CA1139588A

CA1139588A - Ceramic body for chromatography and process for preparation thereof

Info

Publication number: CA1139588A
Application number: CA000332574A
Authority: CA
Inventors: Koichi Nagata
Original assignee: Kyoto Ceramic Co Ltd
Current assignee: Kyoto Ceramic Co Ltd
Priority date: 1978-07-27
Filing date: 1979-07-26
Publication date: 1983-01-18
Also published as: IT7924719A0; GB2029813A; FR2435448A1; IT1123488B; NL7905805A; GB2029813B; FR2435448B1; DE2930585A1

Abstract

Abstract of the Disclosure Disclosed a ceramic body for chromatography, which consists of a calcined molded body of alumina particles composed mainly of .alpha.-alumina, preferably containing a minor amount of .gamma.-alumina, and which has a narrow pore size distribution range.
This ceramic body has no substantial adsorbing property and therefore, when it is used for use like to thin layer chromatography or gas chromatography, the tailing phenomenon is not caused to occur at all and a high separating capacity can be obtained stably.

Description

~3"-3~
This invention relates to chromatographic process and to a ceramic body for chromatography consisting of a calcined molded body of ~-alumina particles. More partic-ularly, the invention relates to a ceramic body which exerts a high and stable separating capacity without substantial occurrence of the tailing phenomenon when it is used for use like to thin layer chromatography or gas chromatography.
Chromatography is broadly used in the fields of bio-chemistry, manufacture of agricultural chemicals, manu-facture of medicines and other various chemical industries as a process in which a sample is separated to the respective components by utilizing adsorption and/or distribution.
The chromatography heretofore adopted in these fields is roughly divided into two types, that is, the adsorption type and distribution type. Thin layer chromat-ography is a typical instance of the chromatography utilizing the principles of both the adsorption type and distribution type, and a typical instance of the chromat-ography utilizing the principle of the distribution type is liquid chromatography. In the thin layer chromatography, a mixture formed by kneading an inorganic or organic adsorbent such as silica gel, alumina or polyamide with a binder, water and other appropriate components with the use of a mixing solvent is coated in the form of a thin layer on a plate-like support such as a glass sheet, a syn-thetic resin sheet or a metal sheet, the coated mixture is dried under predetermined conditions, an unknown sample is dropped on one end of the thin layer, the lower end or upper end of the plate-like support is dipped in the solvent while the solvent is being evaporated, and after a certain

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" .

developing time a adsorption and separation of the sample are repeated while -the solven-t is passed -through -the -thin layer by the capillary phenomenon, By utilizing this pheno menon of the repeated adsorption and separation of the sample, the unknown sample is separated and analyzed, In -the thin layer chromatogra.phy, an expensive equipment for formation of a thin layer9 such as an ; applicator, must be used and a considerable skill is necessary f`or forming a -thin layer by using such equipment, Fur-thermore 9 a thin layer having a uniform thickness ¢an hardly be obtained. If the -thickness of the thin layer is not uniformg attainmen-t of uniform development is very difflcult and -the result of development lacks reliability and reproducibility. Moreover, even if thin layers are composed of the same material, the activity differs depending on the degree o~ drying of the adsorbent. Still further~
: it is very difficult to preparc a number of thin layers continuously, and since a thin layer is formed on a glass substrate or t'ne like by coating9 the thin layer is readily peeled by vibra-tion or the like during transportation-, Thus, the conven-tional technique o~ thin layer chromatography ~ includes various defects, ; The liquid chromatography where a substance having a : large distribution coefficient is separated and eluted out preferen-tially is a typical inst~nce of the distribution type chromatography, More specifically, it is necessary to inject a m:inute amount of a liqui.d sample into a carrier liquid before a column against the pressure of the carrier liquid ( for example, 300 a-tmospheres ) promptly and precisely, In the conven-tional piercing cap technique using a piston -typc injec-tion mechanism ~or t;he injection, since the inner pressllre of the carrier liquid is high, the reproducibility is not alway; good. Moreover, different materials should be chosen and used for piercing caps according to the in-tended ob,lec-t of chromatography.
Furthermore 9 when a ~ine tube of the injection device is introduced into the carrier liquid 7 a shock pressure is generated because of the non-compressibility o~ -the carrier liquid and this shock pressure is transmitted to the colurr~
and detec-tor, and the analysis process is susceptively influenced. In such liquid chromatography 9 the amount to be developed at one time is small and if -the sample is not diluted 9 the separation capacity is degraded.
Therefore~ the liquid-phase chromatography is defec-tive in that it -takes a long time to separate and collect -the sample in an amount necessary for analysis or -the like. Furthermore, it is difficult -to pack the sta-tionary layer uniformly in a column and commercially available products are very expensive. Moreover9 the liquid chromatography is disad-vantageous in that detection must be conducted on separationand collection by such means as ultraviolet analysis or refractive index analysis and -the entire equipr.lent system becomes voluminous 9 and that the equipment system must be washed sufficiently before and after separation and collection As will be apparent from the foregoing illustration, the conven-tional chromatography of either the adsorp-tion ; type or the distribution type involves various defects wi-th respect to -the separation capacity and -the operation procedures.

In gas chromatography, a gaseous sample or gasified liquid or solid sample is passed through a tube uniformly packed with a filler and thus developed by means of a carrier gas and the sample is separated into respective components. This gas chromatography is roughly divided into gas-solid chromatography where a solid power having an adsorbing capacity is used as the filler and the respective components are separated by utilizing the difference of the adsorbing property and gas-liquid chrom-atography where a lowly volatile liquid or a solid to be liquefied at the application temperature is used as the filler and the respective components are separated by utilizing the difference of the solubility.
Celite or the like having no adsorbing activity is ordinarily used as a carrier of the stationary phase in the above-mentioned gas-liquid chromatography, and conventional alumina cannot be used for this purpose because the adsorbing activity is very high and tailing is readily caused.
According to this invention, there is provided in a chromatographic process a ceramic body, which has chemical structure and characteristics quite different from alumina here-tofore used, as the adsorbing medium or stationary phase.
More specifically, in accordance with this invention, there is provided a chromatographic process wherein components in a liquid or gaseous mixture are separated by passing the mixture over a solid stationary phase, characterized in that said solid stationary phase is in the form of a thin molded and calcined porous sheet of alumina particles composed mainly of ~-alumina, in which sheet the pore size distribution range is from 0.1 to 10 microns, or in the form of particles obtained by pulverizing such a molded and calcined porous sheet.

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Preferably, the alumina particles have a particle siz~
not exceeding 30 microns.
Since the ceramic body for chromatography according to this invention has no substantial adsorbing property, - 5a 513~

the tailing phenomenon is no-t substan-tially caused when ma-terials are separa-ted 7 and the high separation capaci-ty can be attained very s-tably.
Still fur-ther~ -this ceramic body for chromatography can be provided very easily at a low cost only by molding and calcining alumina particles composed mainly of a-alumina, Furthermore, the ceramic body for chromatography according -to this invention is very excellent in the mechanical strength, the easiness in handling and the adaptability : 10 to -the analysis opera-tion.
This invention will now be described in de-tail by reference -to the accompanying draw:ings, in which:
Fig, 1 is a diagram illustrating the state where sugars are separated by using a sheet-like ceramic body for chroma-tography according to this invention, Figs t 2 and 3 are diagrams illustrating the state where amino acids are separa-ted by using a shee-t-like ceramic body for chroma-tography according to this invention9 ~ ig, L~ is a diagram illustra-ting the state where oil soluble dyes are separated by using a shee-t-like ceramic body for chromatography according to this invention, Fig, 5 is a diagram illustrating the s-tate where polystyrenes having various molecular weights are separated by using a sheet like ceramic body for chromatography accord-ing to this invention, Fig, 6 is a graph illustrating a relation between thedeveloping distance and the molecular weight in the chroma-togram o~ Fig, 59 Figs, 7 and 8 are diagrams illustrating results o~
separation of samples by using a stationary phase c~rrier -- 6 _ for gas chromatography according -to this invention.
In this lnven-tion, crys-ta]line alumina particles com-posed mainly of ~ 23 are ~,lsed as the s-tarting ma-terial.
Of course 9 alurnina par-ticles composed solely of a~h~203 may be used9 but when alumina particles comprising more than 50 % by weight9 preferably 60 to 80 % by weight9 of ~-A~20 and less than 50 % by weigh-t 7 preferably 20 -to 40 S~ by weight9 of r-alumina are used9 an optimurn separa-tion capaci-ty can be obtained.
Alumina particles having an average par-ticle size smaller -than 30 ll and a narrow particle size distribu-tion range are preferred, Optimum resul-ts can be ob-tained when alumina particles having a particle size distribution range of from 1 -to 10 ~ are employed.
The ceramic body of -this invention can be prepared according to a process comprising molding a composition ; comprising crystalline alumina particles composed mainly of a-~lumina9 a resinous binder and a solven-t into the form of a shee-t 9 calcining the molded shee-t a-t a -temperature ~ 20 of 85Q to 1600C. and9 if necessary~ pulverizing -the cal~
; clned sheet into particles.
An acrylic resin or polyvinyl butyral ( PVB ) is prefer~bly used as the resinous binder. Furthermore9 polyvinyl acetate 9 polyesters and o-ther resinous binders may be used in this inven-tion. Aroma-tic solvents such as toluene and xylene9 alcohols such as methanol and ethanol9 ketones such as acetone and methyleth~Jl ke-tone and the like can optionally be used as the solvent, The amount used of the resinous binder is selected so that the ob-tained sheet is good for the mechanical processing9 and the amo~t used o~ the solven-t is selected so -tha-t the surfaces of alumina particles are suffiGiently we-t-ted and a flowability necessary for molding is obtained.
The above-mentioned composi-tion is made homogeneous by agitation, kneading or -the like 9 and the homogeneous composition is molded into a predetermined shape, ordinarily a planar shape 9 for example 9 a tape or sheet 9 by tape casting using a doc-tor blade, The molded sheet is calcined at a temperature of 850 to 1600C " w11ereby particles o~ ~-A~203 are partially fused to one another and integrated wi-th one another to ob-tain a microporous molded body. A preferred calcination temperature differs to some extent depending on the kind of chromatography, For exarnple~ in case of liquid chromatography 7 a calcination -temperature of 1250 to 1400C, is preferred and in case of -the s-ta-tionary phase carrier for gas chromatography, a calci-nation tempera-ture of 1150 to 1400C.
is preferred.
This calcined sheet has a narrow pore size distribution range 9 and it is preferred tha-t -the pore size dis-tribution range oe substantially from 0,1 to 10 ~, The obtained calcined and molded sheet is uscd as a ceramic body for liquid chromatography as i-t is or after it has been cut in a prede-termined size according to need.
This calcined and molded sheet is used as a stationary phase carr:ier for gas chromatography after it has been pulverized into particles ~nd if necessary, the particle size has been adjusted.
This invention will now be described in detail by reference to the following Examples that by no means limit -the scope of -the invention.
Example 1 S-tarting a-Ae20~ partic]es having -the average particle si~e of 1 to 2 ~ were used. Then 9 100 parts by weight o~
the s-tar-ting material was mixed wi-th 8 parts by weight, as the solids 9 of an acrylic resin and 40 parts by weigh-t of -toluene as -the solvent, The resul-ting composition was kneaded and molded in-to a tape having a thickness of 1 mm by using a doctor blade, Plates having a size o~ 1,5 cm x 10 cm were cu-t from the so molded -tape ancl calcined at 850 9 1285, 1390 or 1600C " and -the rela-tion between -the calcina-tion -tempe-rature and the developing speed was exarnined. Resul-ts obtained when n-hexane was used as a developing liquid are shown in Table 1, Table 1 Run No. ~ iO~ æ___ ure _( ~ Developin~

1 8~0 16

3 1390 30

4 1600 42 :
Note The developing distance of the solvent was 6,0 cm in each run, The ceramic body obtained by carrying ou-t calcination at 850C. showed a shortest developing time~ i,e., 16 minut~s 9 among the so-obtained calcined ceramic bodies, but from the viewpoint o~ the strength of the ceramic body for chromatography, the ceramic body obtained by carrying ou-t calcination a-t 1285C, was most preferred. Accordingly, the ceramic body formed by carrying out calcination at 1285C. was cut into s-trips and subjected to the experimen-ts described in Exarnples 2 and 3 given below.
~ ~ S~ s) D(~)-lactose, D(~ sucrose and L(-)-sorbose and a mixture thereof were developed with a mixture of water/
ethyl acetate/n~propanol (1135/10 in Volume/Volume ra-tio) by using -the shee-t~like ceramic body of Example 1 Colora-tion was performed by using sulfuric acid. Results obtainedwere shown in Figure 1 In Fig. 1, (a), (b), (c) and (mix) stand for D(~ lactose, D(l)-sucrose, L(-)-sorbose and mixture thereof respectively ~ le 3 ~ ~
Results where glycine, D9L--alanine9 D,L-valine and L-leucine were developed by using the sheet like ceramic body of Example 1 were shown in Fig 2. A mix-ture of water/

;
~ e-thyl acetate/rl~propanol (5/35/10 in volume/volume ratio) ;
was used as developer, and ninhydrin was used for coloration ~`~ In Fig 2 and ~ig. 3 as mentioned below9 (i), (ii)9 (iii) - ~ ~ and (iv) s-tand for glycine9 D9L-alanine9 D,L-valine and L-10ucine respectively ~s will be apparent from the foregoing illustration, in this invention9 since ~:-A~203 which is ~ery stable and has no substantial adsorbing property is used as the ceramic body for chromatography, substances can be cl~arly separated based on the difference of the distribution coefficient.
Characteristic properties of the ceramic body for ~0 chrom~tography according to this invention are as follows .
.

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(1) Since a~AB203 has a very low ac,-tivi-ty and is very s-table, ~the cera!nic body exer-ts no substantial adsorbing property9 and che ceramic body can be applied to systems to which only liquid-phase chromatography has heretofore been applied.
(2) Large quanti-ties of samples can be separated in a short time very simply, (3) Since alumina uniform in the particle size is molded by using a binder in the ceramic body of this in~ention9 a uniform thickness can be obtained and the resulting ceramic body is excellent in the separa-ting capaci-ty and reproducibility.
(4) Since calcina-tion is carried out after molding, the mechanical strength is high and deformation is no-t caused in the ceramic body of this invention.

(5) Desorption can easily be accomplished only by cutting off -the portion used for separation and treating - it with a solven-t capable of dissol~ing the separated component suf~iciently.
; 20 (6) Since molding can be performed continuously 7 the manufacturing cos-t can be remarkably reduced, Example_4 A sheet-like ceramic body was prepared in the same marmer as described in Example 1 except that a-A~203 and Y-A~203 were used in combination at a weight ratio of 75/
25 instead of the a~A~203 used in Example 1 and calcina--tion was c~rried out at 1350C, Amino acids were separated in the same manner as des-cribed in Example 3 by using the so prepared sheet-like ceramic body, Obtained results are shown in Fig, 3~ from which i-t ~`till readily be unclerstood -tha-t even in case o~
subs-tances ha-ving a rela-tively low R~ value D~L-valine, L-leucine, occurrence of the tailing phenomenon could be completely inhibited and each spot was very clear, ~ ~ ~
A mix-ture of Indophenol Blue (I), Sudan Red (II) and 4-Dimethylaminoazobenzene tIII~ as devcloped with n-hexane by using the ceramic body of Example 4, The results obtained were shown in Fig, 4, from which it will be understood that each spot was very clear and occurrence o~ the -tailing phenomenon could be completely inhibited, ~esults where ~ kinds of polystyrene having an average molecular weigh-t (M~) of 2,000, 20 9 000 ~ 160 9 000 and 1~800,000 respectively were developed with tetrahydro~uran (THF) and e-thanol (15~11 in volume ra-tio) by using -the sheet like ceramic substance were shown in Fig, 5, Iode was used for coloration, The relation be-tween -the molecular weight of polys-tyrene and the developing distance were shown in Fig, 6 from which it will be unders-tood that there is established a linear relatlon between the developi.ng ~ distance and the molecular weigh-t and that the molecular ; weight o~ polymer can be estimated from this relation, Ex ~ 7 High-purity alumlna (A~203) was molten in an electric furnace and was then solidified, The resulting mass was ; pulverized and classified -to obtain a white corundum crystalline powder having a particle size distribution range of ~rom 0,5 -to 80 ~1 and an average particle size of 10 ~1 ( 30 1 ~ ), Then, 100 parts by weight of the so ?~3 formed crys-talline powder was mixed with 20 to 60 par-ts by weight ( preferably 30 to 50 parts by weight ) of toluene as the organic solven-t~ and ~,he mixture was sufficiently stirred i~, a po-t mill. Then5 the mixture w.~s mixed with 4 to 40 parts by weight ( preferably 6 to 15 parts by weigh-t ) of an acrylic resin as the binder, and -the mix~
ture was sufficiently stirrecL. Then 9 the mixture was molded into a green ceramic tape having a uniform -thick-ness of 0.2 to 2,0 mm ( preferably 0.25 -to 1~0 mm ) accord-ing to the doctor blade method. The green tape was cut into a prede-termined size and calcined at 1000 -to 1600C, ( preferably 1200 to 1350C. ) to obtain a sheet-like ceramic hody having a pore size of 0,1 -to lO ~, The sheet-like ceramic body was pulverized in a mortar and a fraction ; 15 of 60 to 80 mesh was collec-ted, Then, 22 g of -the so ; obtained powder was dipped in a solution of 0.7 g of a silicone rubber in 15 cc of tetrahydrofuran ( hereinafter referred to as ~' THF li ). TEIF was evaporated while the mixture was quietly agitated hy a spatula, whereby a ; 20 stationary phase was obta,ined, The so prepared stationary phase for gas chromatography was packed in a column having a length of 2 m, and experiments descrlbed in Examples ~ and 9 were carried out by using the so prepared packed column.
~ _8 A mixture containing henzene, -toluene and o xylene a-t a volume ra-tio of 1/l/1 was separated under the following condi-tionsu ; ~low rateO 29.2 m~/min Amount injectedO 3 3~J~

Column pressure~ 0,8 ~g/cm2 'I'emperature 130C, Carrier cgaso nitrogen (l~T2) gas Stationary phase liqui~O silicone rubber Detection me-thod~ TCD ( thermal conductivity detector ) method Ob-tained results are shown in Fig, 8, As wi].l be apparent from the graph of Fig. 8, sharp peaks corresponding to the separa-ted substances were detected, and the presence of benzene, -toluene and o-xylene could be clearly confirmed at points ~9 B c~nd C, respectively.
Example 9 A mixture of dioxanej butyl acetate, isobutyl ke-tone, trans-decalin and cis-decalin was se.parated under the following conditions.
Flow rateo 30 me!min Amount injectedo 5 1 - Column pressureo 0,7 Kg/cm~
Tempera-tureO 130C.
Carrier gas~ ni.trogen (N2) gas ~: S-tationary phase liquido sillcone rubber De-tection~methodo '~CD method : Obtained results are shown in Fig. 8. As will be .
apparen-t ~rom the graph of Fig. 8~ sharp peaks correspond-;: . 25 ing to the respective substances were observed. More speclfically9 the presence of d10xane9 butyl acetate7 lsobutyl ketone and cis-decalin could be confirmed at polnts D9 E 7 F and G9 respectively, : It was found that if the pore size exceeds 10 ~3 ~0 separation of -the respective components becomes difficult, As will be apparen-t ~rom the.~oregoing illustration, since alumina having a uni~orm crystal par-ticle size is used for the stationary phase carri.er for gas chromatography according -to this inven-tion, the sta-tionary phase carrier has no substantial adsorbing property and hence 7 the tailing phenomenon is not caused to occur at all. More-over, since the bulk density of -the stationary phase carrier alumina of -this invention is higher -than that o~ celite customarily used ln this field 9 the time required for packing can be shortened -to about 5 minutes ( ~everal hours are necessary in case o~ conventional celite ), Moreover, since the stationary phase carrier o:~ this invention is hard and hardly pulverizable, it is not broken or divided when the column is wound in the spiral ~orm.
Furthermore, since -the s-tationary phase carrier o~ this invention is prepared by calcining a molded body hàving a tape~like shape and pulverizing the calcined body, the pore siz~ distribution range ( the range of sizes o~ pores among crystal particles ) is very narrowg that is from 0,1 to 10 ~, and there~ore, the resulting stationary phase carrier can exert an excellen-t separa-ting capacity very stably.
~ 15

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A chromatographic process wherein components in a liquid or gaseous mixture are separated by passing the mixture over a solid stationary phase, characterized in that said solid stationary phase is in the form of a thin molded and calcined porous sheet of alumina particles composed mainly of .alpha.-alumina, in which sheet the pore size distribution range is from 0.1 to 10 microns, or in the form of particles obtained by pulverizing such a molded and calcined porous sheet.

2. A process according to claim 1 wherein the alumina particles have a particle size not exceeding 30 microns.

3. A process according to claim 1 or 2 wherein the alumina particles consist of a major amount by weight of .alpha.-alumina and a minor amount by weight of .gamma.-alumina.