SU1629268A1 - Process for preparation capillary quartz column - Google Patents

Abstract

The invention relates to gas capillary chromatography and can be used to analyze both inorganic substances and complex multicomponent mixtures of organic compounds. In order to increase the adhesion of the coating to the glass surface and increase the mechanical strength of the column, a quartz capillary column is made by pulling a capillary out of a thermally softened quartz tube deposited on its outer surface of a protective coating of nitrogen-containing polyheteroarylene and heat-treated the coating at 550-600 for 1 -3 s in an inert atmosphere. Mechanical strength — more than 150 bends over a length of up to 100 m; adhesion — application of force is required to peel the blade. 2 Il. 1 tab. $

Description

The invention relates to chromatography, primarily gas capillary chromatography, and can be used to analyze both inorganic substances and complex multicomponent mixtures of organic compounds.

The aim of the invention is to increase the adhesion of the coating to the surface of the glass and to increase the mechanical strength of the column.

FIG. 1 shows an installation for drawing a capillary; FIG. 2 - device for short-term high-temperature exposure.

The capillary drawing unit contains a quartz billet feeding mechanism 1, an oxygen-hydrogen burner 2, a spinneret 3 seconds. polyimide varnish, a capillary tube 4, a tube furnace 5, a high-temperature device 6, a winding receiving drum 7.

The device for short-term high-temperature exposure includes an argon supply pipe 8, an inlet pipe 9, a discharge pipe 10, a resistance heater 11.

The method is carried out as follows.

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OE

Do

The quartz tube-z. Is supplied to the flame of the oxygen-hydrogen burner 2 by means of the feeding mechanism 1, after softening, a capillary tube 4 is drawn from it, which is then passed through the die plate 3 filled with polyimide lacquer PLI-2. A capillary with a layer of lacquer applied on its outer surface enters the tube furnace 5, the temperature of which is 100–200 ° C, which ensures the removal of the solvent and the curing of the coating. From the furnace 5, the capillary is pulled through the device 6 for short-term high-temperature exposure j, which is a quartz tee, in which argon of the h brand is continuously blown through the pipe, and through the other two pipes it is heated briefly by the resistance heater. Then, after removing the temperature gradient, the capillary is under argon atmosphere for some time and then rolled up onto the receiving drum 7, and after deposition of the quartz liquid to the internal surface of the stationary liquid phase is ready for use.

The quality of the KKK was evaluated by the mechanical bending strength and ease of separation of the polyimide coating from the glass surface, which characterizes the adhesion of the polyimide to glass. The mechanical bending strength is determined by measuring the length of a capillary, which is broken off when a sample is tested by winding it on a round rod with a diameter of 7 mm and the number of repeated windings of a capillary with a length of 200 mm on a rod with a diameter of 15 mm. The ease of separating the protective polyimide coating is determined by peeling and scraping the polymer film with a sharp blade. This operation is performed under a microscope at a magnification of 20x.

Example 1. From the workpiece from

high-purity synthetic quartz glass with an outer diameter of 12mm

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and a wall thickness of 1.5 mm, the capillaries are pulled out. Capillary drawing speed 6 m / min. The protective polymer coating is obtained from the GOSHK-2 varnish solution. The temperature of the tube furnace is 115 ° C, the temperature of the furnace of the quartz reactor is 550 C. The residence time in the high temperature zone is 3 s. As a result, a flexible quartz capillary is obtained with the following characteristics: external capillary diameter 0.5 mm, wall thickness 0.065 mm, protective coating thickness 0.012 mm.

The table presents examples with different parameters of the method and properties of coatings.

The table shows that the quality of the KKK processed by the described method with a protective polyimide coating significantly improved the quality of the quartz capillary made without it by a known method.

The use of the invention allows to increase the mechanical strength of the KKK as a whole, reduces the likelihood of their failure during operation, makes it possible to use natural quartz glass instead of synthetic glass, to reduce the background during further chromatographic analysis caused by incomplete chemical processes and the presence of non-removed polymerization products in the coating.

Claims (1)

Invention Formula A method of making a quartz capillary column for chromatography by drawing a capillary out of a thermally softened quartz tube, applying a protective coating of nitrogen-containing polyheteroarylene to its outer surface and then heat treating it with the aim of increasing adhesion of the coating to the surface glass and increase the mechanical strength of the column; the coating is heat treated at 550-600 ° C for 1-3 seconds in an inert atmosphere. THICKNESS of coating 0,025 mm 550-0, 007 1  3 80 150 Force is required Over 150 Over 150 Force is required " a l . CC SW sh w | TG7 G / 1 .2 fO E lr