Determination of Moisture Content in Freeze Dried Protein by Thermogravimetric Analyzer

Freeze dried protein, with its low-temperature drying properties, can largely retain its biological activity and is widely used in fields such as biopharmaceuticals and diagnostic reagents. Moisture content is a key indicator that affects the stability, storage life, and efficacy of freeze-dried proteins - excessive moisture can lead to protein aggregation and degradation, while insufficient moisture may affect the protein reconstitution effect. Therefore, using thermogravimetric analysis (TGA) to monitor the mass changes during sample heating can accurately quantify volatile components such as moisture, thereby improving the stability of freeze-dried proteins and extending their storage time.

1、 Operation steps of the experiment

1. Measuring instruments:DZ-TGA201 Thermogravimetric Analyzer

2. Sample preparation: Take freeze-dried protein samples and grind them to a uniform powder to avoid severe grinding that may damage the protein structure. Place the ground sample in a vacuum drying oven and pre treat it at 30 ℃ for 30 minutes to remove any air moisture adsorbed on the surface. Cool it to room temperature and set it aside.

3. After the instrument calibration is completed, place the crucible with the sample into the furnace and set the experimental parameters. Heat it up to 105 ℃ at a rate of 10 ℃/min and maintain the temperature for 60 minutes. The supporting analysis software will collect the measurement spectrum in real time and record the quality change curve.

4. Measurement chart:

5. Graph analysis:

Take about 10mg of the test sample and measure it using the thermogravimetric method (TG) according to the General Rules 0661 "Thermal Analysis Method" in the 2020 edition of the Pharmacopoeia. The heating procedure is to raise the temperature from room temperature to 105 ℃ at a rate of 10 ℃/min and maintain it for 60 minutes. Weight loss refers to the moisture content, which should meet the corresponding requirements. A sample with a moisture content of less than 5% is considered qualified. As shown in the above figure, after being kept at 105 ℃ for 70 minutes, the weight loss of the freeze-dried protein tested was 3.88%, indicating that the moisture content in the protein was 3.88%, which meets the requirements.

In this experiment, the measuring instrument used was the DZ-TGA201 thermogravimetric analyzer newly launched by Nanjing Dazhan, which can automatically lift and lower. Compared with traditional thermogravimetric analyzers, it has high measurement accuracy, automated operation, and can be effectively applied to quality monitoring and finished product inspection in the freeze-dried protein production process, providing an effective and feasible technical solution for quality control in the biopharmaceutical industry.