RU2037826C1 - Plate for thin-layer chromatography and method for its manufacturing - Google Patents

Abstract

FIELD: measurement technology; medical engineering. SUBSTANCE: method involves making flexible substrate layer with R_a= 0,8 - 15 mcm roughnesses by means of sandblast processing. Sand to be used is 0.3-0.7 mm fine quartz sand delivered by means of 0.06-0.5 mPa compressed air flow to the substrate surface moving with speed of 0.8- 1.4 m/min. Sand supply is performed through nozzles 8-10 mm in diameter, mounted 80-140 mm distant from the substrate surface. EFFECT: improved adhesive properties of substrate layer and coating; capability of being reusable. 4 cl

Description

 The invention relates to plates used in thin layer chromatography (TLC) and a method for their preparation.

 Known plate for TLC, consisting of a chromatographically active layer attached to a flexible inert base [1] The inert base is selected from the group consisting of polyester, vinyl, polyolefin, cellulose, polyamide films or metal foil. The chromatographically active layer contains a chromatographically active adsorbent selected from the group consisting of alumina, silica gel, kieselguhr, polyamide or cellulose powder, and a polymer binder selected from the group consisting of polyvinyl alcohol, mixtures of gelatin and polyvinyl alcohol, gelatin or cellulosic derivatives polyvinyl acetate, polyvinyl butyral, epoxy, melamine formaldehyde resins, etc.

 The described plate is obtained by preparing an aqueous suspension of a chromatographically active adsorbent and a polymer binder, applying the resulting mixture to a substrate and drying the coating, which, when cured, adheres firmly to the substrate.

As a prototype adopted plate for thin-layer chromatography and a method for its preparation. The chromatographically active layer consists of phosphors and highly dispersed silicon dioxide (aerosil) or highly dispersed aluminum hydroxide. The introduction of highly dispersed inorganic substances can be carried out either by initially mixing all the components in dry form and then adding water, or by adding additional components, dry or suspended in water, to the aqueous suspension of one of the components [2]
A thoroughly mixed mixture is applied in a thin layer on a substrate and dried, and then cut into plates of the desired size.

 The described plates are of high quality, provided by a sufficiently good adhesion of the chromatographically active layer to the substrate, which makes it possible to store and transport the plates for a long time without breaking them.

 However, such plates are intended for single use and, after analysis, are sent for disposal. In conditions of material shortage, after analysis, the plates can be treated with substances that destroy the analyzed organic substances in order to regenerate and then reuse or reuse them. However, in this case, the adhesion of the substrate and the coating deteriorates and its peeling is observed, which does not allow for repeated qualitative analysis.

 The invention solves the problem of providing multiple use of the plate for TLC without deterioration of its quality, achieved by improving the adhesion of the coating to the substrate.

In particular, the invention solves the problem of achieving such a degree of adhesion of the coating to the mylar film or aluminum foil, which makes it possible to conduct multiple (up to 8-10) qualitative analyzes on one plate. The indicated improvement in the adhesion of the coating to the substrate is ensured by the fact that according to the invention, a plate comprising a flexible substrate and a chromatographically active layer deposited on it has a surface roughness of the flexible substrate R _a = 0.8-1.5 μm.

 The plate is obtained by a method including the steps of preparing a suspension, applying to a flexible substrate, drying and cutting the plate, and in order to achieve the above roughness according to the invention, the surface of the flexible substrate is sandblasted before applying the suspension, quartz sand with a dispersion of mainly 0.3-0 , 7 mm, which under pressure of compressed air 0.06-0.15 MPa is fed onto a substrate moving at a speed of 0.8-1.4 m / min. The supply of quartz sand is carried out from nozzles with a diameter of 8-10 mm installed at a distance of 80-140 mm from the surface of the substrate.

 The invention is illustrated by a description of the experiments conducted, confirming the dependence of the resistance of the plates (and therefore, the reusability of use) from roughness.

 PRI me R s 1 and 2. The substrate material is mylar film. The coating material is an aqueous suspension of silica gel in silica sol with the addition of finely divided silica and phosphor. Roughness of the substrate: 0.3-0.5 and 0.6-0.7 microns. They tested lots of plates measuring 100x100 mm in an amount of 10 copies. The number of analyzes performed on each plate without breaking the coating was 1.2 and 2.3, respectively.

 PRI me R 3. The material of the substrate and coating as in example 1. The roughness of the substrate is 0.8-1 microns. A batch of plates measuring 100 x 100 mm in an amount of 10 copies was tested. The number of analyzes performed on each plate without breaking the coating is 6–9.

 PRI me R 4. The substrate material is mylar film. The coating material is an aqueous suspension of silica gel in silica sol with the addition of finely dispersed alumina. The roughness of the substrate is 1.2-1.4 microns. A batch of plates measuring 100 x 100 mm in an amount of 10 copies was tested. The number of analyzes performed on each plate without breaking the coating is 9-12.

 PRI me R 5. The substrate material is aluminum foil. The coating material as in example 1. The surface roughness of 0.8-1.1 microns. A batch of plates measuring 100x100 mm in an amount of 8 copies was tested. The number of analyzes performed on each plate without fracture was 10.11.

 To achieve the indicated roughness of the flexible substrate, before applying the suspension, the surface was sandblasted with quartz sand with a fineness of 0.3-0.7 mm by feeding it to a moving substrate under a pressure of compressed air of 0.06-0.15 MPa. In this case, quartz sand is supplied from nozzles with a diameter of 8-10 mm installed at a distance of 80-140 mm from the surface of the substrate.

 Obtaining a rough substrate for reusable plates for TLC using the described method is possible, for example, using an installation including unwinding and winding stations with a flexible substrate, an upper sand feed hopper having nozzles and connected to a compressed air supply system, a lower sand hopper and a conveyor for sand supply to the upper hopper enclosed in a casing with exhaust ventilation.

 Using the setup described above, a series of experiments was carried out, with the help of which the optimal parameters of specific modes of the claimed method were determined. To give the surface of the substrate the required roughness, quartz sand was used, which is more than 80% composed of particles 0.3-0.7 mm in size and up to 20% of smaller fractions.

PRI me R 6. The distance from the end of the nozzle to the surface of the substrate is 100 mm Turn on the electric drive of the substrate, the speed is 1 m / min. The pressure at the inlet to the nozzle was 0.1 MPa, sand consumption 2.5 kg / min. A roughness of the film R _{a of} 0.9-1.2 μm was achieved.

PRI me R s 7-11. Repeat the conditions of example 6, changing the distance from the ends of the nozzles to the surface of the film. The dependence of roughness on the distance to the film surface: Distance, mm R _a , μm 60 1.8 80 1.5 100 1.2 130 0.8 150 0.4
At a distance of less than 70 mm, unwanted traces of the trajectory of movement of large sand particles are clearly visible on the surface.

PRI me R s 12-16. The experimental conditions as in example 6. Change the pressure of the compressed air at the inlet to the nozzle. The dependence of roughness on pressure: P, MPa R _a , μm 0.05 0.3 0.06 0.7 0.08 0.8 0.15 1.2 0.18 1.4
At pressures above 0.15 MPa, the dullness and roughness of the film increases; undesirable traces of the trajectory of sand particles are noticeable.

PRI me R s 17-20. The experimental conditions as in example 6. Change the speed of the substrate. The dependence of roughness on the speed of movement of the substrate: V, m / min R _a , μm 0.8 1.4 1.2 1.0 1.4 0.4 1.55 0.06
Similar results were achieved by sandblasting an aluminum foil substrate.

 The suspension obtained for the plates obtained by the described method is applied by known methods to a suspension, and then the coating is dried. After drying, the coated film is cut into plates of the required size. The sequence of operations for the manufacture of plates for TLC may be different. For example, the substrate prepared as described above is cut into plates of the required size, then they are coated and dried.

Claims (4)

 1. Plate for thin layer chromatography, comprising a flexible substrate and a chromatographically active layer deposited on it, obtained by drying an aqueous suspension of silica gel in silica sol with additives, characterized in that the surface of the flexible substrate has a roughness of R 0.8 1.5 μm.  2. A method of manufacturing a plate for thin layer chromatography, including preparing a suspension, applying a suspension to a flexible substrate and cutting a plate, characterized in that before applying the suspension, the surface of the flexible substrate is treated to obtain a roughness of R 0.8 - 1.5 μm by applying quartz to it sand from nozzles under pressure of compressed air.  3. The method according to p. 2, characterized in that they use quartz sand with a dispersion of 0.3 0.7 mm and feed it under a compressed air pressure of 0.06 - 0.15 MPa from nozzles with a diameter of 8 10 mm installed at a distance of 80 140 mm from the surface of the substrate.  4. The method according to PP. 2 and 3, characterized in that the supply of quartz sand is carried out on a substrate moving at a speed of 0.8 to 1.4 m / min.