JPS5819546A - Bath liquid heating type melting point measuring apparatus - Google Patents

Abstract

PURPOSE:To achieve a highly accurate measurement by an indirect method of heating a sample through a bath liquid by making a temperature sensing section of a thermometer equal to a glass tublet containing the sample in the shape and the size. CONSTITUTION:A glass tube 1 contains a sample 2 and a glass tublet 3 identical to the glass tublet 1 has a temperature measuring contact 4 of a thermocouple made of a fine strand.A heating bath liquid 5 is placed in a transparent vessel 6. The bath liquid 5 is heated with a burner 7 while both the tublets 1 and 3 are heated on the same condition. It is checked visually how the sample is melted and the temperature is measured with a thermometer 10 provided following the tublets. As the temperature sensing section of the thermometer and the sample are subject to the same condition, a highly accurate measurement of melting points can be done.

Description

[Detailed Description of the Invention] In order to accurately measure the melting point, the temperature sensitive part of the temperature needle is brought into direct contact with the sample, and during the melting and solidification processes,
It is necessary to ensure that the temperature remains constant for a certain amount of time. However, for pharmaceutical manufacturing, etc., it is considered desirable to be able to use a small amount of sample, even if the accuracy is somewhat poor.

In the recent 9th revised Japanese Pharmaceutical Law, the melting point measurement method is stipulated as follows. A powder sample is placed in a hard glass capillary tube with an inner diameter of 0.8 to 1.2 mm, a wall thickness of 0.2 to 0.3 m, and a length of 120 mm, closed at one end.

Place the thin tube containing the sample and the mercury thermometer into the silicone oil bath in a transparent container, place the portion of the thin tube containing the sample near the bulb of the mercury thermometer, and heat it from the outside. , the melting of the sample in the capillary tube is confirmed with the naked eye, and the temperature indicated by the mercury thermometer at that time is the melting point of the sample. As stated above, the temperature of the sample is continuously measured and the temperature is kept constant for a certain period of time during the melting and solidification processes. This is an indirect method in which the sample is heated through a bath liquid.
This article concerns a melting point measuring device that has been improved to enable more accurate measurements than previous ones.

The method of heat conduction and heat capacity between a glass capillary containing a sample and a mercury thermometer are markedly different, so the way the temperature rises due to indirect heating is markedly different. This is thought to be the main reason for the difference in temperature between the sample and the sample. The main improvement lies in this point. In the device of the present invention, the main focus is to make the shape, size, etc. of the temperature sensing part of the thermometer as similar as possible to the glass tube containing the sample. 1 shows an embodiment of the heating section of the device of the present invention. 1 is sample 2
3 is preferably the same glass tube as 1, and if you put a powder similar to the sample but with a high melting point in the tube 3 of the thermocouple with a thin wire, it will be even better. good.

Care should be taken to place 1 and 3 close to each other so that the heating conditions are as similar as possible.

Heating is not limited to using the gas burner 7, but may be performed using any appropriate method. Also, the bath liquid is not limited to silicone oil. The part is not limited to the temperature measuring junction 4 of the thermocouple,
Although a small temperature-sensing part such as a thermistor may be used, the temperature-measuring junction 4 of a thermocouple made of thin wire is superior to a thermistor as follows: O j) The heat quantity of the ItA hot part is small.

++　　　　The temperature range that can be measured is wide.

111) It can be a continuous thermometer.

In particular, if you connect it to a resistance thermometer to use it as a connection thermometer and set the connection temperature to a temperature close to the temperature to be measured, you can make accurate measurements. In the figure, 8 is the connection part with resistance thermometer 9, and 10 is This is the circuit and instrument part of a continuous thermometer.

[Brief explanation of the drawing]

The drawing is a sectional view showing an embodiment of the bath liquid heating type melting point measuring device according to the present invention. ■ Glass capillary tube 2, sample 3, glass capillary tube 4, temperature measuring junction of thermocouple 5, bath liquid 6, transparent container 7, gas burner 8, connecting part 9 of the connecting hygrometer, resistance thermometer 10, Tsuji・Hygrometer circuit and instrumentation patent applicant Shisaka Institute Co., Ltd. Agent (7524) Shotabe Mogami

Claims (1)

[Claims] Insert a small temperature-sensing part, such as a temperature-measuring junction of a thin wire thermocouple, into a glass tube of the same shape and size as the one in which the sample is placed, and place the glass tube containing the sample and the blood sample in a heating bath. A bath liquid heating type melting point measuring device that heats both sets of tubes under the same conditions as much as possible, visually confirms the melting of the sample, and uses the temperature measured with a thermocouple or the like at that time as the temperature of the sample.