echemi logo
Product
  • Product
  • Supplier
  • Inquiry
    Home > Active Ingredient News > Drugs Articles > Significance of eutectic point and melting point in freeze-drying process

    Significance of eutectic point and melting point in freeze-drying process

    • Last Update: 2017-03-14
    • Source: Internet
    • Author: User
    Search more information of high quality chemicals, good prices and reliable suppliers, visit www.echemi.com
    Freeze drying technology is a method to sublime the watery materials in vacuum state after pre freezing The original chemical and biological characteristics of the dried materials are basically the same, which is easy to keep for a long time It is an excellent drying method, widely used in food, biological products, medicine, chemical industry, material preparation and other fields In the process of freeze-drying, the eutectic point and melting point are two important parameters of Zui The pre freezing temperature of the material should be 5-10 ℃ lower than the eutectic point of the material Ensure that the material is completely frozen If the pre freezing temperature is too low, the freezing time will be prolonged, the production cost will be increased, and the time and energy will be wasted If the pre freezing temperature is higher than the eutectic point, the moisture in the material cannot be completely frozen, so that the moisture can not be completely sublimated in the form of ice, and the drying process is prone to local boiling and foaming Such as Lead to material shrinkage and shape loss and other quality problems In addition, the dissolved solute contained in the unfrozen water can not be resolved in place during the drying process, but with the internal water moving to the surface of the material, the surface hardening phenomenon of the freeze-dried products appears The eutectic point of a material is the temperature at which the completely frozen material gradually heats up and the ice crystals inside the material begin to melt During sublimation drying, the material temperature should not be higher than its common melting point, otherwise the material will melt, leading to material boiling, bubble, inflation expansion or drying shrinkage in the material, which will affect the quality of freeze-dried products Therefore, it is of great significance to determine the eutectic point and melting point accurately for the formulation of freeze-drying process plan and the optimization control of freeze-drying process If you want to buy the lyophilizer produced by Beijing Songyuan Huaxing, please read the operation manual carefully before use, or direct our technical personnel The measurement methods of eutectic point and melting point of materials include resistance method, differential scanning calorimetry (DSC), low temperature microscope direct observation method and numerical formula calculation method Among them, the resistance measurement method is easy to implement and popularize The resistance measurement method is based on the ionization theory of S.A Arrhenius: when there are impurities in the water, some impurities will be decomposed into electric ions At this time, the water is conductive When the temperature drops, the resistance of the solution will gradually increase When the solution is completely solidified into a solid, the ions in the solution will completely lose their ability of free movement, and the resistance will suddenly increase At this time, the temperature is the eutectic point 。 In the process of heating up completely frozen materials, the temperature when the resistance suddenly decreases is the eutectic point Therefore, the eutectic point or melting point of the material can be obtained by recording the change data of temperature and resistance and analyzing the recorded data.
    This article is an English version of an article which is originally in the Chinese language on echemi.com and is provided for information purposes only. This website makes no representation or warranty of any kind, either expressed or implied, as to the accuracy, completeness ownership or reliability of the article or any translations thereof. If you have any concerns or complaints relating to the article, please send an email, providing a detailed description of the concern or complaint, to service@echemi.com. A staff member will contact you within 5 working days. Once verified, infringing content will be removed immediately.

    Contact Us

    The source of this page with content of products and services is from Internet, which doesn't represent ECHEMI's opinion. If you have any queries, please write to service@echemi.com. It will be replied within 5 days.

    Moreover, if you find any instances of plagiarism from the page, please send email to service@echemi.com with relevant evidence.