JPH0526862A - Method for analyzing distribution of molar weight of hydroxypropylmethylcellulosephthalate - Google Patents

Abstract

PURPOSE:To enable a title item to be established and its quality control and performance evaluation to be performed easily by using a mixed liquid of chloroform and methanol as a solvent medium. CONSTITUTION:After dissolving hydroxypropylmethylcellulosephthalate in a mixed solution of chloroform and methanol, this liquid solution is subjected to gelpermeationchromatograph (GPC) with the mixed solution of chloroform and methanol as a mobile phase, thus enabling the distribution of molar weight to be distributed. As a pretreatment, a sample is allowed to be dissolved in the mobile phase and is filtered by a membrane filter. In the case of analysis, the mobile phase is allowed to flow from a mobile phase storage flow tank 1 to a pump 2, thus enabling a steady state to be created. Then, a sample which is dissolved from a manual injector 3 is poured. The poured sample is sent to a column 4 within a column oven 5 by the mobile phase, the distribution of molar weight is detected by a differential refractive index detector 6 and is processed by a processing device 7, thus enabling the molar weight to be calculated.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for analyzing hydroxypropyl methylcellulose phthalate. More specifically, gel permeation chromatograph (hereinafter,
GPC), which is suitable for quality control and performance evaluation of hydroxypropylmethylcellulose phthalate.

[0002]

BACKGROUND OF THE INVENTION Hydroxypropyl methylcellulose phthalate has chemical resistance and is used for materials such as films and coatings.

Therefore, quality control, performance evaluation, etc. are required for use in such materials, and it is desired to measure the molecular weight distribution of hydroxypropylmethyl cellulose phthalate.

[0004]

However, conventionally, there is no suitable solvent for dissolving hydroxypropylmethylcellulose phthalate, and for example, even if an attempt is made to measure the molecular weight distribution of hydroxypropylmethylcellulose phthalate by GPC or liquid chromatography. , It was difficult.

Therefore, an object of the present invention is to provide a molecular weight distribution analysis method for hydroxypropylmethylcellulose phthalate by finding a suitable solvent for dissolving hydroxypropylmethylcellulose phthalate.

[0006]

Means for Solving the Problems The inventors of the present invention have made extensive studies in order to solve the above problems, and as a result, found that hydroxypropylmethylcellulose phthalate was dissolved in a mixed solution of chloroform and methanol. I arrived.

That is, the present invention is characterized in that after hydroxypropylmethylcellulose phthalate is dissolved in a mixed solution of chloroform and methanol, the solution is subjected to GPC using a mixed solution of chloroform and methanol as a mobile phase for analysis. Is a molecular weight distribution analysis method for hydroxypropylmethyl cellulose phthalate.

The mixing ratio of chloroform and methanol here is mainly chloroform, for example 7/3 to 5 /.
5 is preferable. As the chloroform or methanol, commercially available products may be used as they are, or they may be purified and then used.

To dissolve hydroxypropylmethylcellulose phthalate in a mixed solution of chloroform and methanol, for example, it is sufficient to put hydroxypropylmethylcellulose phthalate in a beaker and add an appropriate amount of the mixed solution to the beaker. Absent. The amounts of chloroform and methanol required for dissolution obviously depend on the sample amount, but the ratio of dissolved hydroxypropylmethylcellulose phthalate is about 0.4% by weight.

When a mixed solution of chloroform and methanol is added to hydroxypropylmethylcellulose phthalate, hydroxypropylmethylcellulose phthalate is dissolved and subjected to GPC. To attach to GPC,
A known sample introduction device can be used, which allows a predetermined amount of solution to be injected into the GPC.

The solution injected into the GPC is applied to a separation column using a mixed solution of chloroform and methanol 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, and for example, a packed column of vinyl alcohol copolymer gel can be mentioned as a suitable example.

As the GPC detecting means, for example, a differential refractive index detector is used. This is because hydroxypropyl methylcellulose phthalate has no absorption in the ultraviolet.

[0014]

According to the present invention, the molecular weight distribution of the sol component of hydroxypropylmethylcellulose phthalate can be obtained by fractionating and collecting the eluent from GPC for the solution of hydroxypropylmethylcellulose phthalate.

[0015]

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 shows 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 a differential refractive index detection. The container 7 is a data processing device.

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 the differential refractive index detector 6 detects the molecular weight distribution. This data is processed by the data processor 7 to calculate the molecular weight.

Using the above apparatus, analysis was conducted under the following analysis conditions. (1) Sample pretreatment Hydroxypropyl methylcellulose phthalate 20m
g is dissolved in 5 ml of mobile phase (shown below) and filtered through a membrane filter (pore size: 0.45 μm). next,
Inject 200 μl of the filtrate into the GPC.

(2) Analytical conditions Column: Asahipak GSM-700H (Co., Ltd.)
(Manufactured by Shimadzu) (each 7.6 mm ID × 500 mm) Mobile phase: Chloroform / methanol (6/4) Flow rate: 1.0 ml / min Temperature: 40 ° C. Detector: RID-6A (differential refractive index detection Kikai Co., Ltd. Shimadzu Corporation Sensitivity: 128 × 10 ^-6 RIUFS Polarity: + (3) Analysis results The results of analysis under the above analysis conditions are shown in FIG. The peak in the figure is the peak of hydroxypropylmethylcellulose phthalate. From this figure, it is understood that according to the present invention, hydroxypropylmethylcellulose phthalate can be analyzed with high sensitivity. The vertical axis in FIG. 2 represents the signal intensity and the horizontal axis represents the holding time.

[0019]

According to the present invention, the molecular weight distribution of hydroxypropylmethylcellulose phthalate can be measured efficiently and accurately, and the obtained molecular weight distribution facilitates the quality control and performance evaluation of hydroxypropylmethylcellulose phthalate. It has the special effect that it can be done.

[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 analysis by the method of the present invention.

[Explanation of symbols]

 1: Mobile phase storage tank 4: Analytical column 6: Detector

Claims (1)

Claims: 1. Dissolving hydroxypropylmethylcellulose phthalate in a mixed solution of chloroform and methanol, and then subjecting the solution to a gel permeation chromatograph using a mixed solution of chloroform and methanol as a mobile phase. A method for analyzing the molecular weight distribution of hydroxypropylmethyl cellulose phthalate, characterized by the following analysis.