DE2125428C2 - Chromatographic packing and process for its manufacture - Google Patents

Description

The invention relates to chromatographic packings in which silanols are chemically bonded to a substrate and are polymerized to a stationary organic phase, as well as a process for their preparation.

An earlier attempt to chromatographic a stationary phase by esterification of silicic acid Chemically binding carriers to a substrate with alcohols is described by 1. Halasz and I. Sebastian in »Angewandte Chemie International Edition «. Volume 8 (! 969). Page 453. The Si-O-C bond that forms in the process however, it was hydrolytically unstable, and the product consisted of moiiomolecular films which only Adsorptive interactions, but no distribution interactions of the solute allowed.

According to a work by W. A. Aye and C. R. Hastings in Journal of Chromatography. Volume 12 (1969), p 319, one has polymolecular silicones in two series of procedures *: with chromatographic supports implemented. In the first series of process stages, dimethyldichlorosilane or methyltrichlorosilane is added to the Silicic acid carrier bound. In the second series of process stages, Organochiorsib.ne is sent to the called methylchlorosilanes bound. As highly reactive in both series of process stages Organochlorosilanes can be used, the extent of the reaction in any series of process steps difficult to control, which usually results in the formation of films of varying thickness leads. Furthermore, in the first series of process steps, methyl groups are applied to the substrate surface applied, thereby reducing the effective polarity of the packing. This is a clear disadvantage if polarity is desired Furthermore, the second set of process steps does not permit use volatile organochlorosilanes, and thereby the choice between the resulting stationary phases limited. Furthermore, those organochlorosilanes that would be needed as starting materials react to to apply certain functional groups (e.g. amino groups) to the surface with themselves and destroy them therefore itself. Finally, the remaining active surface sites had to be used before use deactivated for chromatography. When deactivated, a silicic acid ester remains, the thermally and hydrolytically so unstable that it is required for gas chromatography "bleeding" occurs at higher temperatures. J5

From Noil. "Chemie und Technologie der Silicones", 1968, pages 83 to 85 is the spontaneous condensation of Organosilanols known. The condensation of organosilanols on substrates is known from loc. Cit., Page 524.

From Journal of Chromatography, 22, (1966) pages TS through 28 and 37 (1968). Pages 97 to 98 disclose silicone chromatography materials. With these materials, however, there is presumably no bond between the "inert" and the stationary phase. Apparently, with these materials there is only a polymerized coating of organic material on the carrier surface by WA Aye and CR Hastings (loc. cit.), page 320, paragraph 5. It says there that in the case of chromatography materials as described in the last-mentioned publications, the organic phase can be extracted completely from the solid support and therefore no chemical bonds exist between the two phases Such materials are disadvantageous due to the lack of bonding between the support and the stationary phase.

The invention is based on the object of providing a chromatographic packing the one organic stationary phase by means of a hydrolytically and thermally stable bond chemically is bonded directly to a silicon or aluminum-containing substrate, with the thickness and porosity of the forming, chemically bound stationary phase can be controlled.

This object is achieved by the subject matter of the invention as defined in the patent claims.

By selecting the radicals R4 and R3 '(if the latter is not a hydroxyl group), the chemical Bound stationary phase with a wide variety of functional groups, so that you can have a chromatographic Packing of any selectivity is obtained, depending on the requirements of the chromatographic in question Separation one can get packs which in their properties from extremely polar to « non-polar vary

The thickness of the stationary phase that forms is controlled with the aid of the quantities of the starting materials. So a bonded stationary phase can be applied in a layer that is controllable monomolecular in thickness or is polymolecular. In particular, a polymolecular layer of a predetermined thickness can be used, which allows precise diffusions to bind to the substrate. t> o

By reacting mixtures of the above-mentioned starting compounds with the surface and Co-condensation gives "mixtures" suitable for special purposes. The component; this Mixtures are determined by controlling the concentrations of the initial reactants.

A particularly valuable type of such mixtures are those with the aid of which the degree of crosslinking in the bound and polymerized stationary phase can be controlled. Higher concentrations of b5 starting materials in which Rj 'is a hydroxyl group, leading to a higher degree of crosslinking, which is of particular who ^{first for} gas chromatography is. On the other hand, higher concentrations of compounds in which Rj 'does not mean a hydroxyl group lead to a lower degree of crosslinking, which for the

Liquid chromatography is suitable. Extremely high degrees of crosslinking are obtained when one of these Compounds (the compound in which R / represents a hydroxyl group, or the compound in which Ri ' means no hydroxyl group) is used on its own.

If packings with the chemically bound stationary phase are used in liquid chromatography, there is no need for guard columns or the precaution of the carrier with the stationary phase. Furthermore, due to the homogeneous distribution of the stationary phase on the surface of the support, high column efficiencies are maintained. This bound stationary phase results in greater durability of the chromatographic columns and eliminates many difficulties which result from the loss of partition liquid in the operation of the conventional liquid-liquid chromatographic columns.
H) Substrates for gas chromatography with the chemically bound liquid stationary phase have a very low vapor pressure. This extends the life of the chromatographic column and keeps the "noise level" in the detection system due to the "bleeding out" of the stationary phase to a minimum. Furthermore, the packings have a very high heat resistance, as is preferred for gas chromatography.
5 To further explain the invention, reference is made to the drawings.

Fig. 1 is a schematic representation of a cross section through a preferred chromatographic Carrier material.

F i g. Figure 2 is a schematic cross-section through a polymeric stationary phase chemically bonded to a substrate.
.Ό F i g. 3 shows the chemical structure of the polymeric stationary phase.

Fig. 4 shows part of the liquid chromatographic separation of sulfonamides according to the invention.

F i g. Fig. 5 shows comparative curves for the relationship between the theoretical floor height and the carrier speed in liquid chromatography using the invention and the prior art > s technology.

6 is a diagram of the liquid chromatographic separation of thiohydroxamates according to FIG Invention.

F i g. 7 is a diagram of a liquid chromatographic diagram. cn separation in a column with a bound "Nitrile" phase according to the invention.

FIG. 8 is a diagram of a programmed temperature gas chromatographic separation in a bound "ether" phase according to the invention.

9 compares several chromatographs and shows the selectivity of the bound "ether" phase according to FIG of the invention in gas chromatography.

F i g. 10 shows, in the form of a diagram, the relative "bleeding" speed of a device within the meaning of the invention Bound stationary "nitrile" phase compared to a prior art chromatographic column Technology.

Fig. !! FIG. 13 shows a thermogravimetric curve for a chemically bonded "nitrile" packing according to FIG Invention.

Fig. 12 is a diagram of a gas chromatographic separation of aromatic hydrocarbons with -to a bound »Nilrilw phase.

Chromatographic packing with chemically bound organic stationary phases can be used the most varied of functional groups are produced, whereby one of the most varied of chromatographic Can achieve selectivities. Bound phase packs for gas and liquid chromatography can be produced on a wide variety of substrates. The surface of the silicon or The aluminum substrate is chemically reactive with silanols. Silicic acid-containing substrates will be preferred. Examples of suitable substrates are diatomaceous earth. Silica gel. Glasses. Sand. Aluminosilicates. Quartz, porous silica beads, clays and alumina.

When the substrate is in the form of a carrier (i.e., in particulate form), the form of the particles is not particularly crucial. Examples of particle shapes are rings. Polygons. Saddles, plates, fibers. Hollow tubes. Rods and cylinders. Spherical carriers are because of their regular and reproducible Behavior in the pack and the ease and ease of handling are preferred.

A preferred embodiment of a carrier is that in FIG. 1 shown carrier of controlled surface porosity (which is described in US Pat. No. 3,505,785 and is commercially available). This The carrier has an impermeable core 11, which is preferably made of glass or ceramic material, and a porous coating 15. made up of successively adsorbed individual layers 13 of microparticles composed. It consists of spherical individual particles that have a large number of flat surface pores 12. but do not have deep pores. In a particularly preferred embodiment, there are Microparticles made of SiO2 material. Such a carrier is referred to below as “carrier Z”.

It shows a regular and reproducible behavior in the pack. can be easily and conveniently Mi handle and possesses the properties necessary for performing at high speed and high efficiency Gas and liquid chromatography are required.

In discussing substrates, the terms "surface," "available surface," etc. on all surfaces that are accessible from the outside of the substrate. In Fig. I these include, for. B. the Surfaces within the pores 12.

t, -j Ofi i> > i it is advantageous if the surface of the carrier or substrate is initially heavily covered with metal-hydroxy- or is preferably occupied with - SiOH groups. This is best achieved by treating the Surface with an acid or base. The preferred method is to leave the wearer for several hours Heat on the steam bath with concentrated nitric acid or hydrochloric acid. Excess acid or base

should be washed off the surface before the carrier for the I'iusoi / ιιημ mil the silane keagen / ien is dried.

The /.iir i .r ^r / eugung of chemically bonded organic l'stationary hase reagents used are silanols of allgeneinen l'Ormel

ho

r;

Si

HO

R ₄

in which R] 'and R _{4 have} the meanings given above. These silanols are preferably made from silicic acid esters of the general formula

i \

Si

R.

made in the Ri and R_> Mean alkoxy groups. Rj denotes an alkoxy group or the radical R Γ and R.i has the above meaning.

A list of commercially available reagents is given in Table I. Table II lists other reagents which have not been commercially available up to now. These compounds have a wide variety of structures. she can be synthesized according to the general methods described in your work "Chemistry of the Silicones" by R. G. Rochow (John Wiley & Sons New York Publishers, 2nd Edition, 1951) are given.

10

15th

21)

Table I.

30th

reagent

Structural formula

γ-glycidoxypropyltrimethoxysilane

^ - (3,4-Epoxycyclohexyl) ethyltrimethoxysilane

^ Mercaptopropyltrimethoxysilane y-aminopropyltriethoxysilane

N-jS-aminoethyl-y-aminopropyltrimethoxysilane

[N-X-aminoethyl) -y-amino- (2-methyl) -propyl] -methyldimethoxysilane

y-methacryloxypropyltrimethoxysilane Vinyl tris (2-methoxyethoxy) silane dimethyl diethoxysilane Methyltriethoxysilane

Phenyltriethoxysilane Vtnyltriethoxysilane Amyltriethoxysilane Ethyltriethoxysilane Methyltrimethoxysilane CH-CH ₂ -O- (CH ₂ ) JSi (OCH ₃ ) J

(CH ₂ ) JSi (OCHj) ₃

HS (CH ₂ ) J Si (OCH ₃ ) J
NH ₂ (CH ₂ ) J Si (OC ₂ H ₅ ) J

HjN (CHj) jHNCH ₂ CH (CHj) CH ₂ -Si (OCHj) ₂

CH ₃ CH ₂ = CCH ₃ COO (CHj) ₃ Si (OCH ₃ ) J

C ₂ H ₃ Si (OCjH ₄ OCH ₃ ),

(CHj) ₂ Si (OC ₂ H ₅ ) J.

CH ₃ Si (OC ₂ H ₅ ) J.

C ₆ H ₅ Si (OC ₂ H ₅ ),

C ₂ H ₃ Si (OC ₂ Hj) ₃

C ₅ H _n Si (OC ₂ H ₅ ) J

C ₂ H ₅ Si (OC ₂ H ₅ ),

CH ₃ Si (OCHj) ₃

50

bO

continuation

reagent

Structural formula

Phenyltrimethoxysilane DiphenykMethoxysilane Viny 1-tris - (acetyl) -si lan 3-chloropropyl-trimethoxys: lan

N- (N-methoxycarbonylmethyl - ^ - ethylamino) -y-aminopropyl-trimethoxysilane

j8-cyanoethyl-triethoxysilane j8-cyanoethyl-methyldiethoxysilane

y- (aminocarbonyl) propyl-triethoxysilane "0-nitroethyl-triethoxysilane

(a, >> - Dihydroxypropyl) -methyl-dimethoxysilane

Methylsulfinylmethyl-triethoxysilane Perfluoropropyl trimethoxysilane

p-sulfamoylphenyl-methyl-dimethoxysilane

p-iMethoxycarbonyO-phcnyMrimethoxysüap.

L - (+) - p- [5- (methoxycarbonyl) -5-aminopentl-yl-sulfamoyl] -phenyl-trimethoxysilane

Methylsulfonylmethyl-triethoxysilane

C ₆ H ₅ Si (OCHj) ₃

CH ₂ = CHSi (OOCCH ₃ ),

CN (CH ₂ ^ Si (OCHjHs) ₃ CN (CHx) ₂ Si- (OC ₂ Hs) ₂ CH ₁

H ₂ NOC- (CHi) ₃ -Si (OC ₂ H ₅ ), O ₂ N-CH ₂ CH ₂ -Si (OC ₂ Hs) ₃

HOCH-CH ₃ -CH (OH) -Si (OCH ₃ ),

CH ₃

CHj-SO-CH ₂ -Si (OC ₂ Hs), F ₃ C-CF ₂ -CF ₂ -Si (OCH ₃ ),

NH ₂ SO ₂ -C ₆ H ₄ -Si (OCH,) ₂ CH ₃

CH ₃ OOC-C ₀ H ₄ -Si (OCH ₃ ); CH ₃ OOCCH (NH ₂ XCHi) ₄ NHSO ₂ C ₆ H ₄ -Si (OCHj) ₃

CHj-SO ₂ -CH ₂ -Si (OC ₂ H ₅ ),

If a silicic acid ester is used as a reagent, it must first be hydrolyzed to the silanol, which then takes place in the prepolymerization with the subsurface surface and then in the polymerization involved. There are circumstances that affect hydrolysis

1. a high or low pH (bases or acids).

2. soluble salts of certain metals, such as copper. Lead. Zinc and iron, and

3. the temperature.

In general, the silicic acid ester (if one does not want to produce aminosilanes) is hydrolyzed under acidic conditions, preferably at elevated temperatures. For the subsequent prepolycondensation, the hydrolysis is preferably carried out by heating the reagent to reflux temperature with an acid catalyst in a non-aqueous solvent which contains a multiple molar excess of water. The solvent should not only have a certain solubility for water, but it must also not react with the reagent, with water or with the catalyst (acid or base). The solvent should to 3OO ^C C. boiling in the range of 25 ctsva preferably from 50 to 20O ⁰ C.. Ethers such as tetrahydrofuran and dioxane. are satisfactory as a solvent.

The amount of to the non-aqueous solvent! ^The water to be added for the purpose of hydrolysis should contribute at least one third of the equivalents / es sikin reagent and need not exceed a 100-fold excess over this equivalent. Amounts of 1 equivalent to a 50-fold excess over 1 equivalent are generally sufficient. A very large excess of water prevents the subsequent

le Tcilp.il> condensation. The hydrolysis usually occurs with increased icuipcralurcn (preferably with • iiL-clcpunki of the nichi-waliiigen solvent) for a time period of min to several hours Inrchgcfiihi I.

This operation is generally carried out as long as it is the actual I lydrolvse ei ionlerich. mn a partial polycondensation. The water content and tier pi I value of the solution can be. If this is necessary for the partial polycondensation. aiii certain values can be set: the pII value λ is set to a range from i to b with ammonia, acetic acid or another catalyst.

The Teilpolykondensalion tier silanes before the reaction with the substrate is essential to the curve of a L'hemically bound stationary phase of the required thickness and porosity. The initiation of the polycondensation can be determined by adding a small amount of the silane-containing solution to water brings in. If there is a turbidity, it means that the prepolycondensation up to the point has advanced where part of the silar.rcagen is already insoluble in water and is therefore sufficient. on the other hand the prepolymerization should not proceed so far that the viscosity of the silane-containing solution is considerable increases.

The Umsei / ms vorpolykondcnsierten of silane with the substrate and the subsequent Fertigpolykouden- r> sation be carried out at temperatures of about 50 to J50'C, preferably from 100 to 250 'C. ^1. The times required for this procedure vary from a few minutes to several hours: usually times ranging from 1 to 3 skis for the preferred temperature range. the end.

Other methods by which silicic acid esters are prepolycondensed and with chromatographic substrates can be implemented are the following:

1. Prepare an acidic (pH 3 to 5) aqueous solution of the reagent. so that the lister becomes the appropriate Silanol compound is hydrolyzed. A suitable chromatographic substrate is added to the solution introduced and excess liquid filtered off. The mixture is first to temperatures below Heated to 100 ° C to initiate the polycondensation, and then heated to continue the reaction with the Carry out substrate surface and the polycondensation to the polymeric organic phase to complete.

2. The silicic acid ester is removed by evaporation from a suitable volatile solvent applied chromatographic substrate. Then the ester is hydrolyzed and prepolycondensed by humid air or water vapor is passed through the coated carrier. Then the Reaction with the surface and the polycondensation by heating.

3. The silicic acid ester contained in a volatile, non-reactive solvent such as tetrahydrofuran is made by adding aqueous hydrochloric acid and heating the mixture to reflux temperature hydrolyzed and prepolycondensed. The substrate is added to this solution. Then that becomes fleeting Organic solvents driven off at low temperature by vacuum distillation. One sets Toluene. Xylene or another suitable solvent in large excess / u to the wet powder and the azeoirope mixture of water and solvent is continuously distilled off. until implementation and the polycondensation is complete.

4. One can also see how the water crystallizes, which is the driving force in these reactions use chemical means. By adding reagents that react easily with water. like Dimethox in ypropan. the desired prepolycondensation is carried out. the llmsei / umg with the subsurface and the subsequent polycondensation.

Finally, extraction can be used to remove any silane that does not attach to-Ms Has bound substrate. The solvents used in this stage of the process should have a certain dissolving power for the unbound polycondensate, because this ensures that it is still on the polycondensate remaining on the substrate is actually chemically bonded to the substrate.

In the process stages of the prepolycondensation, the reaction and the polycondensation can also Mixtures of different types of silane molecules can be used. In this way you can be stationary Produce phases that have "mixtures" of different properties and are therefore suitable for special Separation processes are suitable.

A particularly valuable type of "mixture" is one that controls the degree of crosslinking in the polycondensation process. Packings for gas chromatography must generally have a highly crosslinked structure so that the polycondensate has the best resistance at high temperatures. Conversely, packings for liquid chromatography should have a less strongly crosslinked polymeric phase. This lower degree of crosslinking enables better penetration of the carrier and better penetration of the solute into the solvated polymeric structure. The previously bound stationary phases also have special chemical and physical properties insofar as they swell in certain solvents and form gelatinous, ordered structures that act as selective stationary gel phases. _w i

The extent of the crosslinking reaction is determined by adding alkoxysilicates of the general formula

R '

Si- ^ OR) ₁ R "

to the usual trialkoxysilicates of the general formula R - Si (OR ') j. By adding dialkoxysilicates in the reaction, the extent of the crosslinking is considerably reduced, since the other, to the Silicon atom-bonded group (R ") does not take part in the polymerization. By adding the modifying functional group R ″ can also have advantageous physical and chemical properties in the bonded phase Give properties.

As can be seen from the following exemplary embodiments, the reaction of the silicates with the The substrate surface depends very much on the amount of these reagents. Hence it is by controlling the initial Quantities of these reagents possible, the thickness of the film that forms on the substrate surface from the chemically bound stationary phase to control. If you z. B. wants to carry out a selective adsorption,

ίο you can make a monomolecular film. Used in common partition chromatography however, one has a substrate with a polymolecular layer.

In the latter case, the polymeric stationary phase basically consists of a three-dimensional porous one Network of repeating functional groups with a silane structure

M - O - Si bond

are chemically bound to the carrier surface. F. in a Scheniatischer cross-section through such a porous

The polymer structure is shown in FIG. 2, in which the substrate with 20. the chemically bound stationary! 'Hase with 2 !. part of the Polykon.densat ml! 22 and the pores are designated by 23. FIG . 3 schematically explains the novel structure of a piece of the polycondensation 22.

This chemically bound organic phase has an average thickness of JO to 10,000 A. preferably of 50 to 2000 A. This preferred range includes thicknesses sufficient to achieve the desired chromatographic Ensure interactions, but not so great that the efficiency of the chromatographic Column due to the resistance to mass transfer of the solute in the polymer Phase is impaired. The volume of the bound stationary phase should be around 20 to 95% and preferably consist of 35 to 75% pores. The polycondensate should be so porous that it is of the Carrier phase and the components of the sample can be penetrated, but it should also be sufficiently crosslinked to ensure that it has the required mechanical and chemical resistance.

Usually in chromatography the substrate is a particulate carrier. These Particles are coated with the stationary phase and packed in columns. According to the invention this stationary phase chemically bound to the carrier parts, which are then packed in columns in the usual way will. However, the invention is also applicable to other forms of chromatography. The stationary

j ', phase can be attached to a silica gel substrate. If you have a capillary tube without particulate When the carrier is used as a column, the stationary phase can be bound directly to the column wall itself will.

The substances in the bonded phase are also suitable for liquid distribution thin-layer chromatography. This method consists of having a suitable thin film adsorbent. like fine-grained Silica gel (with particle sizes of 5 to 10 μm) or finely divided diatomaceous earth, with one of the bound Polycondensate coated. This chroniatographically active material is thin in the usual way Layers carried out on tarpaulin. The plates are usually flat glass plates: others can be used Use fabrics and shapes. Mixtures of the compounds to be examined then graze on these thin-layer plates spotted and developed, following the usual procedures for on liquid adsorption based thin-layer chromatography. This method enables thin-layer chromatography to be carried out of relatively insoluble compounds with polar solvents in a liquid-liquid partition procedure. The methods of liquid-liquid thin-layer chromatography are im generally difficult, and chromatographic separations of poorly soluble compounds according to the Liquid-liquid dispersion methods are generally without the use of a chemically bound stationary one Phase impossible.

In liquid chromatography, the use of packings with bound stationary Phases further procedural advantages over the use of columns with the conventional mechanically retained liquid phases. Maxima can be collected and the component in question can Can be easily isolated for further identification by simply adding the volatile carrier system to the

v> evaporation brings. This is possible because the sample does not have a less volatile stationary phase is contaminated. which is usually present in such quantities in the usual liquid-liquid systems. that the wearer is saturated with it. It is also convenient to keep the drain from the detector for further use returned to the reservoir without a treatment in the circuit, since the carrier does not have a stationary phase needs to be brought into equilibrium.

1.1! Packings with chemically bound stationary phases are ideal for gradient elution and for flow programmed Liquid chromatographic separations. Polarity and flow velocity of the carrier solution can be changed gradually or continuously during an analysis, w ithout damaging the column. It is thus possible to produce a sample from components with very different Veitoilungsvcrhülliiisscii to be chromalographed in a single chronialographical process. that all components

tr, the sample eluted graze. The "regeneration" of the packing with the bound phase after a gradient elution III 1.11 can be done easily.

example 1

Production of an »ether« / »carrier Z« -
Packing for liquid chromatography

25 g of carrier Z (see above) with particle sizes of less than 40 µm and 150 ml of concentrated nitric acid are heated in a 250 ml beaker for 2 hours on the steam bath, stirring occasionally The carrier obtained in this way is washed acid-free by repeated suspension in distilled water. Then the material is air-dried on a glass frit vacuum suction filter and in a convection oven for 1 hour heated to 125 ° C.

A 100 ml round bottom flask is filled with 25 ml of fresh tetrahydrofuran (reagent grade), 6.65 ml of a solution of / -glycidoxypropyltrimethoxysilane in tetrahydrofuran at a concentration of 50 mg / ml and 0.75 ml 0.01 normal hydrochloric acid charged. This mixture is heated gently under the reflux condenser for 30 minutes. Then it will be the hydrolysis mixture was added to 25 g of the acid-treated carrier Z in a shallow evaporation dish. The volatile solvent is evaporated while stirring the mixture under a slow stream of nitrogen. The dry powder that remains is heated to 125 ° C. in a convection oven for 1 hour. After cooling down the mixture is transferred to a 500 ml round bottom flask containing 150 liters of dioxane. This mixture is 30 min heated to reflux temperature with gentle stirring. After decanting the solvent from dta; Support is added to 150 ml reagent grade methanol to the flask. The mixture thus obtained is Heated to reflux temperature for 10 min. The solvent is decanted and a further 150 ml absolute Methanol is added and the mixture is heated again! The solvent will again decanted and the remaining carrier dried in the air on a glass frying nutshell. Then the Carrier 30 minimally convection oven at 125 "CgCIrOCkIiCl.

The elemental analysis of the bound in this way carried out in a commercially available device "Ether" phase shows a carbon content of 035 and 033% and a hydrogen content of 0.062 and 2 => 0.063%. Assuming that the reaction takes place in the form given below, show the Results of the elemental analysis that there are 0.77% polymer on the carrier Z, which is 88% of theory is equivalent to.

(C ₂ HsO) ₅ -Si- (CH ₂ ) JO-CH ₂ CH - CH ₂

OH

H ₂ O (H ⁺ ) 1 I / ° 1> - Si - OH + HO - Si - Si (CHj) ₃ - O - CH ₂ CH - CH ₂

0 OH

—Si —OH

-H ₃ O

—Si —0 -

O-Si-OH

Si (CHj) ₃ -O-CH ₂ -CH -CH ₂

-H ₂ O

- Si - O O

- -Si (CH ₂ ), -

-Si- or

OH 0-CH ₂ -CH-CH ₂

5 —Si — G -

O — Si — OH

0 OH

Si- (CHa-O-CH ₂ -CH-CH ₂ -O-

Images of this material with the bound phase produced with the scanning electron microscope show no differences compared to the one used as the starting material. uncoated carrier Z, wor-15 This shows that the silane has reacted with the microparticle surface and the resulting stationary Phase does not clog the pores.

The porosity of the polymeric stationary phase itself results from determinations of the specific surface of the carrier Z. which is coated with the following amounts of bound "ether" phase:

SjKv.ifi.itiic surface.

ff Uncoated carrier Z 1.0

1 y> 0.38% "ether" 0.11

^ I I.Iä% "ether" 0.19

I I, b5% "ether" 0.42

% The rapid decrease in specific surface area that occurs when Carrier Z is in a small amount

si JO polycondensate is coated indicates that the polycondensate is initially in the pores between the

I microparticle reacts. The increase in the specific surface area that occurs when the amount of the

I carrier-bound polycondensation increases, indicates. that the bound stationary phase actually

% is porous. Furthermore, the stationary phase cannot be extracted with boiling organic solvents

'i | would normally have a considerable dissolving power for the polycondensate, from which it follows that the

; | J5 polycondensate reacted with the carrier Z surface.

% A typical chromatographic separation using a carrier Z-packing with bound

';; The "ether" phase is shown in FIG. This mixture of aromatic sulfonamides was converted into

r | a 1 m long and 2.1 mm wide column using 5% chloroform in hexane as support at 27 "C

I at a flow rate of 2.66 cm ^j / min. a column inlet pressure of 59.3 bar and a receiving

fij 40 sensitivity of the ultraviolet detector separated from 0.05 extinction (full-range value). The here used

• | Device is in a work by Joseph J. Kirkland in "journal of Chromatography Science". Volume 7 (19b9).

> M page 7.

: K The column with the bound »ether« -Phasc. which is used to separate these sulfonamides is

% not affected by the chloroform in the vehicle. If this separation in the usual way

: i | t5 had been made, the polar solvent would have a significant solvent power for the stationary

fif re liquid, from which the need for presaturation of the carrier with the stationary

j! Phase and the use of a column containing a packing with the stationary phase to the previous one

"% Balance. If the column is used with the bound phase, none is

p Precautions required.

fjf 50 The column with the bound "ether" phase proves to be stable at high carrier speeds. the

% Column was operated at a linear carrier speed of 20.8 cm / sec (column inlet pressure 206 bar,

Pf without any change in the chromatographic properties in subsequent use.

"4 shafts noticeable. Conventional columns for liquid-liquid chromatography can only be

] H can be maintained in their state with extreme difficulty, because at these flow velocities the

The high shear forces that develop lead to the loss of the stationary liquid phase from the packing.

• The efficiency of the dry-packed column with the bound »ether« phase is almost equivalent

■ that of comparable columns for liquid-liquid chromatography. the mechanically held one

.; stationary phases included.

F i g. 5 shows comparison curves for the relationship between the theoretical floor height (separation step height)

;. '; hi HIi ₁ I tier linear Triigci ^ oschwimligkoii for two columns that give us the same initial beams Z with

Particle sizes from Π to 44 μιιι are made. One column contains I "/» mechanically held /

"y-Oxydipropionitrile as stationary!" hase, while the other reveals 0.44% "ether" in the bound phase.

The theoretical body values for the column with the bound phase are slightly higher than those for the conventional liquid-liquid-ehmmilographic column, if acetophenone and benzyl alcohol are used as

ii '> used dissolved substances, of which acetophenone is significantly delayed and lien / ylalkohnl malJit.' / urüekgL-hiil-

\ ten will.

After the original values for the theoretical bowl height were obtained, the column was With the bound ether phase at kinetic pressure up to 54 3.2 har and linear carrier velocities

) is operated 40 cm / sec. Even under these extreme conditions, the column showed hardly any Ik-infiltration ; approx. which results from the points marked with 25 on the curves of I "i g. 5. Working with conventional : It is very difficult to use liquid-liquid-chromatographic columns at carrier speeds of 40 cni / sec. .veil this leads to losses of the mechanically retained stationary phase.

The special value of the bound »ether« phase for liquid chromatographic separations results in · ΐ iich also from Fig. 6. The synthetic mixture of thiohydroxamates given here was in a 1 m Approx. 2.1 mm wide column with carrier Z with grain sizes from 37 to 44 μιπ with a content of 0.94% Bound "ether" phase separated at 27 ° C with 10% chloroform in hexane as a carrier. By conventional Liquid-liquid chromatography classifies these compounds because of their polyfunctionality and their high level Difficult to separate polarity. They are strongly affected by most conventional stationary phases retained and require a polar carrier to take them to a convenient length of time to elute. The solubility of the stationary phase in this rapidly migrating polar carrier makes it extremely difficult to keep the performance of such a column constant. When using the package with the bound "ether" -Phassr there are no such difficulties, and one can wear any one Use polar device to chromatograph highly polar compounds.

Example 2

Production of a bound »// - cyan

ethyl "/" carrier Z "phase

25 ml of dioxane of reagent grade 5.5 ml e ": aer solution of / -Cyanäthyltriäthoxysilan in dioxane 1.iit a concentration of 70 mg / ml and 2 ml of 0.1 normal hydrochloric acid are mixed in a 250-m! -Round flask and The hydrolyzed mixture is poured onto 25 g (as described above, washed with acid) carrier Z with grain sizes below 37 μΓΠ and the solvent is driven off with constant stirring under the current of a warm air blower. The dry powder is removed for 1 hour . Heated in a convection oven to 150 ° C. The treated material is transferred to a 500 ml round-bottomed flask and refluxed with 200 ml of absolute methanol for 15 minutes min heated to reflux. the clear solvent was decanted and the support for another 15 min with 200 ml of fresh absolute methanol to the reflux temperature so heated. the clear solvent w ird again decanted and dried, the treated support on a Glasfrittermuische and heated for 30 minutes in a convection oven at 150 ⁰ C.

In the elemental analysis the bound phase gives 0.230 and 0.232% carbon, 0.032 and 0.034% Hydrogen and 0.087 and 0.089% nitrogen. These values show that the packing material is 0.83% silicone polymer (calculated on the basis of the structure given below), which corresponds to 90% of the theory. The r> Nitrogen adsorption (according to the flow method) gives a specific surface area of 0.44 m-Vg.

(CjH ₅ O), - Si - CHjCHjCN

ι? ^H

H ₂ O (H ⁺ ) II
> -Si-OH + HO-Si-CH ₂ CH ₂ CN

I I

OH

- Si — O-

O
Si-CH ₂ CH ₂ CN

-H, 0

An example of the selectivity of this packing with the bound "Nilril" phase for liquid sciroma -: =, tography is shown in FIG. 7. This synthetic mixture of relatively insoluble substituted acetanilides and sulfonamides is broken down into a mixture of equal parts of isopropyl chloride and hexane in about 5 minutes at a high flow rate. The value of this very strongly polar carrier in conventional liquid-liquid chromatography is questionable in view of its high degree of miscibility with most liquid stationary phases.It is noteworthy that this packing with the chemically bound nitrite ate compounds that can form hydrogen bonds , selectively withholds. Compounds with acidic - NH2 groups are particularly retarded, and certain substituted phenols such as 4-acetamidophenol. are also highly withheld.

The maximum for «-cyanacetanilide in FIG. 7 has a flow rate of 4.35 cm-Vmin theoretical tray height of 1.89 mm, which equates to 8.0 theoretical trays / sec (or 4, ö effective trays / sec) b5 When operating at a linear carrier speed of 1 cm / sec or less, this column shows for similar solutes have a theoretical floor height of less than 1 mm.

The efficiency of the liquid chromatographic columns with bound phase depends on the type and

the polarity of the carrier used. Columns with a packing with a bound "nitrile" phase show a poor efficiency when using hexane as a carrier. However, if the polarity of the If the carrier is increased, the efficiency of the column also increases (same distribution ratio of the dissolved Fabrics).

Example 3

Production of a bound »F.ster« - /
»Carrier Zw phase

IO

A 100 ml round bottom flask is filled with 25 ml of the purest dioxane. 2 ml of 0.1 normal hydrochloric acid and 4 ml of one Solution of v-methacrylo.xy-propyltrimethoxysilane in dioxane charged at a concentration of 70 mg / ml. The mixture is gently refluxed for 1 hour. This hydrolysis mixture is then in a flat Evaporation tray to 20 g of carrier Z with grain sizes below 37 μηι added and the solvent under mild

! ■> Stirring driven off under the current of a warning blower. The mixture is then heated to 150 ° C. in a forced-air oven for 1 hour. The treated support is transferred to a 500 ml round bottom flask containing 200 ml of absolute methanol. The mixture is heated to reflux temperature for 15 min, the clear solvent is decanted and this F.xirakiionsmcihode is repeated twice with 200 ml of fresh absolute methanol each time. After the iiriücn r.xtrükiir.n wire! (.! abiüirier the material on a glue line!; :: id ::: '. the l.tif! geiriiekne !. Then

: n the treated carrier is ^{dried for 30 min at 1 r} > 0 C in a convection oven.

The Klementaranalvse of the bound ·. · !! "I-lsier" -1 'Imsc gives a carbon content of 0.441% and a Hydrogen content of 0.077%, from which it follows that 1.07% of the polymer phase has the specified composition are on the carrier (which corresponds to %% theory based on the carbon analysis). the specific surface of the product, determined by nitrogen adsorption (according to the flow method) 0.52m-7g.

H ₂ O (H ⁺ )

- Si - (CH ₂ ), - OOC (CHj) = CH ₂

OH

I I

* - Si - OH + HO - Si - (CH ₂ ) J-OOC (CK ₃ ) = CHj
OH

-H ₂ O

—Si —O-

Si- (CH ₂₎ J-OOC (CHj) = CH ₂ OH

Example 4

Production of a bound "ether" phase for gas chromatography

vt 50 g of carrier Z with grain sizes of 105 to 149 μm (specific surface area 0.46 m-7gj determined by nitrogen adsorption are heated to 725 ° C. for 1 hour in a muffle furnace and then cooled in a desiccator . Treated nitric acid.

In a 100 ml round bottom flask, add 20 ml of highly pure dioxane, 10 ml of a solution of p'-glycidoxypropyltrimethoxysilane charged with a concentration of 100 mg / ml and 5 ml of 0.1 normal hydrochloric acid. That

The mixture is refluxed for 1 hour and then treated with acid as described above Carrier Z with grain sizes of 105 to 149 μπι added. The volatile solvent is taking out of the solution Stirring the mixture driven off under the flow of a hot air blower. The material thus obtained is Heated for 1 hour in a convection oven to 150 "C. The carrier is then placed in a 500 ml round-bottomed flask and with 200 ml of absolute methanol were heated to reflux temperature for 15 min with gentle stirring. The solvent

oo is decanting! and the extraction is repeated twice with 200ml fresh absolute methanol each time. That Material extracted three times is filtered off on a glass frit wrench, air dried and then JO min heated to 150X in an in-air oven. The elemental analysis of the sample shows 0.50% carbon, which is 1.1% Polymer on the carrier Z-Oberflädie or 82% of theory.

The use of the packing with the bound »ether« phase for a gas chromatographic separation

... im 'mi t "i si. S i-il.Hiien. This Γίνιιηιιΐη: is placed in a glass column with a length of 6.35 mm outside diameter and a length of time using helium as a carrier .flow rate of 50 cm '/ min and a sensitivity of the Flammeniotiisationsdeiector at the range end value of 1 - 10 "A carried out with a commercially available gas chromatograph. 0.2 µl of the sample mixture will be

injected at an initial temperature of 100 "C, and the temperature of the layer becomes continuous increased by 1.33 C / min. The versatility of this column allows the separation of both low boiling points Compounds (hexane) than me of very high-boiling compounds (phthalic acid-di-n-buiylesiei). The "Aushliiien" This column Miii of the bound »AihciK-Phasc at high emperaluren is minimal, what emerges from the slight increase in the (iniiulline of the Chiiimalogiamnis on approaching J (MVC with this mil one ', a / igen pillar arbeilenden, iiiikompcnsiericii system results.

The unusual selection of the formerly bound polymeric »ÄlherM-l'ackimg for gaseliromaiographisclie« enmmgen is evident. ¹ I erlauieii. The upper curve / the l'renniing of an (ionic from aliphaii see hydrocarbons and 4IJioiubiphenyl in a column with 1.1% to a! 'Rager /, bound "ether" at a working temperature of 275 "C. The lower curve refers to the Chromatography of the same mixture under the same conditions on a column with 1% of an aliphatic polyether but at a temperature of 200 ° C. The separation factors for these compounds in the column operating at 275 "C with the bound" ether "phase are in comparison ?. to those of aliphatic polyether at 200 ⁰ C very high A similar diagram of the aromatic compound 4-Brombiphcnyl visible, and their retention time on the "ether" column at 275 ⁰ C, 4 min while the Reientionszeit of aliphatic! Polyether at the same temperature is only 0.25 min.

Example

Making a bound

»// - Cyanäihy!« - / »Carrier Z« phase for caschromatography

In a 100 ml round bottom flask, 25 ml of the purest dioxane is added. 2 ml of 0.1 normal hydrochloric acid and 5.0 ml of a solution of p'-Cyanäthyltriäthoxysilan in dioxane charged at a concentration of 70 mg / ml. The mixture is 1 hr., And then heated at reflux in a flat Hindampfsehale / \\ 25 g mil acid> s treated carrier Z μιη added with grain sizes from 125 to 149. The solvent is driven off while stirring the mixture under the flow of a hot air blower. The mixture is then heated to 150.degree. C. in a forced-air oven for 1 hour. The material is then extracted three times with refluxing with 300 ml of absolute methanol each time, as described in the previous examples. The Klemenlar analysis of the end product gives 0.205 and 0.205% carbon, 0.025 and 0.020% hydrogen and 0.076 and 0.071% nitrogen, which is 0.72%. polymerizate on the surface of the support Z or 86% of theory.

The very high temperature resistance of the pack with the bound »/! / - cyanoethyl phase is shown in FIG. 10. This figure shows the background current strength of a flame ionization detector. which is operated with an end-of-range value of I · ΙΟ- ¹ * A if a glass column of 6.35 mm outer diameter and 3.8 mm clear width with the bound »/ i-cyanoethyl« phase with a programming of 100 to 300 ° C is operated. The same diagram shows the background current obtained under the same conditions (shifted slightly up the scale to show the differences) with a similar column in which 1% of a methyl silicone polymer containing 25% cyanoethyl groups is mechanically supported on a carrier Z. Grain sizes from 125 to 149 μ are distributed. Before the start of the experiment, both columns are conditioned at 250 ° C. for ^{1 hour.} While the bound "nitrile" packing shows essentially no "bleeding" at 275 "C, the conventional column already begins to show a considerable background current at around 225 ° C. The" nitrile "column is stable up to at least 300" C the well-known pack cannot be used up to this temperature because of the high degree of "bleeding".

The thermal stability of the stationary phase made of chemically bound "nitrile" is also derived from the thermogravimetric curve of FIG. II. These values are measured using a thermogravimetric analyzer räl obtained, which with a heating speed of IO "(7min and a slow speed of 85 cmVmin is operated. The curve shows the weight loss of a 100 mg sample of the "Nitri!" Material as a function of temperature. This investigation shows that the organic polymer phase up to is essentially stable at about 325 ° C and then slowly decomposes at higher temperatures begins. 51)

The extent of the column "bleeding" at 300 ° C is compared in Table III for the substances with the bound "ether wound" nitrile "phases with conventional, mechanically retained liquid phases. For all measurements, carrier Z is used as a carrier, and all the columns are conditioned prior to measurement of 16 hrs. At 25O ⁰ C, with the exception of the column with aliphatic! Polyether. which is conditioned at 200 ° C. The selectivity of the packing with the bound "ether" phase can roughly be compared with that of the aliphatic polyether. The values in Table III show the high heat resistance of aliphatic polyether and the bonded "ether" phase on carrier Z. A similar comparison is made between the bonded "nitrile material" and the methyl silicone polymer, a polymer containing 25% nitrile groups. The better thermal stability of the bound polymer is evident. How derTabelle results from the value of the last line III, is at lower Polymerisatkonzentrationen even to a lower column "bleed" instead

Table 111

"Bleeding rates of gas chromatographic columns

Carrier: "Carrier Z" with grain sizes from 105 to 149 μm

'l'hnse

Ik'ludiing. »Ausblutungsu-gcsehwin- Weight- "/" digkciibei J00-'C (A at Bercichsendwcrl) 1.0 5 χ 10- '» 1.1 7 χ IO "' 1.0 2 χ OK " 0.72 I χ IO - "' 0.12 1 χ 10 "

¹¹¹ aliphatic polyethers

bound "ether" phase methyl silicone polymer bound "nitrile" phase bound "nitrile" phase

The stationary phase of chemically bound »nitrile« shows, in comparison to the similar but conventional stationary phase in gas chromatography, very high specific retentions for polar compounds: the elution temperatures for polar compounds which are attached to a pack with a bound »Ni ^; - tr:! «phase through. Gas chromatographs with programmed temperature chromatographies are high.

;;. 2o This characteristic is a function of the high polarity of the polymeric phase and can lead to

': jj It may be advantageous to carry out certain selective separations. F i g. 12 shows the decomposition of mixtures from

tj ^; aromatic hydrocarbons in a column that contains only 0.12% bound nitrile phase on carrier Z.

After injecting the sample, the column is held at 25 ° C for 1 minute and then for a temperature rise 3j programmed at 15 ° C / min to 100 "C.

ψ 25 The stability of the packings with the bound phase at high temperatures enables chromatographic

q Separations within wide temperature ranges without changing the column. at

i! Using the invention it is possible to produce chromatographic phases of a high degree of polarity.

[ι; which have a resistance wedge at high temperatures, which so far only have non-polar stationary phases

A silicone compound (such as polydimethylsilo, polyhydric silicate, etc.) could be obtained.

Λ in

■ ^ B e i s ρ i e I b

i; Bound ion exchange phase for the hot water

«I chromatography

50 ml of a 10 percent by weight aqueous solution of γ-aminupropyltriethoxysilane are left to stand for 2 hours at room temperature and then placed in a white-necked vessel together with 25 g of carrier Z with grain sizes below 37 μm. Then the solution is adjusted to pH 6 with dilute F. acetic acid. The space above the solution is evacuated several times with the water jet pump in order to thoroughly degas the carrier and to allow the carrier surface to be completely moistened by the solution. The mixture is transferred to a glass frit filter and the excess solution is filtered off. The moist filter cake is ert in an evaporating dish for 1 hour in a convection oven at 125 ° ^C. TZT. The sample obtained in this way is refluxed three times with 200 ml of fresh absolute methanol each time, the solvent being decanted after each treatment. The extracted pearls are filtered off on a glass frit suction filter, air-dried and then heated to 125 ° C. in a convection oven for 30 minutes.

This weak anion exchange can be used to create a wide variety of acidic compounds or to separate other substances from each other on this basic chromatographic medium be held back. The amino functionality can also be increased with the help of known organic reactions quaternized a strongly basic tetraalkylammonium derivative. The equatorial form acts as strong anion exchanger.

Example 7

Bound phase for capillary gas chromatography

A 100 m long and 0.25 mm wide glass capillary is made by passing concentrated nitric acid through it cleaned while heating over a steam bath. Then the capillary is thoroughly using Washed out distilled water to remove all acid, rinsed with the purest acetone and washed with dried with dry nitrogen. Then 50 ml of a 5 percent by weight solution are poured through the capillary

bti of Amyltriäthoxysilan and then connected dry nitrogen to the capillary and the excess Blow out the solution under nitrogen pressure. The flow of dry nitrogen through the capillary is stopped continued until all excess solvent has evaporated. whereupon a thin one! 'him of Amyliriätho \ ysilan remains on the inner surface of the glass capillary. Then you pass a stream of luminous air (relative I Viieliligkcit SW ") through the capillary":, until the silane ester is completely hydrolyzed. what can be seen in it / ti,

r .. d: iU sich, uus doi capillary wedge! Ath.iiinl inch '"enlwic! ·. .Ll. I lieraul becomes du- capillary into an I H) (licil.fen (> fen and a stream of dry sugar is drawn slowly through the capillary for several hours.

This column with the phase bound to the capillary is particularly suitable / for dismantling complicated composite mixtures of aliphatic and substituted aromatic hydrocarbons.

Examples 8 to 12

Table I V lists a number of chromatographic packings with bound phase which .I can be prepared using the methods described and from the Kcugcn / icii described. Further The table lists the applications / weekc of the various chroniaiographical packs.

! ahelle IV carrier reagent Poly con use ie- densat. the pack picl CJcw .-% Diatonia earthc. Phcnyltriethoxysilan 5.0 I low temperature gas 8th 74-149 µm Ehroniaiographie Silica gel. //-(3.4-Epoxycyclo- 10.0 Liquid s-adsorp 9 37-44 μm hcxyl) -athyli> \ ysilane tion distribution chromatography "Textured" 3-chloropropyl 0.75 nutty distribution IO Giäiprflcn, tt HIHtMWA γ JII (IIl ! l! ng ">«. "hrr> ni: iiographie 44-o3 μ in »Carrier Ζ« L- (+) -p- [5-i-methoxycarbonyl] - '. () liquid chromato- Il 5-aniinopent-1 -yl-sulfamoyl] - graphic separation phenyl trimethoxysilane of optically active Isomers Silica gel. / -Glycidoxypropyl- 10.0 Liquid distribution 12th 5-Ι0μηι trimethoxysilane lung thin-film chromatography In addition 6 sheets of drawings

Claims (1)

Patent claims: 1. Chromatographic packing comprising a substrate containing a polyvalent metal and a stationary phase, characterized in that the stationary phase consists of a polycondensate with repeating units of the general formula -Si-R ίο I 15 (R = monovalent aliphatic or aromatic hydrocarbon radical with 1 to 13 carbon atoms, which is optionally substituted by mercapto, epoxy, amino, ester, amino, alkoxy, alkoxycarbonyl. Nitro, hydroxy, sulfinyl, fluorine, sulfamoyl, sulfonyl, cyano and / or chlorine radicals is substituted; A = - O - or R)
consists, and the substrate consists of a silicon or aluminum-containing material, further that the 30 static phase chemically to the surface of the substrate through a M - O - Si bond 25th is bound (M = Si or Al,
- Si = Part of one of the recurring units of the stationary phase), and that the stationary phase is a has an average thickness of about 30 to 10000 Å and the polycondensate 5 to 80% of the volume of the stationary phase. ; 5 2. Chromatographic i-'ackung according to claim 1, characterized in that the stationary phase consists of I consists of at least two copolycondensed parts. 'S 3. Special design of the chromatographic packing according to claim 2, characterized in that κ that A in the first of the parts has the meaning - O - and that A in the second of the parts has one A monovalent aliphatic or aromatic hydrocarbon radical with 1 to 13 carbon atoms is g 40 tet, which is optionally replaced by mercapto-, epoxy-, amino-, Fstcr-. substituted amino. Alkoxy, alkoxycar §. bonyl, nitro, hydroxy, sulfinyl. Fluoro, sulfamoyl. Sulfonyl. Cyan and / or Chlorresic is substituted. i / i 4. Chromalographischc pack according to claim!, characterized in that the substrate made of Kicsel- It consists of acidic or natural particles. Si 5. Chromalographic packing according to claim I. characterized in that the stationary phase is a Si r. has an average thickness of about 50 to 2000 Λ. ir 6. Chromatographic packing according to claim I. characterized in that the poly condensate 25 to , ά 65% of the volume of the stationary phase. ft 7. A process for the production of Ehromalographisehen packs according to claim I. by treatment £] the surface of the silicon-oiler aluininiumhalligen substrate with a solution of a silanol of the general jr-i 'such a formula I ho r; Ii Si HO R ₄ * i (R4 = monovalent aliphatic or aromatic hydrocarbon radical, which may be replaced by mercapto, Epoxy, amino, ester, substituted amino, alkoxy, alkoxycarbonyl, nitro, hydroxy, sulfinyl, bo fluorine, sulfamoyl, sulfonyl, cyano and / or chlorine residues is substituted: R ₁ '= hydroxyl or R4) and polycondensing the silanol by heating the solution, characterized in that an im essential non-aqueous acidic or basic solution used.die less water than about lOOfachc contains animal equivalents of polycondensable silanol and this solution before treatment of the substrate partially pre-polycondensed by heating. ι, · S. The method according to claim 7, characterized in that the solution of the polycondensation resin During the first heat treatment, the silanols are heated to a temperature less than KM) C '. ^L ). Abiiiulcniii) 'ilcs method according to claim 7 or H, il.nliiivh characterized, that the Iosiiny of the polycondensable silanol before the initial heat treatment with the surface of the silicon <«ki aluminum-containing substrate brings into contact. 10. The method according to claim 7 to 9, characterized in that d; ili one before the / wide heat treatment most of the solvent removed from the solution. ! 1. The method according to claim 10, characterized in that the non-aqueous solvent is ether or tetrahydrofuran is used. 12. Use of chrumatographic packings according to claims 1 to b in cliromatographic separation devices for performing chromatographic separation processes.