Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
  • G01N30/90—Plate chromatography, e.g. thin layer or paper chromatography
  • G01N30/92—Construction of the plate

Definitions

• the invention relates to separating materials for planar chromatography which have porous separating agent layers of small thickness and which are suitable for separating substances on an nL scale.
• particulate separating agents which can be spherical or irregular in shape, have so far been applied to a support, with auxiliaries such as e.g. Binder, fluorescent indicators, reflection enhancers or the like can be added to the layer.
• auxiliaries such as e.g. Binder, fluorescent indicators, reflection enhancers or the like.
• Such additives are known to the person skilled in the art. It does not seem possible to reduce the layer thickness of the release agent layer to less than 50 ⁇ m.
• the invention relates to separation materials for thin-layer chromatography consisting of a base support and a release agent layer obtainable by the following steps: a) cleaning the base support; b) applying a liquid film containing a polysilicic acid ester to a base support; c) placing the carrier with the liquid film in an atmosphere which causes the hydrolysis and further polymerization of the polysilicic acid ester; d) hydrolysis and further polymerization of the polysilicic acid ester at constant temperature; e) washing the silica layer; f) drying the silica layer.
• the invention also relates to separation materials with the features mentioned, the silica gel surface of which is derivatized with separation effectors.
• the invention also relates to the use of separation materials with the features mentioned for the thin-layer chromatography separation of at least two substances.
• the invention relates to processes for the production of separating materials with the following process steps: a) cleaning the base support; b) applying a liquid film containing a polysilicic acid ester to a base support; c) placing the carrier with the liquid film in an atmosphere which causes the hydrolysis and further polymerization of the polysilicic acid ester; d) hydrolysis and further polymerization of the polysilicic acid ester at constant temperature; e) washing the silica layer; f) drying the silica layer; in preferred embodiments process step b) is carried out by spraying on the solution or the liquid film is applied by first applying the liquid at one point and then rotating the carrier around the application point, the axis of rotation being perpendicular to the surface of the base carrier, or by spreading the liquid film with a roller squeegee.
• Figure 1 shows the separation of a dye mixture in a schematic and enlarged view.
• the separated dyes A, B and C are shown on the separating material (1) on four tracks; (2) marks the location of the eluent front.
• the original size of the separating material is approx. 14 x 56 mm; Further experimental details can be found in the description (application example A).
• Base supports in the sense of the present invention essentially mean the base supports customary for thin-layer chromatography, such as, for example, plastic or metal foils, but in particular glass plates. Because of the miniaturization of the separating materials according to the invention, other base supports can also be used in principle, which have hitherto consisted of conventional thin-layer materials - 4 -
• the separating agent layer in the case of separating materials for thin-layer chromatography consists, for example, of particulate silica gel, which can be modified with separation effectors, and further additives, such as e.g. Can contain binders, fluorescent dyes or reflection enhancers.
• the release agent layers according to the invention consist of silica gel, which is generated in situ by hydrolysis and polymerization from polysilicic acid esters.
• the separating layers according to the invention can also contain conventional additives; for example, they can be modified with separation effectors or, for example, a fluorescence indicator can be incorporated into the release agent layer.
• the alcohol component of the polysilicic acid esters used according to the invention are derived from C 1 -C 5 alcohols, in particular from methanol, ethanol, n-propanol or i-propanol.
• the average molecular weight of the polysilicic acid esters used according to the invention is between 500 and 2000; preferably between 800 and 1500. Such polysilicic acid esters are commercially available.
• the polysilicic acid esters used according to the invention can be used as pure substances or as mixtures with different molecular weights and / or different alcohol components. It is also possible to use suitable polysilicic acid esters according to the invention
• Dilute solvents C.-C 5 alcohols, for example methanol, ethanol, n-propanol or i-propanol, have proven to be particularly suitable.
• the solvent is preferably selected so that the solvent and alcohol component of the polysilicic acid ester are the same.
• the content of polysilicic acid ester in the diluted solution should be at least 30% by weight. - 5 -
• the polysilicic acid ester must then be applied to the base support as a uniform liquid film.
• Two methods have proven particularly useful for this: a) A sufficient volume of liquid containing the polysilicic acid ester is applied to the center of the base support; the base carrier is then rotated about the axis which passes through the application point and which is oriented perpendicular to the surface of the base carrier, so that a uniform film of liquid is formed. ) The polysilicic acid ester is undiluted or diluted to the
• Base carrier sprayed on Other methods are, for example: Application using a technique similar to screen printing or using a roller squeegee.
• the atmosphere in which the further hydrolysis and polymerization of the polysilicic acid ester takes place contains, in addition to water vapor, either ammonia or hydrochloric acid.
• Such an atmosphere can be created, for example, by introducing the base support provided with the liquid polysilicic acid ester into a chamber in which there is smoking hydrochloric acid in an open vessel, and then subjecting the chamber to superheated steam.
• the polymerization of the polysilicic acid esters takes place preferably at 15 to 80 ° C, in particular at 40 to 60 ° C, and takes 3 minutes to one hour depending on the temperature.
• the separating material is dried at 15 to 120 ° C. using customary methods (depending on the temperature, 5 to 30 - 6 -
• the separating layers obtained according to the invention have a thickness of 2 to 20 ⁇ m, in particular 4 to 10 ⁇ m.
• the mesopores which arise in the process according to the invention can be enlarged using customary methods, in particular also by treatment with aqueous ammonia solution.
• the silica gel layer on the base support can also be derivatized using conventional methods.
• separation effectors such as Ionic groups for ion exchange chromatography or hydrophobic groups for reversed phase chromatography were introduced.
• Such derivatization processes and suitable separation effectors are known to the person skilled in the art and in manuals such as packings and stationary phases in chromatography techniques (KK: Unger ed .; Marcel Dekker, New York and Basel (1990)) or porous silica (KK Unger ed .; Elsevier, Amsterdam , Oxford, New York (1979)).
• derivatization methods are particularly suitable, as are disclosed in DE 27 12 113 and DE 28 09 137.
• a carrier glass plate 20 x 20 cm is cleaned with sodium hydroxide solution and then with Extran ® and finally with water. Then approx. 0.8 ml of a 50% (v: v) ethanolic solution of polyethoxysiloxane (medium
• the sprayed glass plate is placed in a closed room in which there is an open vessel with smoking hydrochloric acid, exposed to superheated steam (4 bar) and treated at 60 ° C for 30 minutes. The coated glass plate is then washed with water and dried. For use, the glass plate is cut into pieces of the desired format.
• a separating material for thin layer chromatography is obtained, the separating layer of which consists of porous silica gel with a thickness of approx. 5 ⁇ m.
• the release agent layer has a specific surface area of 410 m 2 / g and a specific pore volume of approx. 0.32 ml / g (nitrogen adsorption according to BET); this results in an average pore size of 3 nm.
• a separating material prepared according to Example 1 is immersed in a solution of methyloctadecyldichlorosilane (10% by weight in toluene) for 5 minutes. Then the release material is immersed in Various solvents rinsed: 5 minutes in toluene, 1 minute each in dichloromethane / methanol (1: 1; v: v), in acetone / water (1: 1; v: v) and in methanol. The plate is then dried in the hood for 30 minutes at room temperature and in the drying cabinet for a further 15 minutes at 120 ° C.
• 150 ml of fuming hydrochloric acid are placed in a conditioning chamber.
• the closed chamber is preheated to 60 ° C in the drying cabinet (1 hour).
• the chamber is removed from the drying cabinet and water vapor is added to the chamber (open the shut-off valve slightly, duration approx. 5 seconds).
• a washed glass plate (10 x 20 cm) is cleaned with ethanol and dried.
• the glass plate is then pulled off with 400 ⁇ l of polyethoxysiloxane (average molecular weight 1000) and with a 12 ⁇ m roller doctor.
• the coated glass plate is placed on a styrofoam plate (20 x 20 cm) in the conditioning chamber and heated at 60 ° C for 30 minutes.
• the TLC plate is then washed with water and air-dried.
• the silica gel layer has a layer thickness of 12 + 1 ⁇ m and adheres firmly to the glass plate.
• the silica gel layer can, as described in Example 2, be derivatized. - 9 -
• Example 1 is applied in four lanes with a Hamilton syringe, 50 nL each of a dye mixture containing 0.1% by weight of violet I, nitro real blue 2B and sico-fat blue 50401 N dissolved in toluene.
• Toluene is used as the eluent in a normal chamber (50 ml beaker with watch glass as lid) without chamber saturation.
• the running distance is 8 mm.

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• Physics & Mathematics (AREA)
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• General Health & Medical Sciences (AREA)
• General Physics & Mathematics (AREA)
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• Silicon Polymers (AREA)

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• 1998
  • 1998-02-11 DE DE19805395A patent/DE19805395A1/de not_active Withdrawn
• 1999
  • 1999-01-19 WO PCT/EP1999/000284 patent/WO1999041602A1/de not_active Ceased
  • 1999-01-19 JP JP2000531734A patent/JP4278866B2/ja not_active Expired - Lifetime
  • 1999-01-19 US US09/601,617 patent/US6395178B1/en not_active Expired - Lifetime
  • 1999-01-19 DE DE59915220T patent/DE59915220D1/de not_active Expired - Lifetime
  • 1999-01-19 EP EP99907383A patent/EP1055120B1/de not_active Expired - Lifetime

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