JP3129097B2 - Zirconium oxide particles for liquid chromatography and their preparation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to zirconium oxide for alkali-resistant liquid chromatography and a method for producing the same.
The present invention also relates to a packing material for a separation column suitable for separating biopolymer substances such as peptides and proteins by reversed-phase liquid chromatography.

[0002]

2. Description of the Related Art Silica-based carriers have been often used as column packings in liquid chromatography. However, since silica-based carriers are mainly composed of silicate glass, it is difficult to use them for separation using an alkaline mobile phase, and even if the mobile phase itself is not alkaline, separation using an alkaline washing column after use is required. Basically could not be applied to such. In this regard, the inclusion of a zirconium oxide (ZrO ₂ ) component in the above silicate glass improves the alkali resistance as a carrier (see JP-A-62-59553, JP-A-62-67450 and JP-A-62-67450). 64
-46646). Further, attempts have been made to use zirconium oxide as a carrier for liquid chromatography for applications requiring alkali resistance (J. Nawrocki et al, J. Chromatography A, 657, 229-28).
2 (1993)).

[0003]

The zirconium oxide has a characteristic of being excellent in alkali resistance, however, during the manufacturing process (especially the calcination treatment), the crystal form of the zirconium oxide gradually changes from a tetragonal system to a monoclinic system. Because of the change, it has been difficult to stably produce the distribution of pore diameter and pore volume of zirconium oxide particles, which are important characteristic values when used for liquid chromatography, under predetermined conditions.

[0004]

As a result of studying this problem, it has been found that by adding a silicate compound when hydrolyzing an aqueous solution of a zirconium salt, a conventional zirconium oxide is used in the firing step of a zirconium oxide sol. That is, the present invention relates to a tetragonal zirconium oxide for liquid chromatography containing 0.1 to 10% by weight of silica and a method for producing the same. When the surface of the obtained tetragonal zirconium particles is modified with a silane-based, aluminum-based, titanium-based, or zirconium-based coupling agent, or an alcohol or a halogenated hydrocarbon, a packing material for liquid chromatography is obtained. Since the zirconium oxide of the present invention has a sharp pore diameter distribution and a stable pore volume, high separation performance can be obtained. Further, by fixing the crystal form of zirconium oxide as a tetragonal system, it is possible to increase the pore volume of zirconium oxide, thereby increasing the holding power of the sample and extending the holding time, thereby improving the separation. There is. Hereinafter, the method for producing tetragonal zirconium oxide will be described in detail.

An alkali silicate such as sodium silicate or potassium silicate or an alkoxysilane such as tetramethoxysilane or tetraethoxysilane is added to alkaline water such as sodium hydroxide, potassium hydroxide or ammonia, and zirconium is added thereto. An aqueous solution of a salt (concentration of 0.5 to ₂ mol / l as ZrO ₂ ) is added dropwise to completely hydrolyze the solution, and this aqueous solution is heat-treated under alkaline conditions under reflux or under pressure. Alkali silicate or alkoxysilane as a silica source may be dropped simultaneously with dropping of the zirconium salt. In the heat treatment process, a weakly acidic to neutral zirconium oxide aqueous solution shows a remarkable thickening phenomenon, and therefore it is necessary to add a zirconium salt aqueous solution to alkaline water sufficient to maintain the aqueous solution even after the completion of hydrolysis. The heat treatment time under reflux or pressure affects various characteristic values of zirconium oxide, and is preferably 8 to 500 hours. More preferably, 10 to 500 hours are desirable. If the heat treatment time is short, the cohesion of the primary particles is weakened because the colloid formation is incomplete. Therefore, at least heat treatment
Unless performed for 8 hours, it is not suitable as a packing material for liquid chromatography. The obtained zirconium oxide colloid solution is washed and then spray-dried to obtain spherical zirconium oxide, and the bulk zirconium oxide may be mechanically crushed. Next, the granular zirconium oxide is fired. Since the mechanical strength of the particles becomes extremely weak when firing at 1100 ° C or more, the firing temperature is desirably 200 to 1000 ° C. The average particle size, pore diameter and pore volume of zirconium oxide are controlled by the following method.

[Control of Average Particle Size] In spray drying, washed zirconium oxide is again mixed with water to form a slurry, and the slurry concentration at this time affects spheroidization or average particle size by spray drying. . In general, the lower the slurry concentration, the smaller the particle size. However, when the slurry concentration is 3% by weight or less, the amount of irregular fine particles increases. Therefore, in order to control the average particle size of the spherical zirconium oxide to 0.5 to 300 microns, a slurry of 3 to 25% by weight is used. More preferably, a slurry concentration of 8 to 18% by weight is desirable. An atomizer that sprays only slurry in spray drying.
When using a spray dryer of the type, spherical zirconium oxide particles having a small average particle diameter can be obtained by increasing the rotation speed of the atomizer or spraying from a nozzle. In the case of a two-fluid system (double tube) The particle diameter can be controlled by the nozzle diameter.

[Control of Pore Diameter] The baking treatment after spray drying affects the pore diameter of zirconium oxide. The pore diameter has a maximum value at a firing temperature of 600 to 800 ° C., and is about 300 Å. Here, the distribution of the pore diameter was measured using a mercury intrusion pore distribution measuring device. Pore diameter at 10% mercury intrusion as an index of pore size distribution (V10)
Is divided by the pore diameter (V90) at a mercury intrusion of 90% (V90 / V90) (smaller values indicate a sharper distribution). In the present invention, V10 / V90
Is obtained from 1.2 to 5.3. [Control of Pore Volume] The pore volume increases as the reflux or pressurization heat treatment time increases. FIG. 1 shows the pore volume when zirconium oxide prepared by changing the reflux time was calcined at 600 ° C. for 2 hours. In the present invention, the pore volume is 0.17 to 0.42.
ml / g, 600-800 ℃ as well as pore diameter
At the firing temperature of.

The obtained zirconium oxide particles have an inner diameter of 6 mm.
The column was packed in a φ, 150 mm length column, and an alkali resistance durability test was performed using 1N-NaOH as a mobile phase. 1N-NaOH 1
When the solution was passed at a rate of ml / min, no outflow of zirconium was observed until 5000 hours, indicating that zirconium oxide for liquid chromatography having sufficient alkali resistance was obtained.

The surface of the zirconium oxide thus obtained is coated with a silane such as octadecyldimethylchlorosilane, ethylchlorosilane, aminopropyltrimethoxysilane, cyanopropyldimethylchlorosilane, octadecyldimethylchlorozirconium, cyclopentadecyl-trichloro-zirconium or the like. Aluminum-based coupling agents such as zirconium-based, dimethylaluminum chloride and diisobutylaluminum chloride, or titanium-based coupling agents such as diethyl-dichloro-titanium and ethyl-trichloro-titanium; or alcohols such as n-octyl alcohol and stearyl alcohol or chlorides. Modification using at least one compound selected from the group consisting of halogenated hydrocarbons such as n-octyl and stearyl chloride It can be used as a reverse phase liquid chromatography carrier. For example, when octadecyldimethylchlorosilane (ODS) is modified, it can be applied to efficient separation and analysis of biopolymers such as peptides and proteins by using a buffer having a pH of 2 to 12 as a mobile phase.

[0010]

【Example】

Example 1 To 1 liter of a 4 mol / l aqueous sodium hydroxide solution was added 13 g of an aqueous solution of No. 3 sodium silicate, and then 1 liter of a 1 mol / l aqueous zirconium oxychloride solution was added to 1 liter /
The mixture was dropped and mixed with h to produce a zirconium oxide sol. This was put in a 2 liter flask with a reflux tube at 105 ° C for 62 hours.
Reflux for hours. This was subjected to suction filtration washing, and re-slurried to obtain a slurry concentration of 12% by weight. Using an atomizer type spray dryer, the flow rate was 1 liter / h,
Spray drying at a hot air temperature of 150 ° C. and a disk rotation speed of 15,000 RPM gave tetragonal only spherical zirconium oxide. When this is fired at 600 ° C for 2 hours, the average pore diameter is 80
Angstrom, spherical zirconium oxide having a pore volume of 0.35 ml / g was obtained. This was stirred in 1N-HCl for 1 hour to perform an acid treatment to obtain tetragonal zirconium oxide particles for normal phase liquid chromatography. The crystal system of zirconium oxide was confirmed to be a tetragonal system using an X-ray diffractometer.

Example 2 A zirconium oxide sol was produced in the same manner as in Example 1 except that 37 g of No. 3 sodium silicate was used as a raw material. The subsequent heat treatment and calcination treatment in an alkali were carried out in the same manner as in Example 1 to obtain zirconium oxide particles consisting only of tetragonal system having an average pore diameter of 298 angstroms.

Comparative Example 1 Zirconium oxide particles were produced in the same manner as in Example 1 except that sodium silicate was not added. In this case, a mixture of tetragonal and monoclinic zirconium oxide was formed. Table 1 shows the results of measuring the average pore diameter and the pore diameter distribution of the zirconium oxide particles of Examples 1 and 2 and Comparative Example 1. From Table 1, in Comparative Example 1, the distribution of the pore diameter is wider than in Examples 1 and 2. This is presumably because the crystal form of zirconium oxide is not stable during the calcination process, so that the distribution of the pore diameter, which is an important characteristic of the product, is not sharp.

[0013]

[Table 1]

Example 3 10 g of the zirconium oxide particles obtained in Example 1 was added to 300 ml.
Was stirred at 105 ° C. for 2 hours, and water molecules adsorbed on the zirconium oxide particles were dehydrated at normal pressure. Then add 12 g ODS and 2.8 g pyridine at 105 ° C
Reflux for 3 hours. Further trimethylchlorosilane (TMCS)
3 g, 3 g of hexamethyldisilazane (HMDS) and 2 g of pyridine were further added, and end-capping was performed at 105 ° C. for 3 hours. Thereafter, methanol was quickly added, and the mixture was thoroughly washed with n-hexane and methanol to remove residual ODS, TMCS, and HMDS. Next, it was dried at 80 ° C. to obtain zirconium oxide for reversed-phase liquid chromatography.

Example 4 The ODS-modified zirconium oxide particles having a particle size of 20 obtained in Example 3 were packed in a column having an inner diameter of 4 mmφ and a length of 15 cm, and the state of separation by liquid chromatography was examined. Separation was attempted with water / methanol = 30/70 as the mobile phase. The supply rate of the mobile phase was 0.45 ml / min, the column temperature was 40 ° C., uracil, methyl benzoate, toluene, and naphthalene were used as samples, and detection was performed at UV 254 nm. Next, the same measurement was performed after continuous 2,000-hour liquid passage, but no change was observed in the retention time. Further, as an alkali resistance test, dil.NaOH / methano-
When the separation state was examined under the same conditions as above using a mobile phase of pH = 30/70 and pH = 11, there was no change in the retention time after continuous 1000-hour passage, and the chromatogram obtained at this time was 2
Shown in

[0016]

According to the present invention, by adding 0.1 to 10% by weight of silica to zirconium oxide, the crystal form of zirconium oxide is prevented from changing during the calcination process, and the pore size distribution, which is an important characteristic in liquid chromatography, is sharp. Zirconium oxide particles are obtained. As a result, the separation ability of zirconium oxide, which has better alkali resistance than silica, can be improved.

[Brief description of the drawings]

FIG. 1 shows the relationship between the reflux time of zirconium oxide particles and the pore volume in the case of baking at 600 ° C. for 2 hours.

FIG. 2 shows a chromatogram of an alkali resistance test performed in Example 4.

[Explanation of symbols]

 1 uracil 2 methyl benzoate 3 toluene 4 naphthalene

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B01J 20/00-20/34 B01D 15/08 C01G 25/00 G01N 30/48

Claims (5)

(57) [Claims] 1. Tetragonal zirconium oxide particles for liquid chromatography containing 0.1 to 10% by weight of silica. Wherein an average particle size in the 0.5 to 300 microns, an average pore diameter of the porous liquid chromatographic tetragonal zirconium oxide particles according paragraph 1 claims a 20 to 300 Angstroms. 3. The square for liquid chromatography according to claim 1 or 2 , wherein the square is modified with a silane-based, aluminum-based, titanium-based, or zirconium-based coupling agent, or an alcohol or a halogenated hydrocarbon. Crystalline zirconium oxide particles. 4. A zirconium oxide sol produced by adding a zirconium salt and a silicon compound to an aqueous alkali solution is heated in an aqueous alkaline solution at 80 ° C. to 150 ° C. for at least 8 hours, granulated, and then granulated at 200 ° C. to 1000 ° C. A method for producing tetragonal zirconium oxide particles for liquid chromatography, comprising 0.1 to 10% by weight of silica, which is characterized by calcining. 5. The zirconium salt is a water-soluble zirconium salt selected from the group consisting of zirconium oxychloride, zirconium nitrate and zirconium sulfate, and the silicon compound is a compound selected from the group consisting of alkali metal silicates and alkoxysilanes. A method for producing tetragonal zirconium oxide particles for liquid chromatography according to claim 4 .