室温离子液体对多种有机溶剂残留的同时顶空分析

利用1-乙基-3-甲基咪唑四氟硼酸盐([Emim][BF4])为顶空溶剂的顶空气相色谱法(HS-GC)快速、准确地分析了药物中的丙酮、四氢呋喃、二氧六环、吡啶及甲苯等有机溶剂残留。采用ZB-1毛细管柱(60m×0.53mm,5.0μm),程序升温方式,顶空瓶平衡温度100℃,平衡时间20min。待测溶剂在所考察的浓度范围内具有良好的线性,平均回收率为90.1%～96.9%;RSD均小于4.2%;检出限分别为0.05,0.07,0.28,0.31及0.04mg/L。室温离子液体作为溶剂使得方法的灵敏度有所提高。     

基于离子液体的静态顶空气相色谱技术

综述了近年来离子液体作为顶空溶剂静态顶空气相色谱法或气相色谱质谱法联用技术在挥发性成分的样品前处理中的研究进展,主要是其在药物、食品、空气等样品中的挥发性成分包括有机溶剂残留、活性成分、基因毒性杂质、农药残留等的顶空分析研究与应用和有机溶剂残留顶空分析的理论研究,并探讨了离子液体作为顶空溶剂的静态顶空气相色谱技术存在的问题和未来发展方向。     

顶空气相色谱法同时测定托比司他中的6种残留溶剂

采用顶空气相色谱技术,建立了同时测定托比司他中6种残留溶剂的方法。考察了不同固定相对分离效果的影响,优化了平衡加热时间影响以及制样溶剂。在优化的实验条件下,采用Rtx-200型聚三氟丙基甲基硅氧烷为固定相的色谱柱(30 m ×0.25 mm ×1μm)分离、氢火焰离子化检测器检测、外标法定量的分析方案,实现了甲醇、乙醇、二氯甲烷、乙酸乙酯、1,4-二氧六环和吡啶6种残留溶剂的同时分离与测定。6种溶剂在各自的线性范围内线性关系良好,线性相关系数( R2)均大于0.998,定量限分别为甲醇0.006%、乙醇0.005%、二氯甲烷0.012%、乙酸乙酯0.0025%、1,4-二氧六环0.0076%、吡啶0.004%。在3个添加水平下,6种残留溶剂的加标回收率在92.3%~100.3%之间,相对标准偏差为0.3%~3.6%。实际样品分析结果表明,本方法简单、快速、分离效果好,可用于托比司他中6种残留溶剂的检测。     

顶空-气质联用法对醋酸纤维滤棒中溶剂残留的测定

利用顶空-气质联用仪(HS/GC-MS)建立了一种同时测定醋酸纤维滤棒中溶剂残留的测定方法.利用顶空气相色谱技术,用选择离子模式对醋酸纤维滤棒中溶剂残留进行了定量分析.分析结果表明,方法线性关系良好,相关系数均大于0.998 0,检出限为0.010 4~0.157 8 mg/kg.9种溶剂残留的平均回收率为90.3%~102.2%,相对平均偏差小于10%.方法适用于醋酸纤维滤棒溶剂残留的测定且高效、准确、简便.     

离子液体/水混合溶剂促进芳醛与罗丹宁的缩合反应

在室温条件下, 离子液体1-正丁基-3-甲基咪唑四氟硼酸盐([bmim]BF₄)与水组成的混合溶剂能有效催化一系列芳醛与罗丹宁反应, 以80%～93%的产率生成相应的5-芳亚甲基-2,4-噻唑二酮. 离子液体[bmim]BF₄催化活性高, 反应在10～120 min内完成. 实验结果表明该法反应条件温和、产率高、反应时间短、后处理简单、离子液体可重复使用.     

顶空/气相色谱-质谱法同时测定报纸中14种溶剂残留

建立了同时测定报纸中14种溶剂残留量的顶空/气相色谱-质谱分析法。采用顶空气相色谱技术,以毛细管柱(Agilent HP-INNOWAX,60 m×250μm,0.25μm)分离,选择离子监测模式(SIM)下进行质谱检测。在优化的顶空/气相色谱-质谱分析条件下,14种溶剂残留在2~20μg范围内线性关系良好,相关系数均不小于0.995;方法的定量下限(S/N=10)均小于0.01 mg/m2。加标水平为3.97~16.28μg时,待测物的平均回收率为86.6%~101.8%,相对标准偏差(RSD,n=6)均不高于6.8%。本方法快速、准确、灵敏,适用于报纸中溶剂残留的测定。     

静态顶空/气相色谱-质谱联用快速测定茶粉中残留溶剂

在基质改性剂H2O,平衡温度55℃,进样针温度60℃,传输线温度65℃,平衡加热时间30min,顶空气体进样量0.2mL等顶空取样条件下,建立了静态顶空取样,气-质联用技术快速测定茶粉中残留溶剂乙酸乙酯、氯仿的方法。结果表明该方法简单快速、准确度高、重复性好。     

室温离子液体在分离分析中的应用

室温离子液体是指室温或接近室温下全部由离子组成的有机液体物质,具有不挥发,不易燃,溶解范围大,对空气和热稳定等特点,作为一种“可设计”型的环境相对友好溶剂,已被成功应用于分离分析领域中。本文重点综述了离子液体近年来在毛细管电泳、液相色谱及气相色谱中的应用进展,也对离子液体在质谱和光谱中的应用作了介绍。     

酰胺类杂环烯酮缩胺的合成

建立了以杂环烯酮缩胺(HKAs)为原料,用芳基异氰酸酯为酰化剂,实现杂环烯酮缩胺选择性酰化.通过该区域选择性反应简洁、快速地合成了一系具有潜在药理活性的酰胺类杂环烯酮缩胺化合物的方法.该方法以六元或七元环杂环烯酮缩胺1~2与芳基异氰酸酯4在1,4-二氧六环溶剂中室温下合成杂环烯酮缩胺α-碳选择性酰基化产物5~6,产率90%~98%;而五元环杂环烯酮缩胺3与芳基异氰酸酯4在1,4-二氧六环溶剂中碳酸铯催化室温下合成杂环烯酮缩胺选择性氮酰基化产物7,产率78%~93%.     

混合离子液体-静态顶空气相色谱法测定转基因大豆油中六六六与滴滴涕残留量

基于离子液体无蒸气压、高沸点、溶解能力优良及混合离子液体同时具有亲水和疏水性的特点,建立了以［Bmim］PF6∶［Bmim］BF4为1∶2的混合离子液体作为顶空溶剂,平衡加压静态顶空进样测定转基因大豆油中六六六、滴滴涕残留量的方法。对离子液体的种类、配比、用量,以及顶空平衡温度、顶空平衡时间、顶空进样时间等条件进行了优化。研究结果表明：在最佳条件下,方法的线性范围为5~100 μg/L,相关系数为0.990 5~0.999 6,检出限为1.4~15.2 μg/kg,定量下限为4.7~48.6 μg/kg,回收率为72.3%~104.1 %,相对标准偏差为0.6%~7.8%。本方法快速、准确,且避免了复杂的前处理,是顶空进样检测农残的新方法。     

顶空液相微萃取-气相色谱法测定盐酸雷尼替丁中二氯甲烷和三氯甲烷的残留量

采用顶空液相微萃取与气相色谱联用技术测定雷尼替丁中二氯甲烷和三氯甲烷的残留量。自制了萃取液保护装置。考察了萃取溶剂的种类、萃取时间、萃取温度、萃取液的体积对二氯甲烷和三氯甲烷萃取效果的影响。以正十三烷为萃取剂,在60 ℃下萃取30 min,萃取液滴体积2 μL。二氯甲烷含量在1～10 μg/g范围内与色谱峰高呈线性关系,相关系数(r2)为0.9733;三氯甲烷含量在1～10 μg/g范围内与色谱峰高呈线性关系,r2为0.9724。二氯甲烷和三氯甲烷的最低检出限分别为0.0273 μg/g和0.0410 μg/g,加标回收率分别为93.6%～102%和98.1%～103%。方法简便易行,测定结果准确。     

顶空-气相色谱-质谱联用法同时测定紫外光固化胶印油墨中27种溶剂残留

建立了同时测定紫外光固化（UV）胶印油墨中27种溶剂残留（挥发性有机化合物,VOCs）的顶空-气相色谱-质谱联用（HS-GC-MS）法。将UV胶印油墨样品模拟印刷制成一定面积、厚度的试样,在紫外灯下烘烤1 min,经80℃、45 min静态顶空后,通过VOC专用毛细管柱分离和质谱检测,外标法定量。27种VOCs均呈现良好的线性关系,相关系数（R²）均≥0.9950;方法的检出限（LODs,S/N=3）为0.001~0.310 mg/m²,定量限（LOQs,S/N=10）为0.003~0.920 mg/m²;样品的平均加标回收率为80%~108%,相对标准偏差（RSD）<6%（n=6）。该方法制样便捷,灵敏度高,精密度好,准确度高,将其应用于实际UV胶印油墨样品的检测,取得了良好效果。     

Solvent and temperature effects on the reduction and amination reactions of electrophiles by lithium dialkylaminoborohydrides

The influence of temperature and solvent effects on the reduction and amination mechanisms of iodomethane by lithium N,N-diisopropylaminoborohydride (iPr-LAB) was examined in varying concentrations of THF and dioxane. The reactions of benzyl chloride and trimethylsilyl chloride with iPr-LAB in THF were also studied. The amination of iodomethane is favored over reduction at low and room temperatures in pure THF and with increasing the amount of dioxane in THF. At higher temperatures, the reduction reaction appears to compete with the amination. In dioxane solvent, however, iodomethane yields exclusively the amination product regardless of temperature. On the other hand, reduction by iPr-LAB to the aminoborane is the only product observed in THF when benzyl chloride and trimethylsilyl chloride are used. To understand the solvent effects on the product distribution, ab initio and density functional theory (DFT) calculations were used to examine the mechanisms of reduction and amination of chloromethane and bromomethane by lithium dimethylaminoborohydride (LAB) in THF and dioxane. The results of these calculations show that the relative reaction barrier heights are significantly affected by the nature of the coordinated solvent molecule and thus lend support to the experimental observations.     

Extraction of trace organic pollutants from aqueous samples by a single drop method

Summary A single drop extraction method for isolation of trace organic pollutants from aqueous samples is described. The optimisation of extraction parameters such as drop volume, temperature, time and solvent type, on the extraction efficiency was investigated. This technique involves use of small amounts of organic solvent (2μL) in a conventional GC syringe. The analytical performance of this technique is presented for the determination of trichlorobenzene and trichloromethane. Suitable precision of extraction was obtained with RSD values in the range of 2.5–5.2%. Presented at Balaton Symposium on High Performance Separation Methods, Siófok Hungary, September 1–3, 1999     

Temperature dependence of the viscosity of dilute poly(β-naphthyl methacrylate) solutions

The temperature dependence of the actual viscosity of dilute poly(β-naphthyl methacrylate) solutions was described by an Arrhenius expression according to Moore's treatment. The apparent activation energy of flow was found to be lower for solutions in benzene, toluene and tetralin than for solvent. In dioxane, a good solvent, the activation energy was nearly constant and close to that for the solvent. The pre-exponential terms were, in all cases, higher for solutions than for the solvents. The decrease in activation energy and increase in pre-exponential term are largely dependent on solvent power: the maximum effect is found in the poorest solvent. This behaviour is discussed in connection with the temperature dependence of the Mark-Houwink and of the Fox-Flory constants obtained from intrinsic viscosity data: the differences in the activation energy of flow and in the pre-exponential term between the solvent and the solutions are related to variation of coil expansion with temperature.     

顶空-气相色谱法测定水中三氯甲烷和四氯化碳方法的改进

改进了顶空-气相色谱法测定水中三氯甲烷和四氯化碳的方法,对平衡温度和平衡时间进行了优化,对不同溶剂配制的标准使用液和不同方法制作的工作曲线对测定结果的影响进行了比较.试验结果表明,样品最佳平衡温度和时间分别为50℃和35 min.采用甲醇代替标准中规定的纯水配制标准使用液,采用微量进样针取样到预先密封的顶空瓶中,三氯甲...     

凝胶渗透色谱用聚丙烯酸标样的制备

以二氧六环为良溶剂,石油醚为沉淀剂,通过等温沉淀分级,制得8种不同分子量的聚丙烯酸标样。 采用渐近校正法测定了它们的峰值分子量和分子量分布,建立了GPC校正曲线,并将其用于聚丙烯酸试样的测定。 结果表明,由渐进校正法测得的粘均分子量与粘度法测得的分子量之间的平均相对误差为7%,由渐进校正法测得的数均分子量与端基滴定法测得分子量之间的平均相对误差为9%。 将上述标样用于实际聚丙烯酸试样的测定,测得试样的粘均分子量与粘度法测定结果之间平均相对误差小于10%,优于以聚乙二醇为标样测定的平均相对误差（30%左右）。 本标样可用于具有与聚丙烯酸相似结构的阴离子聚电解质分子量分布的测定。     

Characterization of groundwater contaminants using dynamic thermal stripping and adsorption/thermal desorption-GC-MS

Summary Alternate methods to the time consuming solvent extraction technique used in the characterization of groundwater contaminants were sought to reduce the analysis time and allow for automation. By adsorbing (ADS) groundwater samples on a quartz tube filled with graphitized charcoal (Carbotrap, Carbotrap C) and thermally desorbing it in a Envirochem Unacon 810 unit directly interfaced with a GC-MSD, it was possible to detect the major groundwater contaminants originating from several types of industrial landfills. Compounds such as aniline, dioxane, and phenols were measured simultaneously with minimal sample preparation. The results were compared to those obtained by dynamic thermal stripping (DTS) followed by GC-MS. These methods are much more cost effective than solvent extraction since they require only a few minutes of the analyst's time for the introduction of the sample. ADS was superior to DTS and solvent extraction for the analysis of water soluble compounds which are poorly extracted into solvents. DTS provided cleaner chromatograms and allowed for lower detection limit than ADS. The two techniques are therefore complementary.     

紫外分光光度计检测十二烷基苯磺酸钠鉴别潲水油的方法研究

建立了潲水油中十二烷基苯磺酸钠(SDBS)的检测方法,样品经高纯水提取、三氯甲烷萃取、亚甲蓝显色后,以紫外分光光度法进行测定。考察了提取温度、提取时间等因素的影响。实验结果表明,水对食用油中SDBS的最佳提取时间为2 h,温度为50℃,检测波长为645 nm。方法检出限(LOD)为0.1μg/kg。加标量分别为1.0、5.0、10.0、20.0μg/kg时的回收率为94%～96%,相对标准偏差(RSD)均小于5%。5组实际样品的检测结果显示,潲水油中SDBS的残留量平均值为19.19μg/kg,优质食用油中SDBS的平均含量为0.35μg/kg。潲水油中SDBS的含量有很大差别,但总体均高于优质食用油中的含量,方法可用于潲水油和食用植物油的鉴别。     

Thermodynamics of the solution equilibria of 3-hydroxypyridine and pyridoxine in water-dioxane mixtures

The thermodynamics of tautomeric and microscopic ionization equilibrium constants of 3-hydroxypyridine and pyridoxine have been determined in waterdioxane mixtures (0–70% weight fraction in dioxane) ranging from 10°C to 50°C. Generally, for both types of processes, the entropic contributions to the Gibbs energy predominate and this tendency increase concomitantly with the dioxane content in the media. The thermodynamic parameters are consistent with the corresponding values obtained from macroscopic ionization processes. An equation for the equilibrium constant K as a function of temperature and a solvent characteristic parameter is proposed to predict the K values throughout the whole range of the temperature and solvent compositions studied.