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1.
Viktor G. Berezkin Irina V. Malyukova Victor R. Alishoev Jaap de Zeeuw 《Journal of separation science》1996,19(5):272-276
In capillary gas-solid chromatography where interactions between solute and carrier gas and adsorption of the solute on the surface of the adsorbent are considered to be imperfect, it has been shown that chromatographic retention is determined largely by adsorption processes. It has been established that correlation relationships k(P2)=A k(P1) + B, where k is the retention factor, and A and B are equation constants, was valid for use of different carrier gases P1 and P2. Column efficiency could be improved by use of carbon dioxide. The advantages of using carbon dioxide as the carrier gas were investigated. 相似文献
2.
The dependence of retention factork
i
, relative retention time α
i
, and retention indexI
i
of organic compounds on the average pressure (p
av) of the carrier gas (helium) was studied experimentally using a long narrow-bore capillary column with the SE-30 nonpolar
phase at 120°C. The linear dependencesk
i
=f(p
av), α
i
=φ(p
av), andI
i
=φ(p
av) obtained previously were found to be in good agreement with experimental data. Invariant relative retention valuesk
0,i
, α
0,i
, andI
0,i
, which do not depend on the helium pressure, were determined for some organic compounds of various chemical classes. The
dependence of the relative retention on the carrier gas pressure needs to be taken into account in precision measurements
and in experiments with narrow-bore capillary columns.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 314–316, February, 1998. 相似文献
3.
A second-order non-linear partial different equation was derived to describe the dependence of carrier gas pressure in the column on the column distance and the time under temperature programmed conditions. This equation was solved numerically by the modified finite difference method for various column parameters. Constant inlet and outlet pressures were used as boundary conditions. The retention times calculated on assumption of a constant pressure profile along the column. Significant differences between retention times of corresponding solutes calculated by the two methods were found, especially when relatively long columns(L>50m) with small internal diameter(d<0.3mm)and high temperature program rates (r>5°/min)are used. 相似文献
4.
The dependence of the width of the chromatographic zone on retention time for capillary columns was studied theoretically
and experimentally.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 320–322, February, 1997. 相似文献
5.
The dependence of capacity factors on the pressure of a carrier gas in capillary adsorption chromatography was studied theoretically and experimentally. The equation deduced theoretcally satisfactorily conformed to experimental data.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1981–1983, October, 1995.The authors are grateful to A. A. Lopatkin for useful discussion and critical comments and to the Chrompack company (Netherlands) for the column that was kindly supplied for the work. 相似文献
6.
7.
A new type of capillary column for gas chromatography was proposed. A sorbent layer (for example, stationary liquid phase) is supported on the internal capillary surface, and the internal (interstitial) volume is packed with nonporous large particles of a sorbent (particle diameter is 0.1—0.6 of the capillary internal diameter). The external surface of the particles can also be coated with the sorbent layer (for example, stationary liquid phase). The specific separation efficiency (number of separation) on the new type column is by 1.6—2.3 times higher than that of the initial classical capillary column. 相似文献
8.
Berezkin V. G. Korolev A. A. Malyukova I. V. Mardanov R. G. Khotimskii V. S. Yampol"skii Yu. P. 《Russian Chemical Bulletin》2001,50(7):1228-1232
The retention factor and height equivalent of a theoretical plate for gaseous hydrocarbons C1—C4 were studied on capillary columns with the layer of the new polymeric adsorbent polytrimethylsilylpropyne (PTMSP) as functions of the nature and pressure of the carrier gas. The retention factor k increases in the series helium < nitrogen < carbon dioxide. The k values depend linearly on the average pressure of the carrier gas in a capillary column with the adsorption PTMSP layer. 相似文献
9.
The introduction of selected fractions from a liquid chromatograph into a gas chromatograph has been described; however, analyses were performed by off-line experiments requiring collection and reinjection of the separate fractions or by on-line procedures where disadvantageously, only a fraction of the separated peak or a well resolved component in a mixture could be introduced into a gas chromatograph. This disadvantage is overcome by the apparatus and method described in this paper, which utilizes a multidimensional chromatography system employing a high efficiency, packed capillary LC column coupled on-line to a capillary gas chromatograph. The liquid chromatograph (so designed) can act as a highly efficient clean-up or chemical class fractionation step prior to introduction into the gas chromatograph, significantly reducing sample preparation times in many applications. Thus minor components in a complex matrix can be determined without prior sample clean-up, an example of which is the determination of polychlorinated biphenyls in a complex hydrocarbon matrix. 相似文献
10.
Summary Flexibility, strength and adsorption inertness of fused-silica capillaries permits their extensive application for the preparation
of micro-packed columns in gas chromatography. Decreasing the column diameter (from 0.5 to 0.15 mm) and the diameter of the
sorbent particles (from 100 to 5 μm) results in a marked reduction of the height equivalent to a theoretical plate (HETP),
as well as in diminishing the dependence of the HETP on the carrier gas flow rate.
The chromatographic characteristics of fused-silica capillary micro-packed columns and open-tubular columns are compared.
The fused-silica capillary micro-packed column can be used to advantage for performing rapid and trace analyses and have been
shown to be adapted for application in gas-solid chromatography. Separation of organic and inorganic compounds on fused-silica
capillary micro-packed columns is illustrated by practical examples.
Presented at the 15th International Symposium on Chromatography, Nürnberg, October 1984 相似文献
11.
Summary A new version of gas-solid chromatography (GSC) of hydrogen isotopes and spin isomers which makes use of the adsorbable dihydrogen
carrier gases (H2, HD and D2) is described. Major advantages of the new technique in comparison with conventional GSC with inert carrier gases are discussed.
The new version of GSC was found to be a powerful tool for acquisition of the data necessary to design adsorption systems
to separate hydrogen isotopes. 相似文献
12.
Gas-chromatographic analysis of complex mixtures is simplified enormously by the use of the simultaneous dual capillary technique. The advantages over a single-column system are that the components are more reliably identified and quantified. After integration has taken place, the data from both capillaries are cor-related with the aid of a computer program whose principles are described. 相似文献
13.
Summary Methylbenzenes, pyridines and pyrazines were investigated on fused-silica and glass capillary columns coated with SE-30 and
PEG-40M/KF liquid phases, at two temperatures, 80° and 110°C. The contribution of the methylene groups to the partial molar
free sorption energy was determined for methylpyridines and pyrazines. Equations are proposed for the calculation of the retention
indices of methyl pyridines and pyrazines. These equations are based on the ortho- and α-effects of the methyl groups. The
predicted indices have been experimentally tested for six dimethyl- and trimethylpyridines, and four methylpyrazines. Good
accuracy of the calculation permits to use this method for the identification of methylpyridines and pyrazines in complex
mixtures.
Enlarged text of the paper presented at the Eighth International Symposium on Capillary Chromatography, Riva del Garda, Italy,
May 19–21, 1987. 相似文献
14.
Capillary columns offer the toxicologist several advantages over packed columns. We have presented a highly reproducible screening procedure based on the retention index system and have shown the use of capillary columns for routine quantitation. We are currently expanding the use of these columns in our laboratory and predict that they will be in routine use by most toxicologists in the near future. 相似文献
15.
Eva Matisov 《Journal of separation science》1992,15(4):213-218
The scope of the principal techniques employed for the analysis of hydrocarbon mixtures is discussed, with emphasis on the analysis of one and two ring aromatic compounds by single column capillary gas chromatography. The paper considers both the column and the selection of the temperature regime (isothermal and temperature programmed). Much space is devoted to the characterization of the compounds by means of retention data. 相似文献
16.
17.
The influence of humid carrier gases (nitrogen and carbon dioxide) on the retention of polar compounds in a capillary column
with polypropylcyanophenylsiloxane stationary liquid phase OV-225 was studied. It is noted that when humid carbon dioxide
is used as the carrier gas, the retention of primary amines sharply increases.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1129–1131, June, 1999. 相似文献
18.
Dependences of sorption energies of sulfur-, oxygen-, and nitrogen-containing heterocyclic compounds on the nature of heteroatoms, structure of substituents and their position in the ring were studied. The contributions of heteroatoms, functional and alkyl groups to the energy of dispersive interaction of position isomers with nonpolar stationary phases were determined for imidazoles, piperidines, morpholines, thiomorpholines, dioxalanes, oxathiolanes, dithiolanes, thiophenes, and furans. The nonequivalence of contributions of the same substituents to the sorption energy of each of the heterocyclic compounds, depending on the nature of the heteroatom and position of the substituent, was shown. The obtained values of contributions of heteroatoms and substituents can be used for apriori calculation of retention indices of position isomers of five- and six-membered heterocycles containing one or two heteroatoms in the ring.Translated from lzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 2033–2038, August, 1996. 相似文献
19.
采用毛细管气相色谱法(GC)测定了二乙基二硫的含量.结果表明,二乙基二硫含量在0.010.4g/L范围内具有良好的线性关系,平均回收率为99.91%;该方法简便、准确、重复性好,可方便地用于二乙基二硫含量的测定. 相似文献
20.
V. G. Berezkin A. A. Korolev I. V. Malyukova R. G. Mardanov 《Russian Chemical Bulletin》1997,46(12):2064-2073
The effects of the carrier gas nature and pressure on the relative retention values of organic compounds were studied using
a series of capillary columns differing in the film thickness of the polar stationary phase (PEG-20M). Relative retention
depends linearly on the carrier gas pressure. This dependence becomes more pronounced in the following order of carrier gases:
helium < nitrogen < carbon dioxide. The limiting relative retention at a carrier gas pressure approaching zero rather than
relative retention values measured experimentally (relative retention time, Kovats retention index,etc.) is an invariant characteristic of a compound subjected to chromatography. For the carrier gases studied, the limiting retention
values almost does not depend on the nature of the carrier gas used. The limiting indicating the complex absorption-adsorption
nature of these parameters. Dissolution of a carrier gas in the stationary liquid phase has an effect on the relative retention.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2177–2186, December, 1997. 相似文献