Studies of Polymer Properties via Inverse Gas Chromatography

1996 ◽  
Vol 69 (3) ◽  
pp. 347-376 ◽  
Author(s):  
Bincai(Pun Choi) Li
Keyword(s):  
Gas Chromatography ◽  
Stationary Phase ◽  
Mobile Phase ◽  
Inverse Gas Chromatography ◽  
Amorphous Polymer ◽  
Retention Volume ◽  
Polymer Surface ◽  
Gas Liquid Chromatography ◽  
Solvent Vapor ◽  
Carrier Gas

Abstract Gas Chromatosraphy (GC) using a polymer as the stationary phase to reveal the properties of the polymer — known as Inverse Gas Chromatography (IGC) — is in contrast to conventional GC where gaseous components in the mobile phase are separated and studied. Figure l(a) and l(b) are schematic diagrams showing the arrangement of apparatus in a gas Chromatograph for IGC. The column is filled with packings consisting of thin layer of polymer coated onto an inert support, typically Chromosorb W, Chromosorb G (70 ∼ 80 mesh, acid washed and dimethyldichlorosilane treated), or Teflon. The carrier gas, such as N2, H2, or He, acts as the mobile phase. The solvent, injected as a sharp pulse and vaporized immediately into the carrier gas stream at the entrance of the column, is called the probe. As the probe is carried forward, it is partitioned between the mobile gas phase and the stationary polymer phase. The time required to elute the probe through the column is called the retention time (elution is monitored in the detector and reflected on the recorder or integrator as a peak maximum). The corresponding amount of carrier gas needed is called the retention volume. The detector for the probe may be a thermal conductivity cell (TCD) or flame ionization detector (FID). When an FID is used, the flow of gas is diverted to the flow meter before it reaches the detector as shown in Figure l(b). Some notes on the experimental techniques will be discussed in Section IX. GC has been classified into Gas-Liquid Chromatography (GLC) and Gas-Solid Chromatography (GSC) according to whether the stationary phase is a liquid or a solid, respectively. In IGC, the process is GLC when the temperature of the polymer under investigation is far above its glass transition temperature Tg. The retention is due to absorption of the solvent vapor into the polymer bulk (an amorphous polymer above Tg is viewed as a liquid). When the temperature of the polymer is well below its Tg, the process is GSC and the retention mechanism becomes adsorption of the vapor onto the polymer surface. We shall initially discuss the GLC of polymers and then extend our discussions to GSC. Important applications of IGC to polymer research have been the studies of the thermodynamics of polymer-solvent and polymer-polymer interactions via GLC.

A Review: Uses of Gas Chromatography-Mass Spectrometry (GC-MS) Technique for Analysis of Bioactive Natural Compounds of Some Plants

2017 ◽  
Vol 9 (01) ◽  
Author(s):  
Abeer Fauzi Al-Rubaye ◽  
Imad Hadi Hameed ◽  
Mohanad Jawad Kadhim
Keyword(s):  
Gas Chromatography ◽  
Secondary Metabolites ◽  
Stationary Phase ◽  
Mobile Phase ◽  
Biological Activities ◽  
Anabolic Steroids ◽  
Gas Chromatography Mass Spectrometry ◽  
Gas Liquid Chromatography ◽  
Analytical Technique ◽  
Flame Ionization

Chromatography is the term used to describe a separation technique in which a mobile phase carrying a mixture is caused to move in contact with a selectively absorbent stationary phase. It also plays a fundamental role as an analytical technique for quality control and standardization of phyto therapeuticals. Gas Chromatography is used in the separation and analysis of multi component mixtures such as essential oils, hydrocarbons and solvents. Various temperature programs can be used to make the readings more meaningful; for example to differentiate between substances that behave similarly during the GC process. Intrinsically, with the use of the flame ionization detector and the electron capture detector (which have very high sensitivities) gas chromatography can quantitatively determine materials present at very low concentrations. Plants are a rich source of secondary metabolites with interesting biological activities. In general, these secondary metabolites are an important source with a variety of structural arrangements and properties. Gas chromatography - specifically gas-liquid chromatography - involves a sample being vapourised and injected onto the head of the chromatographic column. The sample is transported through the column by the flow of inert, gaseous mobile phase. The column itself contains a liquid stationary phase which is adsorbed onto the surface of an inert solid. The principle of gas chromatography is adsorption and partition. Within the family of chromatography- based methods gas chromatography (GC) is one of the most widely used techniques. GC-MS has become a highly recommended tool for monitoring and tracking organic pollutants in the environment. GC-MS is exclusively used for the analysis of esters, fatty acids, alcohols, aldehydes, terpenes etc. It is the key tool used in sports anti-doping laboratories to test athlete’s urine samples for prohibited performanceenhancing drugs like anabolic steroids. Several GC-MS have left earth for the astro chemistry studies. As a unique and powerful technology the GC-MS provides a rare opportunity to perform the analysis of new compounds for characterization and identification of synthesized or derivatized compound.

scholarly journals Practical Determination of the Solubility Parameters of 1-Alkyl-3-methylimidazolium Bromide ([CnC1im]Br, n = 5, 6, 7, 8) Ionic Liquids by Inverse Gas Chromatography and the Hansen Solubility Parameter

Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1346 ◽  
Author(s):  
Qiao-Na Zhu ◽  
Qiang Wang ◽  
Yan-Biao Hu ◽  
Xawkat Abliz
Keyword(s):  
Gas Chromatography ◽  
Ionic Liquids ◽  
Physicochemical Properties ◽  
Solubility Parameter ◽  
Room Temperature ◽  
Inverse Gas Chromatography ◽  
Retention Volume ◽  
Solubility Parameters ◽  
Hansen Solubility Parameter ◽  
Hansen Solubility

The physicochemical properties of four 1-alkyl-3-methylimidazolium bromide ([CnC1im]Br, n = 5, 6, 7, 8) ionic liquids (ILs) were investigated in this work by using inverse gas chromatography (IGC) from 303.15 K to 343.15 K. Twenty-eight organic solvents were used to obtain the physicochemical properties between each IL and solvent via the IGC method, including the specific retention volume and the Flory–Huggins interaction parameter. The Hildebrand solubility parameters of the four [CnC1im]Br ILs were determined by linear extrapolation to be δ 2 ( [ C 5 C 1 im ] Br ) = 25.78 (J·cm−3)0.5, δ 2 ( [ C 6 C 1 im ] Br ) = 25.38 (J·cm−3)0.5, δ 2 ( [ C 7 C 1 im ] Br ) =24.78 (J·cm−3)0.5 and δ 2 ( [ C 8 C 1 im ] Br ) = 24.23 (J·cm−3)0.5 at room temperature (298.15 K). At the same time, the Hansen solubility parameters of the four [CnC1im]Br ILs were simulated by using the Hansen Solubility Parameter in Practice (HSPiP) at room temperature (298.15 K). The results were as follows: δ t ( [ C 5 C 1 im ] Br ) = 25.86 (J·cm−3)0.5, δ t ( [ C 6 C 1 im ] Br ) = 25.39 (J·cm−3)0.5, δ t ( [ C 7 C 1 im ] Br ) = 24.81 (J·cm−3)0.5 and δ t ( [ C 8 C 1 im ] Br ) = 24.33 (J·cm−3)0.5. These values were slightly higher than those obtained by the IGC method, but they only exhibited small errors, covering a range of 0.01 to 0.1 (J·cm−3)0.5. In addition, the miscibility between the IL and the probe was evaluated by IGC, and it exhibited a basic agreement with the HSPiP. This study confirms that the combination of the two methods can accurately calculate solubility parameters and select solvents.

Quantitation of anticonvulsant drugs in serum by gas-chromatography on the stationary phase SP-2510.

1978 ◽  
Vol 24 (3) ◽  
pp. 483-485 ◽  
Author(s):  
W Godolphin ◽  
J Thoma
Keyword(s):  
Gas Chromatography ◽  
Liquid Chromatography ◽  
Stationary Phase ◽  
Serum Cholesterol ◽  
Anticonvulsant Drugs ◽  
Gas Liquid Chromatography ◽  
Column Packing ◽  
Extraction Procedures

Abstract A new column packing, SP-2510 DA (Supelco, Inc., Bellefonte, Pa. 16823), is an excellent stationary phase for the determination of a wide variety of anticonvulsant drugs by gas--liquid chromatography without derivatization. However, when uncomplicated extraction procedures are used, serum cholesterol interferes with the determination of primidone. By the simple expedient of adding a short "pre-column" containing another phase (SP-2250 DA) the problem is overcome.

Inverse gas chromatography. 3. Dependence of retention volume on the amount of probe injected

1985 ◽  
Vol 18 (11) ◽  
pp. 2196-2201 ◽  
Author(s):  
Petr Munk ◽  
Zeki Y. Al-Saigh ◽  
Timothy W. Card
Keyword(s):  
Gas Chromatography ◽  
Inverse Gas Chromatography ◽  
Retention Volume

The use of gas-liquid chromatography to determine activity coefficients and second virial coefficients of mixtures I. Theory and verification of method of data analysis

1966 ◽  
Vol 295 (1442) ◽  
pp. 259-270 ◽  
Keyword(s):  
Numerical Integration ◽  
Retention Volume ◽  
Simple Extension ◽  
Gas Liquid Chromatography ◽  
Local Pressure ◽  
Integration Procedure ◽  
Carrier Gas ◽  
Wide Range ◽  
Analytical Integration ◽  
Numerical Integration Procedure

This paper reformulates the differential equation describing the local elution rate in a g. l. c. column in terms of the local pressure and the carrier gas outlet flow rate. Analytical integration for an ideal carrier gas suggests an accurate method for extrapolating a function of the retention volume linearly to zero pressure, where the intercept V ° N is simply related to the thermodynamic activity coefficient of the solute (1) in the stationary liquid (3) and the gradient β gives B 12 for the mixture solute + carrier gas (2). We argue that a simple extension of the method should apply also, with fair accuracy, to a non-ideal carrier gas. We support this argument with data obtained by a numerical integration procedure which gives retention volume in terms of specified V ° N and B for a range of inlet and outlet pressures. The reliability of the numerical integration procedure is established by comparing results for the ideal gas case with the results of analytical integration. The retention volumes obtained by numerical integration for a non-ideal carrier gas are then treated as ‘experimental’ observations, using in addition to our extrapolation procedure, two previously published procedures. Our procedures are consistently more successful than the others and recover accurately the V ° N originally specified over a wide range of flow conditions, even when the carrier gas shows large deviations from ideality. In the case of β , our method is significantly in error only when the carrier gas deviates largely from ideality in a low pressure column with large pressure drop. A simple refinement of our method is satisfactory for even this case.

Determination of the loss of stationary phase in gas-liquid chromatography from the change in retention volume

1976 ◽  
Vol 128 (1) ◽  
pp. 35-43 ◽  
Author(s):  
Anne-Marie Olsson ◽  
Lennart Mathiasson ◽  
Jan Åke Jönsson ◽  
Lars Haraldson
Keyword(s):  
Liquid Chromatography ◽  
Stationary Phase ◽  
Retention Volume ◽  
Gas Liquid Chromatography
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