分散固相萃取-高效液相色谱-串联质谱法同时测定畜禽肉中63种兽药残留

建立了分散固相萃取-高效液相色谱-串联质谱(dispersive-SPE-HPLC-MS/MS)同时测定畜禽肉中 β-内酰胺类、喹诺酮类、磺胺类、磺胺类增效剂和抗寄生虫类共5类63种兽药残留的新方法。样品经0.1 mol/L Na₂EDTA溶液及含1% (体积分数)乙酸的乙腈溶液涡旋提取,提取液经C18分散固相萃取净化后,用Poroshell EC-C18色谱柱(100 mm×2.1 mm, 2.4 μm)分离,在电喷雾离子源正离子模式下以动态多反应监测(DMRM)方式采集数据并做定性筛查和定量分析。63种药物在相应的浓度范围内线性关系良好,相关系数均大于0.99;不同畜禽肉(猪肉、牛肉及鸡肉)在3个不同添加水平下的平均回收率为62.2%~112.0%,相对标准偏差(RSD)为3.1%~16.3%,检出限(LOD, S/N≥3)和定量限(LOQ, S/N≥10)分别为0.1~3.0 μg/kg和0.5~10.0 μg/kg。该方法简便快速、灵敏可靠,适用于畜禽产品中兽药多残留的同时快速定性筛查和定量分析。     

高效液相色谱-串联质谱法同时测定供港生猪尿液中29种限用兽药残留

建立了高效液相色谱-串联质谱(HPLC-MS/MS)同时测定生猪尿液中喹诺酮类、磺胺类、磺胺增效剂、四环素类、林可胺类、大环内脂共29种限用兽药残留量的检测方法。试样经乙酸铵和EDTA-Na缓冲液提取,HLB固相萃取小柱净化后,HPLC-MS/MS进行测定,其中β-受体激动剂类用内标法定量,其余兽药用外标法定量。在电喷雾电离正离子模式下,以多反应监测(MRM)方式采集数据进行定性与定量分析。29种兽药在猪尿基质中标准曲线的线性系数(r)均大于0.99,3个不同加标水平下的平均回收率为58%~108%,日内相对标准偏差(RSD)为1.9%~18.9%,日间RSD为3.4%~20.9%;定量下限(LOQ,S/N≥10)为1.0~10.0μg/L。该方法经济、高效、可靠,可用于生猪屠宰前兽药多残留的快速检测。     

固相萃取/液相色谱-串联质谱法同时测定面膜类化妆品中非法添加的53种糖皮质激素

建立了固相萃取/液相色谱-串联质谱法(SPE/LC-MS/MS)同时测定面膜类化妆品中53种糖皮质激素的方法。样品经水分散后,加入甲醇涡旋提取,提取液用水稀释后,采用Cleanert PEP(60 mg,3 m L)固相萃取小柱净化。待测物经Waters CORTECS C18+(100 mm×2.1 mm,2.7μm)色谱柱分离,在电喷雾离子源的正离子模式下以动态多反应监测(DMRM)模式采集数据并作定性筛查和定量分析。53种药物在相应的浓度范围内线性关系良好,相关系数均大于0.99,在3个不同浓度加标水平下,平均回收率为66.8%~106.3%,相对标准偏差(RSD)为3.9%~13.2%,检出限(LOD,S/N≥3)和定量下限(LOQ,S/N≥10)分别为3μg/kg及10μg/kg。该方法操作简便、定性可靠、定量准确、灵敏度高,适用于化妆品中非法添加糖皮质激素的定性确证和准确定量。     

QuEChERS结合高效液相色谱-串联质谱法测定饲料中的18种β-兴奋剂

建立了饲料中克仑特罗、莱克多巴胺、喷布特罗、妥布特罗等18种β-兴奋剂的QuEChERS结合高效液相色谱-串联质谱的检测方法。饲料样品加水分散后经4%(v/v)氨水乙腈提取,加入25 mg十八烷基硅烷(C18)和50mg N-丙基乙二胺(PSA)吸附剂分散固相萃取净化后,以高效液相色谱-串联质谱进行定性和定量分析。采用Agilent Zorbax Eclipse XDB-C18(50 mm×4.6 mm,1.8μm)分析柱,以甲醇-0.1%(v/v)甲酸水溶液为流动相进行梯度洗脱,串联质谱在多反应监测(MRM)正离子模式下进行检测,基质外标法定量。结果表明,18种待测物在质量浓度为5~200μg/L范围内线性关系良好,相关系数为0.9912~0.9995;在0.05、0.1、0.5 mg/kg 3个浓度加标水平下,饲料中18种β-兴奋剂的平均回收率为78.4%~107.1%,相对标准偏差(RSD)为3.5%~12.3%,定量限(以信噪比≥10计)均为0.05 mg/kg。该方法准确、灵敏,前处理简单,可作为饲料中克仑特罗等18种β-兴奋剂筛选和确认的检测方法。     

超高效液相色谱-串联质谱法同时测定畜禽肉中磺胺类、喹诺酮类、硝基咪唑类兽药残留

建立了固相萃取-超高效液相色谱-串联质谱法同时测定畜禽肉中7种磺胺类、3种喹诺酮类及4种硝基咪唑类残留的方法。样品经乙腈提取,正己烷脱脂,MCX小柱净化后,由超高效液相色谱分离、三重四极杆质谱检测,基质外标法定量。14种兽药含量在1~50.0μg/L范围内线性关系良好,相关系数均大于0.994,加标回收率为75.2%~103.4%,检出限为0.1~0.5μg/kg,空白加标重复测定的相对标准偏差(n=6)为2.3%~12%。方法适用于畜禽肉中多种兽药残留的快速测定。     

超高效液相色谱-串联质谱测定饲料中镇静剂类和β-受体激素类药物残留

采用超高效液相色谱-串联质谱技术,建立了饲料中8种镇静剂类和15种β-受体激素类药物残留的分析检测方法。样品采用乙腈-1%(体积分数)三氯乙酸水溶液(7∶3,v/v)提取,目标物通过阳离子固相萃取柱净化,经Agilent Zorbax Eclipse Plus C_(18)色谱柱(100 mm×3.0 mm,1.8μm)分离,液相色谱-串联质谱进行检测,标准曲线内标法定量。结果表明:23种目标物在2.0~200.0μg/L内线性关系良好(r20.99)。在饲料样品基质中,目标化合物在5.0、10、50μg/kg 3个加标水平下的平均回收率为75.1%~102.4%,相对标准偏差(RSD)为4.3%~14.3%(n=6)。该方法净化效率高,适用范围广,可用于饲料中镇静剂类和β-受体激素类药物残留筛查和检测。     

磁性多壁碳纳米管固相萃取/高效液相色谱-串联质谱法测定蜂蜜中多组分兽药残留

建立了以磁性多壁碳纳米管为吸附剂的分散固相萃取/高效液相色谱-串联质谱检测方法,对蜂蜜中3大类44种兽药残留进行测定。样品经pH 4.0的Na2EDTA-Mcllvaine缓冲液提取,加入自制磁性多壁碳纳米管吸附目标物。目标物经10%氨水-甲醇洗脱后,液相色谱-串联质谱MRM模式进行定性定量分析。44种药物在1~40 ng/m L浓度范围内线性关系良好,相关系数均大于0.99;在3个不同浓度添加水平下,回收率为78.0%~105.1%,相对标准偏差(RSD)为1.2%~8.9%,检出限为0.2~2.0μg/kg。结果表明,该方法简单方便,易于操作,为蜂蜜中磺胺类、喹诺酮类以及硝基咪唑类兽药残留的测定提供了新途径。     

分散固相萃取-液相色谱-串联质谱法同时快速测定化妆品中81种糖皮质激素

建立了分散固相萃取-液相色谱-串联质谱同时快速测定化妆品中81种非法添加糖皮质激素(GCs)的分析方法。样品用水分散后加乙腈超声提取,经十八烷基键合硅胶(C18)和N-丙基乙二胺(PSA)净化,待测物选用具有多重色谱保留模式的Poroshell 120 PFP色谱柱(100 mm×2.1 mm,2.7μm)分离,以0.2%(v/v)乙酸水溶液-乙腈为流动相梯度洗脱,在电喷雾正离子模式下以动态多反应监测方式测定,内标法定量。81种待测物在各自的浓度范围内线性关系良好,相关系数均大于0.99,在3个不同的添加水平下,平均回收率为68.8%~105.3%,RSD为2.9%~13.1%(n=6),方法的检出限(S/N≥3)和定量限(S/N≥10)分别为0.002~0.006μg/g和0.005~0.020μg/g。筛查了137个化妆品样品,发现16个阳性样品,含量为16.9~158μg/g。结果表明,该法简便快速,灵敏可靠,适用于化妆品中81种GCs的同时快速定性定量筛查分析。     

分散固相萃取-同位素稀释-高效液相色谱-串联质谱法同时测定猪肉中26种β-受体激动剂

建立了分散固相萃取-同位素稀释-高效液相色谱-串联质谱(dSPE-ID-HPLC-MS/MS)同时测定猪肉中26种β-受体激动剂残留的方法。样品经β-葡萄糖醛苷酶/芳基硫酸酯酶水解12 h后,用高氯酸沉淀蛋白质,取上清液,调节pH值为9,用乙腈涡旋提取,分散固相萃取净化。选用具有混合分离模式的新型色谱柱Poroshell 120Phenyl-Hexyl(100 mm×2.1 mm,4.0μm)对待测物进行分离,在电喷雾离子(ESI)源正离子模式下以多反应监测(MRM)模式采集数据并做定性筛查和定量分析。26种待测物在相应的浓度范围内线性关系良好,相关系数均大于0.99,在3个不同浓度的添加水平下,平均回收率为65.3%~108.5%,相对标准偏差(RSD)为2.7%~13.3%,检出限(LOD,S/N=3)和定量限(LOQ,S/N=10)分别为0.03~0.1μg/kg及0.1~1.0μg/kg。该方法成本低廉、灵敏可靠,适用于同时对猪肉产品中26种β-受体激动剂残留进行定性和定量筛查。     

液相色谱-四极杆飞行时间质谱法筛查猪肉中5类26种药物残留

建立了同时筛查测定猪肉组织中氟喹诺酮类、磺胺类、有机磷类、β-激动剂类、四环素类5类26种药物残留的液相色谱-四极杆飞行时间质谱分析方法。试样采用QuEChERS前处理方法,样品经酸化乙腈-甲醇(1%乙酸,10%甲醇)提取。提取液以C18分散剂和正己烷净化,氮吹浓缩、定容后过滤膜上机检测。液相色谱以甲醇-水(0.1%甲酸)作为流动相梯度洗脱,C18色谱柱分离;高分辨质谱采用正离子模式检测,以二级质谱特征离子定性,以分子离子精确质量数提取色谱峰面积定量。结果表明26种药物的定量下限为0.4~10μg/kg;加标回收率为56.7%~106.2%,相对标准偏差(RSD)为7.7%~15.8%。方法操作简单、快速、高效,可作为猪肉中26种药物残留的快速筛查检测方法。     

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。     

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。     

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。