%～12%。方法可用于烟叶中联苯菊酯、甲氰菊酯、氟氯氰菊酯和溴氰菊酯4种拟除虫菊酯类农药残留的检测。     

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。     

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。     

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.