气相色谱可调样量进样技术

(一)气相色谱可调样量进样装置 气样在较低压力(本实验为1大气压)时,其样品数量关系可用气体状态方程描述: PV=nRT (1) 气相色谱进样系统中,人们使P,TV,恒定,从而实现定量进样。应用方便,广为使用。 但是,在需要变量进样的情况下就出现了新的问题。有人使P,T恒定,改变进样管体积V,达到改变进样量之目的。确实见到有人备有几只不同体积V的进样管,可是实际切换时颇多麻烦。 本实验技术为实施方便计,使V,T恒定,采用调控进样压力P的办法,达到可调样量变量进样之目的。     

气相色谱法高效快速分析多种燃气组分

采用热导检测器,通过几种柱的组合,采用多维柱切换系统并自动完成阀的驱动和信号切换,实现性质不同的人工煤气和液化石油气主要成分一次进样自动分析,方法操作简便,分离效果好,灵敏度高,结果准确可靠。     

微流量液相色谱在线大体积进样的方法和专用装置

本发明涉及微分离系统的进样方法,具体地说是一种微流量液相色谱在线大体积进样的方法和专用装置。在微流量液相色谱分离系统的流路中,添加多流路分流切换装置,使得系统在进样和分离时,流动相可以从不同流路分流。样品利用在固定相上的保留,实现色谱系统的大体积进样。     

一种微流控芯片中大体积进样方法及专用芯片

本发明涉及微流控芯片系统的进样方法。在使用固定相的微流控芯片系统中,于芯片分离通道与流动相人口之间设置两个或两个以上的分流通道。通过控制其中流体的切换和截止,实现对微流控芯片系统的大体积进样。该方法适合于微流控芯片中电色谱、加压电色谱和液相色谱模式下的大体积进样。该方法的优点为：可实现微流控芯片中大体积样品的上样;克服了系统中的梯度延迟效应,     

通过柱切换技术与高效液相色谱联用的限进性柱对盐酸贝那普利的在线富集性能

以自制的限进性填料柱为预处理富集柱,Luna C₁₈柱为分析柱,通过柱切换技术将限进性填料柱与高效液相色谱联用(RAM-HPLC),研究了盐酸贝那普利的在线富集效果。考察了进样体积与峰面积、系统总压力的关系,以及常规进样与大体积进样的差别。当进样体积在100 μL以内时,峰面积随进样体积的增加而增加;当进样体积大于80 μL时,系统总压力变化明显。考虑对整个系统的保护,选择80 μL作为最大进样体积。同一浓度的样品进样20 μL与进样80 μL所得峰面积之间的线性关系良好。RAM柱对盐酸贝那普利具有良好的富集作用,能够有效提高HPLC的灵敏度,而且具有简单、经济的特点。     

在线分析脱丙烷塔顶中气体组分的气相色谱柱系统研究

 根据生产要求 ,对裂解装置中高压和低压脱丙烷塔顶中工艺气的气相色谱在线监控柱切换流程进行了研究。通过 3个进样器的二次异步进样 ,结合前吹、反吹等技术 ,应用 7根柱子 ,成功地在 6min内实现了对 C2 ' S、丙烷、丙烯、丙炔、丙二烯及 C4' S的在线分离分析。现场应用表明 ,研制的柱切换系统满足工艺监控要求。     

用二维色谱技术测定聚合反应气体组成

介绍一种无阀切换的二维气相色谱分析方法。采用两根不同性质的色谱柱并联连接，样品分别经两根色谱柱分离后汇合在一起进入同一检测器。一次进样可同时测定Ｈ２、Ｏ２、Ｎ２及Ｃ１～Ｃ３的组分。     

高效液相色谱柱切换系统中系统峰受色谱条件的影响及其干扰的避免

在建立茶碱高效液相色谱(HPLC)柱切换方法测定的预试验过程中,发现在不进样及不进任何空白样的情况下,空切换后,在所收集的色谱图上有一些正峰或负峰存在,文献中称这些正峰或负峰为系统峰^[1]。这些峰的存在在一定程度上对被测样品峰产生干扰。对于因样品直接进样产生的系统峰,国外有较多报道^[2,3],而关于HPLC柱切换系统     

热裂解乙烯气的在线多维色谱分析

]本文介绍了一种新的热裂解乙烯气在线多维色谱分析系统。采用一次进样、自动阀切换技术、TCD和FID双检测器检测、归一化方法定量,用一根氧化铝填充玻璃毛细管柱和三根填充柱,约75分钟完成水蒸汽热裂解气样中包括碳戊烯的全组成分析。整个系统具有分析结果重复性好、准确度高、操作方便、提供的组成信息全面等特点。     

烟道气组成的快速测定

将Porapak柱、Chromosorb P柱及5A分子筛柱串联后再并联，构成一个无阀切换的二维色谱，用于测定烟道气组成；一次进样就可分析烟道气中一氧化碳、二氧化碳和氧气等组分，该法具有分析速度快、重复性好、准确度高的特点，有较大的实用价值。     

渣油在加氢处理中的性质和结构变化规律研究

利用渣油加氢处理中试装置,获得了经过脱金属催化剂、脱硫催化剂和脱氮催化剂的系列渣油加氢处理产物,分析了各产物的性质。随加氢深度增加,硫、氮、残炭、镍和钒在渣油加氢产物中的的质量分数降低,总脱除率分别为84.9%、51.3%、62.8%、84.8%和94.0%。各产物的组分分布发生变化,饱和分组分增加,芳香分、胶质、沥青质组分减少,重组分胶质和沥青质组分的转化分别达到了57.5%和73.3%。以核磁共振为基础计算了渣油加氢产物组分的平均结构参数。结果表明,芳香分和胶质组分单元结构芳香环数和环烷环数减少,芳香碳分率fA、环烷碳分率fN和烷基碳分率fP变化不明显;而沥青质分子fA增加,fN和fP降低。从平均结构参数还可以看出,不同加氢产物同一种组分在结构上有其共性,但不同组分有明显区别。     

水中氟化物国际标准检验方法的验证及其比较

介绍水中氟化物国际标准检验方法的验证结果,其中包括了干扰实验、标准曲线、准确度、精密度、检出限等.并将本方法测定结果与国标同类方法进行了比较.结果表明,该方法抗干扰性好,测量精度高,其标准曲线范围宽,点数设计合理,优于国标中的同类方法.应加以采纳和推广.     

The Direct catalytic asymmetric cross-Mannich reaction: a highly enantioselective route to 3-amino alcohols and alpha-amino acid derivatives

The first proline-catalyzed direct catalytic asymmetric one-pot, three-component cross-Mannich reaction has been developed. The highly chemoselective reactions between two different unmodified aldehydes and one aromatic amine are new routes to 3-amino aldehydes with dr>19:1 and up to >99 % ee. The asymmetric cross-Mannich reactions are highly syn-selective and in several cases the two new carbon centers are formed with absolute stereocontrol. The reaction does not display nonlinear effects and therefore only one proline molecule is involved in the transition state. The reaction was also catalyzed with good selectivity by other proline derivatives. The Mannich products were converted into 3-amino alcohols and 2-aminobutane-1,4-diols with up to >99 % ee. The first one-pot, three-component, direct catalytic asymmetric cross-Mannich reactions between unmodified aldehydes, p-anisidine, and ethyl glyoxylate have been developed. The novel cross-Mannich reaction furnishes either enantiomer of unnatural alpha-amino acid derivatives in high yield and up to >99 % ee. The one-pot, three-component, direct catalytic asymmetric reactions were readily scaled up, operationally simple, and conductible in environmentally benign and wet solvents. The mechanism and stereochemistry of the proline-catalyzed, one-pot, three-component, asymmetric cross-Mannich reaction are also discussed.     

Study on the Cracking Mechanism of 1,1,2-Trichloro-1,2,2-trimethyldisilane Catalyzed by Aluminum Chloride

The cracking mechanism of 1,1,2-trichloro-l,2,2-trimethyldisilane catalyzed by aluminum chloride is investigated by DFT and MP2 methods. The reactants decompose in two ways, which are competing response. The reaction pathways are both by three steps. And the two reaction channels were both exothermic reaction. The heat of the overall reaction was –293.372 kJ·mol-1. The rate determining steps are the third and first steps, respectively. The Standard Gibbs Free Energy Change is the same, –297.55 kJ·mol-1. The Standard Equilibrium Constant is 1.354 × 1052. The theoretical productivity is high under normal temperature and pressure. The theoretical results agreed well with the experimental data.     

Effect of Bee Pollen on the Mechanical and Thermal Properties of Starch Films

The use of casein, starch and bee pollen as biodegradable materials has been promise. The objective of this work was the development and characterization of films containing casein, pollen and starch. The films were obtained by casting process and the solvent evaporation was performed at 40 °C/24 h. The films characterization was carried out by microscopy, thermal analysis, opacity test, mechanical properties and barrier methods. The starch films presented heterogeneous on microscopy analysis. The thermal behaviors of pollen films were similar. The formulation containing only pollen 3% was unable to form film. The introduction of pollen in starch film formulation improved the mechanical characteristic and thermal stability of films.     

质子型离子液体N,N-二甲基乙醇胺丙酸盐的密度、粘度及电导率

在283.15-333.15 K温度范围内, 测量了质子型离子液体N,N-二甲基乙醇胺丙酸盐(DMEOAP)的密度、粘度及电导率. 讨论了温度对密度、粘度和电导率等物理化学参数的影响. 通过经验和半经验方程得到了该离子液体的热膨胀系数、分子体积、标准摩尔熵及晶格能等热力学性质参数. 由电导率和密度计算出了该离子液体的摩尔电导率. 利用Vogel-Fulcher-Tamman (VFT)方程, 将测量的动力粘度和电导率对温度拟合, 得到了动力粘度和电导率随温度变化方程式.并通过Walden规则, 建立了粘度与摩尔电导率之间的联系.     

Functional Properties and Molecular Degradation of Schizostachyum Brachycladum Bamboo Cellulose Nanofibre in PLA-Chitosan Bionanocomposites

The degradation and mechanical properties of potential polymeric materials used for green manufacturing are significant determinants. In this study, cellulose nanofibre was prepared from Schizostachyum brachycladum bamboo and used as reinforcement in the PLA/chitosan matrix using melt extrusion and compression moulding method. The cellulose nanofibre(CNF) was isolated using supercritical carbon dioxide and high-pressure homogenisation. The isolated CNF was characterised with transmission electron microscopy (TEM), FT-IR, zeta potential and particle size analysis. The mechanical, physical, and degradation properties of the resulting biocomposite were studied with moisture content, density, thickness swelling, tensile, flexural, scanning electron microscopy, thermogravimetry, and biodegradability analysis. The TEM, FT-IR, and particle size results showed successful isolation of cellulose nanofibre using this method. The result showed that the physical, mechanical, and degradation properties of PLA/chitosan/CNF biocomposite were significantly enhanced with cellulose nanofibre. The density, thickness swelling, and moisture content increased with the addition of CNF. Also, tensile strength and modulus; flexural strength and modulus increased; while the elongation reduced. The carbon residue from the thermal degradation and the glass transition temperature of the PLA/chitosan/CNF biocomposite was observed to increase with the addition of CNF. The result showed that the biocomposite has potential for green and sustainable industrial application.     

有机锡化合物为中性载体的高选择性硫氰酸根离子电极

使用硫氰化银与硫化银作膜活性物质的固态硫氰酸根离子选择电极,由于受卤素离子如Cl^-、Br^-和I^-干扰很大而限制了应用.以钴(Ⅲ)卟啉或维生素B₁₂衍生物为载体的电极对SCN^-有较高的选择性^[1,2],使SCN-选择电极得到了较大的发展.     

乳状液膜体系分离提取铜离子

以Span80-对氨基苯磺酸(APS)-NH3液膜体系分离提取Cu2+。最佳分离条件为:制乳搅拌速度3500r/min,制乳时间及乳水混合时间分别为10min和20min,乳水比和油内比分别为0.38和0.44,APS、Span80和液体石蜡浓度分别为11%、4.4%和2.2%,内相NH3和外相HCl浓度分别为4.0mol/L和0.5mol/L。用该体系分离提取了模拟样中的Cu2+。     

二氧化硅/聚苯乙烯复合微球的制备及作为固相萃取填料的研究

以分散聚合法制备了二氧化硅/聚苯乙烯单分散复合微球,以红外光谱、透射电镜(TEM)、扫描电镜(SEM)等手段对其进行了表征。以合成的二氧化硅/聚苯乙烯作为固相萃取填料制作固相萃取小柱。通过固相萃取与液相色谱联用,测定了水中邻硝基酚、间硝基酚、对硝基酚和辛基酚、壬基酚,考察了固相萃取条件对固相萃取柱性能的影响,选择了最佳的色谱分离条件。结果表明,自制固相萃取小柱对水中硝基酚、烷基酚的萃取率高,与HPLC联用测定结果重现性好,邻硝基酚、间硝基酚、对硝基酚、辛基酚、壬基酚的最低检出限分别为0.90、0.72、0.62、0.38和0.41μg/L。