多面体低聚八(二苯砜基)硅倍半氧烷合成优化及磺酰化机理研究

以笼型低聚八苯基硅倍半氧烷(OPS)为原料,AlCl3为催化剂,苯磺酰氯为磺酰化试剂,在二氯甲烷溶液中反应72h,合成了笼型八(二苯砜基)硅倍半氧烷(ODPSS).该方法合成过程简单稳定,产率高.通过FTIR、MALDI-TOF MS、1H NMR、13C NMR、29Si NMR和元素分析对产物进行了表征,证明OPS已完全转化为ODPSS.通过改变溶剂、催化剂、反应时间和各反应物物质的量之比,优化了反应条件,分析了反应机理,建立了该体系下OPS的磺酰化反应机理模型.     

Synthesis and Characterization of Ferrocenyl Substituted Styryl Octasilsesquioxane

4-(2-Ferrocenylethenyl)-phenyl-POSS Fc-CH=CH-C6H6-(C5H9)7Si8O12 (FEPS, Fc: ferrocene), containing metal and C=C double bond, was firstly synthesized as a mixture of E/Z isomers by the Wittig reaction. The chemical structure of FEPS was characterized by FTIR, 1H-, 13Cand 29Si-NMR.     

聚有机硅倍半氧烷的合成及其在涂层材料中的应用

聚有机硅倍半氧烷由于具有优异的力学、电学、光学性能,近年来被广泛应用作涂层材料以提高其热稳定性、耐腐蚀性、耐磨性、耐刮伤性、绝缘性等。介绍了聚有机硅倍半氧烷的合成方法及其在涂层材料中的应用。     

多面体低聚八硝基苯基硅倍半氧烷纯度分析

使用高效液相色谱-电喷雾四级杆飞行时间质谱(HPLC-ESI-Q-TOF MS)联用技术对八硝基苯基硅倍半氧烷(ONPS)纯度进行分析, 从而判定ONPS产物峰及杂质峰的位置, 根据ONPS峰和杂质峰的面积比计算ONPS的纯度. 通过改变HPLC的洗脱梯度和测试时间, 将ONPS产物中的杂质峰完全分开, 测得硝基苯基硅倍半氧烷(NPS)质量分数为97.55%, 其中ONPS的纯度约为92.42%, 产物中含有九硝基八苯基硅倍半氧烷(9-NPS)约5.13%, 其它杂质含量约为2.45%. 通过对ONPS高效液相色谱图峰形和同分异构体极性情况分析, 进一步证明ONPS分子中硝基取代发生于对位和间位. 使用超高效液相色谱(UPLC)对ONPS进行分析, 以更高的分离效率验证了HPLC的结果. 该方法可作为ONPS纯度的分析方法.     

环二硅氮烷-聚硅氧烷共聚物高温气相色谱固定相的研究

含苯基的环二硅氮烷聚硅氧烷共聚物(TMCDPS)主链上含有刚性结构,具有良好的耐热性能。将此材料用作毛细管气相色谱固定相,考察该固定相的柱效、极性、热稳定性,并对石蜡、聚乙烯裂解产物、原油等样品进行色谱分析。实验结果表明:该固定相有着良好的分离效果,属于中等极性固定相,其最为突出的特点就是在聚硅氧烷主链上引入大分子基团,使得其耐温性能大大提高,温度达到400℃时,柱流失量依然不高。     

气相色谱法测定痕量氟方法的研究

气相色谱法测定有机硅化合物中的痕量氟是60年代末发展起来的,1967年Bock和Semmer^[1]用三乙基氯硅烷等有机硅化合物萃取,用半饱和NaHCO₃反萃测定氟,并建议可用GC法直接测定三乙基氟硅烷,1968年Fressen等^[2]用气相色谱法测定氟,近20年来,气相色谱法测定氟在环境监测、卫生防疫等方面得到应用^[3,4]。     

聚苯乙烯包夹硅基高效液相色谱固定相的研究

用包夹聚合法制备出一种新型的聚苯乙烯包夹硅基高效液相色谱固定相并进行了固定相的表征。对色谱行为的研究表明此固定相在分离碱性、强极性溶质时有良好的分离性能,固定相在较高ｐＨ的洗脱液中有较好的稳定性。     

热脱附-气相色谱-质谱法检测聚氨酯防水涂料中化学物质向无规共聚聚丙烯管的迁移情况

选择3种涉水无规共聚聚丙烯(PPR)管材和3种聚氨酯防水涂料作为迁移试验样品,并确定了迁移试验的方案和试验用试件的制备方法。将所制备的试件置于烘箱中,在不同的温度下进行周期为14d的迁移试验。在试验到达14d时,立即抽取管外气体和管内气体各0.5mL进行气相色谱-质谱法(GC-MS)分析;随即将预置在管内的吸附管取出进行热脱附-质谱分析;然后用乙酸乙酯20mL反复冲洗PPR管,收集全部冲洗液进行GC-MS分析;最后,将冲洗过的PPR管沿内径中心切开,分别用乙醇和丙酮擦拭内外表面后置于环境舱中1d后,采集舱内气体并进行热脱附-质谱分析。在上述各测试中,选择聚氨酯防水涂料中在50℃时就发生迁移且含量较高、分离较完全的3种甲苯类化合物(3-乙基甲苯、2-乙基甲苯和1,3,5-三甲苯)作为迁移参照物(MRPU)。试验结果表明:①检测的温度条件是决定材料之间迁移的决定性因素。当温度不小于50℃时,聚氨酯防水涂料中的化学成分能迁移至PPR管内;当温度不大于40℃时,则未发现有迁移发生,由此可确定聚氨酯防水涂料中化学组分发生迁移的临界温度为40～50℃。②3种PPR管在相同温度下迁移的结果完全相同,由此可知PPR管本身对迁移的影响很小,或者可说其影响远小于温度的影响。③如果PPR管经保护层处理,则聚氨酯防水涂料中的化学组分不能迁移至管内。     

气相色谱-质谱联用法对三乙基硼合成反应副产物的研究

利用气相色谱/质谱联用技术对三乙基硼合成反应的产物进行了定性研究.进样量为5 μL,以HP-5毛细管柱(30.0 m×250 μm, 0.25 μm)为气相色谱柱,在柱温90℃、气化室温度120℃、载气为氦气、流量为0.8 mL/min的条件下,三乙基硼合成产物得到了很好分离.通过对该反应产物进行人工质谱解析,并结合计算机谱库检索,鉴定出三乙基硼合成反应的5种副产物.其中二乙基环硼氧烷在其它文献中未见报道.通过对反应过程的研究,讨论了多种副产物产生的机理,佐证了副产物的结构,为三乙基硼及其类似物的研究奠定了基础.     

Theory of Fast Capillary Gas Chromatography Part 4: Column Performance vs.Liquid Film Thickness

The negative effect of the liquid stationary phase film thickness on the column efficiency is strongest for peaks with retention factors, k, in the vicinity of k = 0.3–0.4 and rapidly diminishes with the departure of k from that region. Additionally, at the high pressure drop required for fast analysis of complex mixtures, the negative effect of the same film thickness diminishes with the increase in column length, regardless of the k values. In practice, it is recommended to ignore the film thickness and optimize the columns as thin film ones regardless of their actual film thickness. Accounting for the film thickness results only in a modest improvement in the resolution for a few affected peaks – those with k = 0.3–0.4. However, this improvement comes at the cost of a substantial increase in analysis time, and should be used only as the action of the last resort.     

Capillary Column Inlet System for the Gas Chromatography of Biological Samples

Abstract

A glass injection system consisting of a packed precolumn and gasphase splitter has been developed for the introduction of derivatized biological samples on glass capillary columns. The precolumn provides complete sample evaporation before the splitter zone, traps contaminating nonvolatiles, and prevents decomposition or adsorption of components. In addition, a carrier gas control system is described that permits stable and repeatable adjustment of split ratio and capillary inlet pressure.

The linearity of the splitter has been established using a hydrocarbon mixture covering the range of methylene unit (MU) values in which the steroid derivatives are eluted.     

Large Volume Injection in Fast Gas Chromatography with On‐Column Injector

In this work a fast gas chromatography set‐up with on‐column injection was optimized and evaluated with a model mixture of C₈–C₂₈ n‐alkanes. Usual injection volumes when using narrow‐bore (e. g., 0.1 mm i.d.) analytical columns are ca. 0.1 μL. The presented configuration allows introduction of 10–30‐fold larger sample volumes without any distortion of peak shapes. In the set‐up a normal‐bore retention gap (1 m×0.32 mm i. d.) was coupled to a narrow‐bore (4.8 m×0.1 mm i. d.×0.4 μm film thickness) analytical column using a low dead volume column connector. The effects of the experimental conditions such as inlet pressure, sample volume, initial injection temperature, and oven temperature on a peak focusing are discussed. H‐u curves for helium and hydrogen are used to compare their suitability for high speed gas chromatography and to show the dependence of separation efficiency on the carrier gas velocity at high inlet pressures. In the fast gas chromatography system a baseline separation of C₁₀–C₂₈ n‐alkanes was achieved in less than 3 minutes.     

水果中三唑酮残留量的气相色谱和气相色谱—质谱分析

水果中三唑酮残留用丙酮提取，经液－液分配净化，用气相色谱－电子捕获检测器测定，并用相色谱－质谱进行确证以ＨＰ－５大口径毛细管柱和ＨＰ－５ＭＳ毛细管柱为分离柱，选择出合适的色谱条件。三唑酮的分离效果良好。     

Fast Capillary Gas Chromatography: Comparison of Different Approaches

Savings in analysis time in capillary GC have always been an important issue for chromatographers since the introduction of capillary columns by Golay in 1958. In laboratories where gas chromatographic techniques are routinely applied as an analytical technique, every reduction of analysis time, without significant loss of resolution, can be translated into a higher sample throughput and hence reduce the laboratory operating costs. In this contribution, three different approaches for obtaining fast GC separations are investigated. First, a narrow-bore column is used under conventional GC operating conditions. Secondly, the same narrow-bore column is used under typical fast GC conditions. Here, a high oven temperature programming rate is used. The third approach uses a recent new development in GC instrumentation: Flash-2D-GC. Here the column is placed inside a metal tube, which is resistively heated. With this system, a temperature programming rate of 100°/s is possible. The results obtained with each of these three approaches are compared with results obtained on a column with conventional dimensions. This comparison takes retention times as well as plate numbers and resolution into consideration.     

Deactivation,coating and performance of nickel capillary columns for GLC

Electroformed nickel tubing was deactivated by chemical vapor deposition of silicon from silane gas and subsequent treatment with cyclooctamethyltetrasiloxane (D4). Standard activity tests performed on the uncoated tube and also on columns coated with crosslinked and uncrosslinked, nonpolar stationary phase, show that good quality flexible columns can be prepared from nickel tubing. The inner surface of the silicon coated tube was characterized by Auger depth profile analysis.     

Polymer-Coated Fibrous Packing Materials in Metal Capillary Gas Chromatography

Gas chromatography (GC) is one of the most versatile separation methods for volatile compounds, and a variety of polymeric materials as the stationary phases have been developed for various applications. In contrast to the successful applications and commercialization of the polymer-coated columns, the reports for the fibrous     

The Use of Non-Splitting Injection Techniques for Trace Analysis in Narrow-Bore Capillary Gas Chromatography

The use of hot splitless, cold splitless, and on-column injections for trace analysis in narrow-bore capillary GC is evaluated. Despite the low flow rates for the columns used, the required splitless times for splitless injections can be surprisingly short if liners with a small inside diameter are used. On-column injection can be applied by using an appropriate normal-bore precolumn coupled to the narrow-bore analytical column using a specially designed low dead volume column connector. The effects of the experimental conditions such as sample volume, injection temperature, and initial oven temperature on peak focusing and the discrimination and degradation behavior of the analytes are discussed. The possibilities to obtain sensitive and fast separations are illustrated by various applications.     

串联毛细管柱对甲基叔丁基醚产品及其杂质的色谱分析

采用非极性的OV-1柱及极性的FFAP柱串联而成的毛细管柱分析甲基叔丁基醚(MTBE)产品的全组成,该法能完全分离MTBE及其杂质组分,相对标准偏差小于3．5％。具有分离效果好、结果准确、操作简单等优点。     

Deactivation of fused silica capillary columns with phenylhydrosiloxanes

In this work, an investigation of new organosilicon hydride reagents with phenyl functional groups for deactivation and surface modification of fused silica capillary columns is described. Different reagents were tested for their ability to deactivate the fused silica surface, and actual critical surface tension measurements were made using the capillary rise method. The deactivation procedure required lower optimum temperatures than conventional methods. Deactivated capillaries and coated capillary columns were prepared and tested for reproducibility, efficiency, and surface inertness towards basic and acidic compounds at the low nanogram level.