JPH05273188A - Molecular weight distribution measuring method using gel permeation chromatrograph - Google Patents

Abstract

PURPOSE:To measure materials which have been difficult to be measured on the molecular weight distribution by selecting the mobile phase of GPC. CONSTITUTION:The molecular weight distribution is measured on the following materials for GPC: homopolymer polymethacrylate using a mixed liquid of methanol and phosphoric acid buffer solution as the mobile phase, a polystyrene latex solution using tetrahydrofuran as the mobile phase, and hydroxypropyl methyl cellulose using a mixed solution of chloroform and methanol as the mobile phase respectively.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a separation / quantification method using a gel permeation chromatograph (hereinafter referred to as GPC) suitable for quality control and performance evaluation of polymer substances.

[0002]

BACKGROUND ART Polymer substances known as functional materials are applied to mechanical materials, building materials, drinking materials, etc. For example, hydroxypropylmethyl cellulose is
It is used as a material for films and coatings. Therefore,
Also for use in these applications, quality control and performance evaluation of polymer substances are important, and molecular weight distribution measurement by GPC has been attempted.

For example, since polymethacrylic acid homopolymer is a substance soluble in methanol, it is measured by GPC using methanol as a mobile phase, and polystyrene latex is a water-soluble solution. Therefore, it is measured by water-based GPC. Was going on.

[0004]

However, in the measurement of polymethacrylic acid homopolymer and polystyrene latex by the conventional method, a chromatogram having no reproducibility was obtained, and accurate molecular weight distribution measurement could not be performed.
Therefore, conventional methods have not been able to sufficiently perform quality control and performance evaluation of polymethacrylic acid homopolymer and polystyrene latex.

Other than the above, for example, polyetherketone and hydroxypropylmethylcellulose have no suitable solvent for dissolving them, and thus it is difficult to measure the molecular weight distribution by GPC.

Therefore, an object of the present invention is to make it possible to separate and quantify substances whose molecular weight distribution was difficult to measure as described above by selecting the mobile phase of GPC.

[0007]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventor has selected polymethacrylic acid homopolymer, polyether ketone, polystyrene latex, hydroxypropyl by selecting the following mobile phases. The inventors have found that the molecular weight distribution of methyl cellulose and the like can be measured, and have completed the present invention.

That is, the first aspect of the present invention is a method for measuring the molecular weight distribution of a polymethacrylic acid homopolymer by GPC, which comprises dissolving the polymethacrylic acid homopolymer in a mixed solution of methanol and a phosphate buffer, and then dissolving it. The liquid is subjected to GPC using methanol and a phosphate buffer as a mobile phase, and the molecular weight distribution of the polymethacrylic acid homopolymer is measured.

Here, it is preferable in view of the control of the apparatus that the concentration when dissolved in a mixed solution of methanol and a phosphate buffer is 0.2 to 0.4 wt%. The mixing ratio of methanol and phosphate buffer is preferably 3/2 to 2/3 from the viewpoint of solubility of polymethacrylic acid homopolymer.

The pH of the phosphate buffer is not particularly limited, but from the viewpoint of preventing column deterioration, the pH is preferably 9 to 10, and the concentration is preferably 50 to 100 mM. The methanol or phosphate buffer solution itself may be a commercially available one or may be purified and used.

To dissolve the polymethacrylic acid homopolymer in a mixed solution of methanol and a phosphate buffer, for example,
The polymethacrylic acid homopolymer may be placed in a beaker and an appropriate amount of a mixed solution of methanol and a phosphate buffer solution may be added thereto, but the method is not limited. When the solution of the polymethacrylic acid homopolymer is prepared, it is subjected to GPC. A known sample introduction device can be used for applying to the GPC, whereby a predetermined amount of the solution can be injected into the GPC.
The solution injected into the GPC is applied to a separation column using a mixed solution of methanol and phosphate buffer as a mobile phase. Here, it is preferable for the operation of the apparatus that the mobile phase of GPC and the solution for dissolution are the same.

As the separation column used in GPC, a column packed with a general-purpose polymer gel can be used. For example, a packed column of vinyl alcohol copolymer can be mentioned as a suitable example.

As the GPC detecting means, for example, a differential refractive index detector is preferably used.

The second aspect of the present invention is a method for measuring the molecular weight distribution of polyetherketone by GPC, wherein the polyetherketone is heated and dissolved in dichloroacetic acid and then diluted with chloroform, and the diluted solution is diluted with dichloroacetic acid and chloroform. The mixed solution of is subjected to GPC using as a mobile phase to measure the molecular weight distribution of polyetherketone.

Here, the concentration when the polyether ketone is heated and dissolved in dichloroacetic acid is 0.1 to 0.2 wt%.
Is appropriate. The solution is diluted with chloroform, but the dilution ratio is preferably about 10 times.

The diluting solution is applied to a separation column using a mixed solution of dichloroacetic acid and chloroform as a mobile phase. Here, since the mobile phase of GPC and the diluting solution are preferably the same from the viewpoint of the operation of the apparatus, it is appropriate to use a mixture ratio of dichloroacetic acid and chloroform of 1/9.

As the separation column used in GPC, a column packed with a general-purpose polymer gel can be used. For example, a column packed with a styrene-divinylbenzene copolymer can be mentioned as a suitable example. For example, an ultraviolet absorption detector is used.

The third aspect of the present invention is a method for measuring the molecular weight distribution of polystyrene latex by GPC, in which the polystyrene latex solution is subjected to GPC using tetrahydrofuran as a mobile phase to measure the molecular weight distribution of polystyrene latex. It is characterized by

The concentration of tetrahydrofuran is not particularly limited, and as the tetrahydrofuran itself, a commercially available product may be used as it is or may be purified and used.

A suitable example of the separation column used in GPC is a packed column of vinyl alcohol copolymer, and an ultraviolet absorption detector is used as the detection means.

The fourth aspect of the present invention is a method for measuring the molecular weight distribution of hydroxypropylmethylcellulose by GPC, which comprises dissolving hydroxypropylmethylcellulose in a mixed solution of chloroform and methanol and then mixing the dissolved solution with chloroform and methanol. The solution is subjected to GPC using the mobile phase as a mobile phase to measure the molecular weight distribution of hydroxypropylmethyl cellulose.

Here, the mixing ratio of chloroform and methanol is such that chloroform is the main ratio, for example, 7 / 3-
7/6 is preferable. As chloroform and methanol, commercially available products may be used as they are, or they may be purified and then used.

To dissolve hydroxypropylmethylcellulose in a mixed solution of chloroform and methanol,
For example, hydroxypropylmethylcellulose may be placed in a screw tube and an appropriate amount of mixed solution may be added thereto, but the method is not limited. The amounts of chloroform and methanol required for dissolution obviously depend on the sample amount, but the proportion of dissolved hydroxypropylmethylcellulose is 0.4% by weight.

A suitable example of the separation column used in GPC is a packed column of vinyl alcohol copolymer, and the detection means is, for example, a differential refractive index detector.

[0025]

According to the present invention, the molecular weight of a high molecular weight substance, which has been difficult to measure the molecular weight distribution, can be obtained by fractionating and collecting the eluent from GPC for a solution of polymethacrylic acid homopolymer. The distribution can be measured.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An apparatus configuration for carrying out the method of the present invention will be described with reference to the drawings. FIG. 1 is an example of an apparatus for carrying out the method of the present invention, 1 is a mobile phase reservoir, 2 is a liquid feed pump, 3 is a manual injector, 4 is a column, 5 is a column oven, and 6 is an ultraviolet absorption detector. Alternatively, the differential refractive index detector and 7 are data processing devices.

At the time of analysis, the mobile phase is made to flow in advance from the mobile phase storage tank 1 by the pump 2 to create a steady state.
Next, the sample is injected from the manual injector 3.
The injected sample is sent to the column 4 in the column oven 5 by the mobile phase and detected by the detector 6. This data is processed by the data processing device 7, and quantitative calculation is performed. Using the above apparatus, analysis was performed under the following analysis conditions.

<Experimental Example 1: Polymethacrylic acid homopolymer
-Molecular weight distribution measurement > (1) Preparation of sample Dissolve 20 mg of polymethacrylic acid homopolymer in 5 ml of mobile phase (the following) and use a membrane filter (pore size:
0.45 μm). Next, 200 μl of the filtrate is added to G
Inject into PC.

(2) Analytical conditions Column: Asahipak GS-310H (manufactured by Shimadzu Corporation) (7.6 mm ID × 250 mm) Mobile phase: A: Methanol B: 50 mM phosphate buffer (pH 9.3) A: B = 3: 2 Flow rate: 0.5 ml / min Temperature: 40 ° C. Detector: RID-6A (differential refractive index detector manufactured by Shimadzu Corporation) Sensitivity: 64 × 10 ⁻⁶ RIUFS Polarity: + (3) Analysis results The results of analysis under the above analysis conditions are shown in FIG. It can be seen from FIG. 2 that the molecular weight distribution of the polymethacrylic acid homopolymer can be easily measured. The vertical axis in FIG. 2 represents the signal intensity and the horizontal axis represents the holding time.

<Experimental Example 2: Molecular weight of polyetherketone
Distribution measurement > (1) Preparation of sample 15 mg of polyether ketone was used as mobile phase (the following) 1
Dissolve in 0 ml and use a membrane filter (pore size: 0.45
μm). The filtrate is further diluted 10 times with chloroform. Next, 50 μl of the diluent is injected into GPC.

(2) Analytical conditions Column: Shim-pack GPC-80MC
(Manufactured by Shimadzu Corporation) (8.0 mm ID × 300 mml) Mobile phase: A: Dichloroacetic acid B: Chloroform A: B = 1: 9 Flow rate: 0.7 ml / min Temperature: 40 ° C. Detector : SPD-10A (Ultraviolet absorption detector manufactured by Shimadzu Corporation) Sensitivity: 0.512AUFS Wavelength: 290 nm (3) Analysis results The analysis results under the above analysis conditions are shown in FIG. From FIG. 3, it can be seen that the molecular weight distribution of polyetherketone can be easily measured. In FIG. 3, the vertical axis represents the signal intensity and the horizontal axis represents the holding time.

<Experimental Example 3: Polystyrene latex content
Measurement of molecular weight distribution > (1) Preparation of sample 200 μl of filtrate is injected into GPC.

(2) Analytical conditions Column: Asahipak GSM-700H, GS-
510H, 310H (manufactured by Shimadzu Corporation) (7.6 mm ID × 250 mm each) Mobile phase: Tetrahydrofuran Flow rate: 1.0 ml / min Temperature: 40 ° C. Detector: SPD-6A (UV absorption detector) (Manufactured by Shimadzu Corporation) Sensitivity: 0.64 AUFS Wavelength: 254 nm (3) Analysis results The results of analysis under the above analysis conditions are shown in FIG. It can be seen from FIG. 4 that the molecular weight distribution of polystyrene latex can be easily measured. In FIG. 4, the vertical axis represents signal intensity and the horizontal axis represents retention time.

<Experimental Example 4: Hydroxypropylmethylse
Measurement of molecular weight distribution of lulose > (1) Preparation of sample Dissolve 20 mg of hydroxypropylmethylcellulose in 5 ml of mobile phase (the following) and filter with a membrane filter (pore size: 0.45 μm). Next, the filtrate 200
Inject μl into GPC.

(2) Analytical conditions Column: Asahipak GSM-700H (Co., Ltd.)
(Manufactured by Shimadzu Corporation) (7.6 mm ID × 250 mm) Mobile phase: Chloroform / methanol (3/2) Flow rate: 1.0 ml / min Temperature: 40 ° C. Detector: RID-6A (differential refractive index detector (Manufactured by Shimadzu Corporation) Sensitivity: 128 × 10 ⁻⁶ RIUFS Polarity: + (3) Analysis results FIG. 5 shows the results of analysis under the above analysis conditions. It can be seen from FIG. 5 that the molecular weight distribution of hydroxypropylmethyl cellulose can be easily measured. The vertical axis in FIG. 5 represents the signal strength,
The horizontal axis represents the retention time.

[0036]

According to the present invention, it is possible to accurately and efficiently measure the molecular weight distribution of a polymer substance such as polymethacrylic acid homopolymer which could not be accurately measured in the prior art. Furthermore, the obtained molecular weight distribution has a special effect that quality control and performance evaluation of these substances can be easily performed.

[Brief description of drawings]

FIG. 1 shows an apparatus for implementing the arrangement of the invention.

FIG. 2 is a diagram showing the results of measuring the molecular weight distribution of polymethacrylic acid homopolymer.

FIG. 3 is a diagram showing the results of measuring the molecular weight distribution of polyetherketone.

FIG. 4 is a diagram showing the results of measuring the molecular weight distribution of polystyrene latex.

FIG. 5 is a diagram showing the results of measuring the molecular weight distribution of hydroxypropylmethyl cellulose.

[Explanation of symbols] 1: Mobile phase storage tank 4: Analytical column 6: Detector

Claims (4)

[Claims] 1. A method for measuring a molecular weight distribution of a polymethacrylic acid homopolymer by gel permeation chromatography, wherein the polymethacrylic acid homopolymer is dissolved in a mixed solution of methanol and a phosphate buffer, and the dissolved solution is methanol. A method for measuring a molecular weight distribution using a gel permeation chromatograph, characterized by measuring the molecular weight distribution of a polymethacrylic acid homopolymer by subjecting it to a gel permeation chromatograph using a phosphate buffer as a mobile phase. 2. A method for measuring the molecular weight distribution of polyetherketone by gel permeation chromatography, comprising:
After dissolving polyetherketone with dichloroacetic acid by heating, dilute it with chloroform, and subject the diluted solution to gel permeation chromatography using a mixed solution of dichloroacetic acid and chloroform as a mobile phase to determine the molecular weight distribution of polyetherketone. A method for measuring a molecular weight distribution using a gel permeation chromatograph characterized by measuring. 3. A method for measuring the molecular weight distribution of polystyrene latex by gel permeation chromatography, wherein the polystyrene latex solution is subjected to gel permeation chromatography using tetrahydrofuran as a mobile phase to measure the molecular weight distribution of polystyrene latex. A method for measuring a molecular weight distribution using a gel permeation chromatograph, characterized by: 4. A method for measuring the molecular weight distribution of hydroxypropylmethylcellulose by gel permeation chromatography, which comprises dissolving hydroxypropylmethylcellulose in a mixed solution of chloroform and methanol,
The solution was subjected to gel permeation chromatography using a mixed solution of chloroform and methanol as a mobile phase to measure the molecular weight distribution of hydroxypropylmethyl cellulose. Molecular weight distribution using gel permeation chromatography Measurement method.