High-performance liquid stationary phase for gas chromatography

 

(57) Abstract:

Usage: gas chromatography, application of the sorbent, while the analyses of the low-boiling hydrocarbons. The essence of the invention: liquid crystal as stationary phase using 2,3,5,6-tetrahedral oxyhydroxide. 2 Il., table 2.

The invention relates to gas chromatography, namely, the liquid crystal stationary phases for the separation and analysis of organic mixtures containing low-boiling linear and cyclic hydrocarbons.

Known use as a nematic liquid crystal stationary phase n, n'-methoxyethoxyethoxy for the separation and analysis of mixtures of aromatic hydrocarbons. However, this stationary liquid phase is characterized by low selectivity in the separation of organic mixtures containing blastocytosis linear and cyclic hydrocarbons. Known as stationary phase based on discotic liquid crystals triphenylene series. However, it also has poor selectivity and efficiency in the separation of linear and cyclic hydrocarbons with similar boiling points (Z. Witkiewicz, Szule J.//J. Chromatogr., 1984, v. 315, R. 14 the C class derived hexacosanol, namely exaggerated.anorexia (Z. Witkiewicz, Goca B.//J. Chromatog., 1987, v. 402, R. 73-85). Its disadvantage is the lack of selectivity of separation bizcochada linear and cyclic hydrocarbons.

The purpose of the invention to provide an improved chromatographic characteristics of the stationary phase liquid crystalline nature, used to separate bizcochada linear and cyclic hydrocarbons, expanding the range of stationary liquid crystalline phases and applications of discotic liquid crystal - 2,3,5,6 - tetrahydrogestrinone.

This objective is achieved in that, as a stationary phase liquid crystalline nature is used 2,3,5,6-tetrahydroaminoacridine (THIGH) - discotic liquid crystal.

THOUGH as stationary phase for gas chromatography was not used and use it as a stationary phase clearly follows from its properties and characteristics.

Known application THOUGH as the object for the study of discotic mesomorphism and as anti-friction and anti-wear additives for lubricating oils.

To assess S="ptx2">

Were tested following stationary phases: 1) 2,3,5,6-tetrahydroisoquinoline - THOGH-1 - the declared object 2) Exaggerated.anorexia - analog (literature data) 3) Polymethylsiloxane liquid - equivalent.

Stationary phase in an amount of 10 wt. % put on a solid inert carrier W chromo-sorbitol from solution in pentane. Next, we analyzed the test mixture comprised of: hexane, octane, Nanan, cyclohexane, cyclooctane, benzene, o-xylene. The tests were carried out on the chromatograph Color-152 with a flame ionization detector, column, glass, length 3 m, inner diameter 3 mm, carrier gas - helium, the speed of the carrier gas 30 ml/min Temperature chromatographic determination in the cycle of heating the column 60 - 95aboutSince, in the refrigerating cycle 95 - 59aboutC. In the cycle of heating during the transition from one temperature to another column stand for 30 minutes, in the refrigerating cycle is 60 minutes Selectivity of the stationary phase was evaluated by the values of the selectivity coefficients () for pairs of compounds:

= , where t'Rthe retention time of the test compounds, the first component under test pair;

tRothe retention time of methane;

t"Rthe retention time of the test compounds is joining the studied stationary phases.

From the data table. 1 shows that the proposed stationary phase THOGH-1 shows the best chromatographic characteristics of selectivity than the analogues 2, 3. The coefficient of the selectivity of test compounds in pairs increases with a minimum of 2.26 and a maximum of 62% compared to similar 2. Compared to similar 3 the difference is even more significant, the coefficient of the selectivity increases by 1.6 - 1.8 times, i.e. almost 70% to 90%.

The effectiveness of using the proposed object instead used stationary phase polymethylsiloxane fluid and analog 2 is confirmed by the definition of the coefficient of capacitance of the column (K) for n-xylene in the cycle of heating chromatographic column (PL. 2).

The capacity factor was calculated by the formula

To = t'R/toRwhere K - the coefficient of capacity;

t'Rthe retention time of n-xylene;

toRthe retention time of methane.

From the data table. 2 that the maximum value of column capacity factors in the cycle of heating observed in a much larger temperature range for the proposed facility compared to the similar.

In Fig. 1 shows a chromatogram of a test mixture on hadigny phase - polymethylsiloxane fluid; refer to Fig. 1-2: 1 - hexane; 2 - benzene; 3 - cyclohexane; 4 - octane; 5 - cyclooctene; 6 - nonen; 7 - o-xylene.

The use of 2,3,5,6-tetrahydrogestrinone as high-performance liquid stationary phase for the separation and analysis of organic mixtures containing low-boiling linear and cyclic hydrocarbons.

 

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