共查询到20条相似文献,搜索用时 15 毫秒
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叙述了高温凝胶(渗透)色谱(GPC)的流动相中出现气泡时的现象,指出气泡的出现对仪器运行和样品测试的影响,以及排除气泡的方法和过程.对可能出现气泡的原因进行了分析,讨论了避免出现气泡现象需要注意的问题和采取的措施. 相似文献
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《液相色谱法及相关技术杂志》2012,35(5):875-923
Abstract This Chapter is devoted to a particular mode of liquid chromatography: Gel Permeation Chromatography (G.P.C.). The field of G.P.C. mainly concerns polymers but can also be applied to small organic molecules where, as well see later, the technique is more closely related to classical liquid chromatography. 相似文献
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《液相色谱法及相关技术杂志》2012,35(8):1297-1309
Abstract The mechanisms are discussed which control the GPC elution of ionic solutes, both the polyelectrolytes and the low molecular salts. The processes involved are quite general and valid in organic and in aqueous solvents. The conclusion is that gel permeation chromatography is a powerfull method to characterize poly-electrolytes; and it is shown that the correct data on molecular weight distribution can be obtained when the ionic content in the eluent is larger than 5.10?2 M and when the concentration injected is lower than the critical overlapping concentration. The interpretation of chromatograms can be performed using the universal calibration and a viscosimetric detector. 相似文献
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《液相色谱法及相关技术杂志》2012,35(9):1399-1416
Abstract Aquas gel permeation chromatography of insulin under denaturating conditions has been successfully performed on three different chromatographic supports. The separation pattern was identical to that obtained on soft gels (Sephadex, BioGel). The elution time was 10-20 min, recovery 98-100%. 相似文献
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《液相色谱法及相关技术杂志》2012,35(3):401-424
Abstract This paper describes the error involved in the utilization of nonmonodisperse polymer standards for the calibration of GPC columns. It also demonstrates that the computer technique developed by McCrackin (1) produces a calibration equation from poly-disperse standards that avoids this error. This equation, referred to as dispersion-compensated, can successfully be incorporated into the theory of universal calibration to remove the necessity of assuming infinite instrumental resolution. Furthermore, it is shown that only the calibration equation compensated for number-average molecular weights is a true universal form. 相似文献
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通过一系列实验,发现在凝胶色谱中柱温对柱效的影响随相对分子质量的增大而增大;溶质的淋洗体积与柱温有关,而选择性因子与柱温无关;升高柱温只改善大分子间的分离度,对小分子间的分离度影响较小;只要保持整个体系恒温以及在相应温度下制定一条可靠的校正曲线,则柱温对测定结果无影响。 相似文献
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《液相色谱法及相关技术杂志》2012,35(6):1367-1380
Abstract The elution behaviour of alcohols in the systems Bio Beads SX-8/dichloromethane and Sephadex LH-20/dichloromethane is investigated. On Bio Beads SX-8 the elution volumes are lower than expected for normal GPC behaviour, which is perhaps due to hydrogen bonding in solution. On Sephadex LH-20 adsorption takes place by means of hydrogen bonding, which can be used for very selective separations. 相似文献
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《液相色谱法及相关技术杂志》2012,35(10):1481-1496
Abstract A high-performance gel permeation chromatographic (GPC) method was developed to determine the molecular weight distribution of pectins. The chromatographic system consisted of a hydrophilic coated silica (SynChropak) as the packing and a pH 3.7 acetate buffer as the mobile phase. By use of this system, high-methoxy, low-methoxy, and amidated pectins could be analyzed within fifteen minutes. By determining partition coefficients (Kd) of pectins as a function of mobile phase composition, Kd values were found to be independent of ionic strength from 0.055 to 0.7 M using pH 3.7 acetate buffers, which was in agreement, with intrinsic viscosity data. 相似文献
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《液相色谱法及相关技术杂志》2012,35(10):1825-1845
Abstract This paper describes the development of the gel permeation chromatography (GPC) technique for the measurements of cyclic trimer content, molecular weights, and molecular weight distribution of polyethylene terephthalate (PET), utilizing a solvent system of o-chlorophenol-chloroform. Mark-Houwink constants for this solvent system are also described. The GPC technique was applied to the study of the cyclic trimer content, molecular weights and molecular weight distribution of a variety of commercial PET resins. The results indicate that the cyclic trimer content in PET is dependent on molecular weight, polycondensation process and catalyst system. Solidstate polymerized PET contains less cyclic trimer than PET made by the melt-phase process of the same molecular weight. The cyclic trimer content in solid-stated PET appears to be dependent on the conditions of solid-state polymerization. The polydispersity index determine for a variety of PET samples is higher than the theoretically predicted value of 2.0; however, there is no systematic dependence on molecular weight or polycondensation process. 相似文献
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《液相色谱法及相关技术杂志》2012,35(5):693-726
Abstract The recent literature on aqueous gel permeation chromatography is reviewed. The chromatography of charged and uncharged solutes has been considered. A major emphasis has been to document the newer types of column packings for use in aqueous systems and their typical applications. 相似文献
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《液相色谱法及相关技术杂志》2012,35(3):309-318
Abstract Polymers from wood, including cellulose via the methylol derivative, are soluble in dimethyl sulfoxide (DMSO). To perform gel permeation chromatography of these high polymers, a packing material was sought which combined adequate pore size with stability in DMSO. Contrary to recommended practice, it was discovered that gel permeation chromatography in DMSO can be performed on prepacked, high-performance columns of μ-Styragel without adverse effects from bead swelling. When using the methylol derivative of cellulose, it is necessary to freeze dry the reaction mixture to obtain a product which gives reproducible results from gel permeation chromatography. 相似文献
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《液相色谱法及相关技术杂志》2012,35(8):1385-1394
Abstract Saturated hydrocarbons are generally eluted according to molecular volumes in gel permeation chromatography (GPC). Other compounds, containing polar groups such as hydroxyl and carbonyl groups, deviate from the molecular volume/elution count relationship which is prepared using saturated hydrocarbons. The deviation is more or less observed regardless of the kinds of eluents. In this paper, this problem is investigated in detail with respect to infrared(IR) and proton magnetic resonance(NMR) spectra, and concentration dependences of peak heights and elution volumes in GPC. IR and NMR spectra reveal that alcohols, ketones and esters are strongly solvated by eluent molecules such as chloroform and tetrahydrofuran(THF). The solvation effect leads to faster elution for these compounds than expected for aliphatic hydrocarbons. On the other hand, the concentration dependences of elution counts and peak heights prove the adsorption of amines on polystyrene gel in chloroform. In fact, the elution rates of amines and polychlorides are retarded. In the case of aliphatic carboxylic acids, the elution mechanism is more complicated: association and adsorption effects would be overlapped. 相似文献
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《液相色谱法及相关技术杂志》2012,35(14):3073-3083
Abstract In gel permeation chromatography (GPC), several compounds deviate from the molecular volume/elution count relationship which is prepared using satured hydrocarbons. In this paper, this problem is investigated in detail using thiouracil in aqueous solution as a model chromatographic adsorbate. The concentration dependences of elution counts and peak heights prove the adsorption of thiouracil on Sephadex G-25 when water is the solvent. Thus to investigate further the mechanisms of adsorption responsable for the chromatographic behaviour, thiouracil-Sephadex interac—tions were investigated by studying equilibrium adsorption. Isotherms of type IV of BDDT classification were found which are typically associated with a weak adsorption such as physisorption, on a porous solid. The effect of water structure perturbants, ionic strength and pH on this adsorption was consistent with the-hypothesis that with water as a solvent both aromatic adsorption and electrostatic interaction are the determinants of the affinity of this gel for a thiouracil compound. This may be particularly useful since results of equilibrium adsorption isotherms are frequently used to develop liquid chromatographic theories. 相似文献
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《液相色谱法及相关技术杂志》2012,35(2):287-299
Abstract In this study, the ways in which GPC can be integrated into the crime laboratory's present analytical scheme for polymer products will be examined. Fingerprint chromatograms and chromatograms illustrating molecular weight determination of two types of commonly encountered physical evidence (fibers and tail light lense fragments) will be compared and discussed. The techniques involved in sample preparation and data interpretation will be given. Finally the potential advantages of GPC for use in the crime laboratory will be presented. 相似文献
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研究了均聚和共聚甲醛在六氟异内醇中的凝胶渗透色谱(GPC)。对共聚甲醛出现的缔合现象从主链结构作了解释,并找到了避免缔合的方法;对共聚甲醛GPC淋洗曲线上的异常小峰从聚合机理角度进行了探讨,推测得到小峰所对应的物质。确定了以六氟异丙醇为溶剂的聚甲醛的凝胶色谱表征方法,并探索采用凝胶色谱-粘度计联用法得到分子量和分子量分布结果。 相似文献
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凝胶渗透色谱用大孔硅胶的制备 总被引:1,自引:0,他引:1
采用NaCl、LiCl~KNO33组分盐,通过一次焙烧扩孔,制备了孔径4×102~1×103nm的大孔硅胶,其孔容可达0.8mL/g,孔度为0.65以上。实验结果表明,可用于GPC分离相对分子质量为1.5×107以下的聚丙烯酰胺。 相似文献