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1.
张桂琴  谢红卫 《分析化学》1994,22(5):485-487
本文工作研究了极性、强极性固定液直接涂渍在硅膜改性弹性玻璃毛细管内壁上,经优化温度老化色谱柱,成功地研制出OV-225,DEGS,Silar5,Silar9,Silar10等硅膜改性弹性玻璃毛细管柱,各种柱子均具有柱效高,热稳定性好的色谱性能。  相似文献   

2.
用壁处理办法对高性能毛细管电泳的毛细管柱进行改性,在Bio-Rad HPE-100中用肽测得组分的平均柱效为200000/m,使用寿命在200次以上。对纤维素酶.尿酶等一系列的样品作了分离和测定,尿酶5次重复测定的相对标准偏差小于1%。在10min内分离并测定了由细胞瘤培养的实际样品中的抗乙肝抗体(HBsAG),反映迁移时间重复性的相对标准偏差为1.87%,并作出了相应校正曲线。  相似文献   

3.
一种新型手性毛细管柱的研制及其性能   总被引:3,自引:0,他引:3  
报道了用硅酮固定液OV-17改性,以自制的非水溶性β-环糊精聚合物为固定相,采用超动态法制备出柱效高,热稳定性好的弹性石英毛细管柱。对毛细管柱的活性、极性、热稳定性等色谱性能进行了考察,已对一系列手性化合物进行拆分。  相似文献   

4.
磷酸和水蒸气联合改性的HZSM-5的物化表征及催化研究   总被引:2,自引:0,他引:2  
研究了磷和水蒸气联合改性HZSM-5样品的物化和催化性能。XRD和IR研究表明,没有新的晶相出现。NH3-TPD研究样品的酸性表明,经过磷改性后的样品的酸量明显下降。经过水热处理的样品的BET比表面明显降低,这可能归因于磷物种和铝物种对孔道的堵塞。氮吸附-脱附等温线研究表明,等温线为I型和IV型的复合型,滞后环为H4型。联合改性样品的正庚烷裂化转化率高于仅仅由水蒸气改性样品的正庚烷裂化转化率,从而显示出磷物种对沸石分子筛高温水蒸气脱铝的抑制作用。  相似文献   

5.
镧和铈改性对氧化铝性质的影响   总被引:4,自引:0,他引:4  
卢伟光  龙军  田辉平 《催化学报》2003,24(8):574-578
 以拟薄水铝石为前驱物,采用溶胶法制备了γ-Al2O3,在制备 初期添加硝酸镧或硝酸铈对氧化铝进行改性,并使用红外光谱、氮物理 吸附和X射线衍射等方法对样品进行了表征.实验表明,稀土添加物覆 盖了部分氧化铝的表面羟基.在1000℃下对样品烧结行为的考察发现, 添加镧或铈化合物都能提高γ-Al2O3的抗烧结性能和高温稳定性,镧 改性样品的效果略优于铈改性样品.烧结动力学研究发现,制备的氧化 铝的烧结机理为体相扩散,加入稀土有效地阻止了氧化铝颗粒内的体相 扩散.用微反装置测定了改性样品的反应性能,发现铈改性样品有一定 的裂化性能和脱氢性能,而镧改性样品几乎无催化活性.  相似文献   

6.
寇登民  云希勤 《分析化学》1994,22(2):186-189
本文在中等极性和强极性玻璃毛细管柱研究的基础上(1),对弱极性和非极性固定液在硫酸钡微晶改性表面上的涂渍情况作了详细的研究。研究表明,只要对这种改性表面进行钝化处理,即可途渍出高效弱极性和非线性毛细管柱。  相似文献   

7.
采用XRD表征了水蒸气和磷联合改性的HZSM-5沸石分子筛的结构.通过NH3-TPD和N2吸附脱附研究了样品的酸性和比表面.采用正庚烷的裂化反应研究了样品的裂化活性,研究结果表明,磷改性样品与母体样品相比,经过水蒸气处理后显示出较高的酸量和正庚烷裂化活性.上述结果首次用模型簇和计算量子化学方法进行了解释.采用Gaussian94软件包和PM3半经验量子化学方法对模型簇进行了全优化和频率分析.计算结果显示磷改性后样品的脱铝补硅反应热大于母体样品脱铝补硅反应热,从而显示出磷对骨架的稳定化作用.  相似文献   

8.
利用固定吸附床研究了不同金属离子改性的Y分子筛时一氧化氮的吸附性能.在所用的样品中,钴离子改性的Y分子筛显示出了最良好的吸附性能.钴离子改性的Y分子筛对一氧化氮吸附的穿透时间随着钴含量、浸渍液的pH值和粘合剂三氧化铝用量的变化而变化.另外.穿透时间还随吸附温度的升高而缩短.  相似文献   

9.
采用离子交换法制备了La改性的β分子筛催化剂,通过X射线衍射(XRD)、扫描电镜(SEM)和氨气程序升温脱附(NH3-TPD)手段表征了改性分子筛样品,并研究了其在C9芳烃与丙烯烷基化反应中的催化性能。实验结果表明,用La(NO3)3改性后,β分子筛的骨架结构和形貌未发生明显变化,但酸量降低,弱酸与强酸的比例增大;用8%La(NO3)3改性的样品较原分子筛有更好的烷基化催化活性,用浓度大于8%的La(NO3)3改性后β分子筛的烷基化活性受到抑制,异构化、脱烷基反应趋势增强。  相似文献   

10.
改性Y沸石的孔结构与催化性能   总被引:2,自引:0,他引:2  
测定了不同方法改性的Y沸石样品的N_2吸附和脱附等温线, 并计算了样品的微孔、大孔和二次孔的孔容和表面积, 以及样品的二次孔分布, 证实改性方法对样品的孔结构有显著的影响。同时, 还考察了不同尺码探针分子在改性Y沸石样品上的酸催化反应活性, 将所得数据与样品的酸量、酸强度和二次孔容相关联, 取得了满意的结果。说明对大尺码反应分子, 改性过程中生成的大孔径二次孔, 对提高沸石催化剂的反应活性是有利的。  相似文献   

11.
毛细管电泳涂层柱技术的进展   总被引:8,自引:0,他引:8  
康经武  陆豪杰  欧庆瑜 《色谱》1998,16(1):26-29
毛细管电泳涂层柱是解决蛋白质在毛细管壁吸附的最有效的方法。较为系统地综述了毛细管电泳涂层柱的几种制作方法,指出了毛细管电泳涂层柱(包括毛细管电色谱柱)的发展趋势,39篇。  相似文献   

12.
The use of etched, chemically modified, capillaries with a rectangular inner channel for open tubular electrochromatography is investigated. Comparisons of separation capabilities are made between circular and rectangular capillaries undergoing the same etching and chemical modification processes. With the long dimension of the rectangular column aligned in the direction of the optical light path, the relative sensitivities of the two capillary geometries are evaluated. The electrochromatographic properties of two catechins found in tea are investigated on the rectangular etched octadecyl-modified capillary.  相似文献   

13.
Surface modification of the inner capillary wall in CE of proteins is frequently required to alter EOF and to prevent protein adsorption. Manual protocols for such coating techniques are cumbersome. In this paper, an automated covalent linear polyacrylamide coating and regeneration process is described to support long‐term stability of fused‐silica capillaries for protein analysis. The stability of the resulting capillary coatings was evaluated by a large number of separations using a three‐protein test mixture in pH 6 and 3 buffer systems. The results were compared to that obtained with the use of bare fused‐silica capillaries. If necessary, the fully automated capillary coating process was easily applied to regenerate the capillary to extend its useful life‐time.  相似文献   

14.
The fabrication, properties, and applications of etched chemically modified capillaries for electrophoretic analysis are reviewed. It is shown that the etching process creates a surface that is fundamentally different than a bare fused silica capillary. The new surface matrix produces unique electroosmotic flow properties and is more compatible with basic and biological compounds. After chemical modification of the surface, the bonded organic moiety (stationary phase) contributes to the control of migration of solutes in the capillary. Both electrophoretic and chromatographic processes take place in the etched chemically modified capillaries leading to a variety of experimental variables (pH, buffer type, presence and amount of organic modifier, and temperature) that can be used to optimize separations. A number of examples of separations on these capillaries are presented as well as data on column ruggedness and reproducibility.  相似文献   

15.
The development of efficient and sensitive analytical methods for the separation, identification and quantification of complex biological samples is continuously a topic of high interest in biological science. In the present study, the possibility of using a polyether ether ketone (PEEK) capillary for the CE separation of peptides, proteins and other biological samples was examined. The performance of the tubing was compared with that of traditional silica capillaries. The CE analysis was performed using contactless conductivity detection (C4D), which eliminated any need for the detection window and was suitable for the detection of optically inactive compounds. In the PEEK capillary the cathodic EOF was low and of excellent stability even at extremes pH. In view of this fast biological anions were analyzed using an opposite end injection technique without compromising separation. A comparison of the performances of fused‐silica and polymer capillaries during the separation of model sample mixtures demonstrated the efficiency and separation resolution of the latter to be higher and the reproducibility of the migration times and peak areas is better. Furthermore, PEEK capillaries allowed using simple experimental conditions without any complicated modification of the capillary surface or use of an intricate buffer composition. The PEEK capillaries are considered as an attractive alternative to the traditional fused‐silica capillaries and may be used for the analysis of complex biological mixtures as well as for developing portable devices.  相似文献   

16.
The sol-gel surface modification is used for capillary isoelectric focusing of microorganisms and biopolymers. The coating strongly decreases the electroosmotic flow so that it enables the use of the short capillaries down to 100 mm in the separation length. The examples of capillary isoelectric focusing of the low-molecular-mass pI markers and mixed cultures of microbial populations of Escherichia coli, Candida albicans, Staphylococcus epidermidis, and Enteroccocus faecalis with UV detection are shown. It is possible to quantify bacterial cells according to their peak areas; the minimum detectable number of microbial cells was 5 x 10(2)-1 x 10(3). The compatibility of sol-gel capillaries with sensitive fluorometric detection of fluorescent pI markers together with fluorescein labeled proteins is demonstrated.  相似文献   

17.
Avidin was immobilized covalently onto the inner surface of fused silica capillaries as a stationary phase in an open tubular capillary electrochromatography (OT-CEC) for chiral separations. The modification was attained by a combination of glutaraldehyde with both an amino-silylated fused silica surface and avidin using a Schiff base formation reaction. This method couples the advantage of high efficiency and small consumption of a chiral selector with the possibility of UV detection without limitations of protein absorption. In addition, the prepared capillary was stable for 50 days with over 100 runs. To evaluate the electrochromatographic performance of the prepared capillaries, the chiral separation of abscisic acid and arylpropionic acids were investigated. Effects of the modification condition of protein, pH of running buffer, and an organic modifier on the enantioseparation were also investigated. In addition, the avidin immobilized capillary was employed for the selective chiral analysis with an electrospray ionization mass spectrometry (ESI-MS) detection scheme.  相似文献   

18.
Hamer M  Yone A  Rezzano I 《Electrophoresis》2012,33(2):334-339
We report a new method of immobilization of gold nanoparticles (AuNPs) on a fused-silica capillary through covalent binding. The resulting modified capillary was applied to electrophoretic systems to improve the efficiency of separation and the selectivity of selected solutes. The immobilization of AuNPs on the capillary wall was performed in a very simple and fast way without requiring heating. The surface features of an AuNP-coated capillary column were determined using the scanning electron microscopy. The chromatographic properties of AuNP-coated capillaries were investigated through variation of the buffer pH and separation voltage. Effective separations of synthetic peptides mixture were obtained on the AuNP-coated capillaries. The method shows a remarkable stability since it was reused about 900 times. The capacity factor was duplicated. Therefore, this modification is stable and can be applied to different separation purposes. A complex mixture of tryptic peptide fragments of HSA was analyzed in both the bare- and the AuNP-coated capillaries. Better electrophoretic peptide profile was observed when using the AuNP-coated capillary.  相似文献   

19.
Fused silica capillaries with an I.D. of 20 microns are etched and then chemically modified by the silanization/hydrosilation method to attach an octadecyl moiety for use in electrokinetic chromatography. The etched capillaries after chemical modification are shown to have an anodic electroosmotic flow below pH 4.5. In comparison to bare 20 microns capillaries and unetched but chemically modified 20 microns capillaries, the etched C18 fused silica tubes show better separation of mixtures of lysozymes and cytochrome c's under identical conditions of buffer, pH and applied voltage. It was also demonstrated that this open tubular approach to capillary electrochromatography was amenable to a number of different types of basic compounds ranging in size from typical small amines to biomolecules. As expected, pH is an important variable that must be controlled in order to obtain an optimized separation. Reproducibility studies verify the stability of the silicon-carbon linkage produced in this modification method so that column lifetimes of at least 300 injections can be expected.  相似文献   

20.
In this work, capillary electrophoresis was applied to protein profiling of fractionated extracts of maize. A comparative study on the application of uncoated fused‐silica capillaries and capillaries modified with hydroxypropylmethylcellulose, ω‐iodoalkylammonium salt and a commercially available neutral capillary covalently coated with polyacrylamide is presented. The coating stability, background electrolyte composition, and separation efficiency were investigated. It was found that for zeins separation, the most stable and efficient was the capillary coated with polyacrylamide. Finally, the usefulness of these methods was studied for the differentiation of zein fraction in transgenic and nontransgenic maize. Zeins extracted from maize standards containing 0 and 5% m/m genetic modification were successfully separated, but slight differences were observed in terms of the zein content. Albumin and globulin fractions were analyzed with the use of unmodified fused‐silica capillary with borate buffer pH 9 and the capillary coated with polyacrylamide with phosphate buffer pH 3. In the albumin fraction, additional peaks were found in genetically modified samples.  相似文献   

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