Feng J, Melcher A H, Brunette D M, Moe H K
In Vitro. 1977 Feb;13(2):91-9. doi: 10.1007/BF02615072.
The method of Deutsch and Weeks was modified to provide a reliable and reasonably quick method for assaying the L-ascorbic acid content of culture medium. The modified method was used to determine the decay of L-ascorbic acid under various conditions of culture and the concentration of the vitamin in commercially prepared media. The half-life of L-ascorbic acid in a modified New circulator gassed with 95% O2 + 5% CO2 was 1.5 hr.; and when gassed with 20% O2 + 5% CO2 + 75% N2, about 2 hr. In Petri dishes gassed with 20% O2 + 5% CO2 + 75% N2, the half-life of L-ascorbic acid was 0.9 hr. About 4% of the L-ascorbic acid was lost per day when medium was stored at 0 degrees C and about 9% per day when stored at 5 degrees C. When medium with an initial content of 300 microng per ml was stored at room temperature, the half-life was found to be 15.5 hr. The L-ascorbic acid in five commercially available media, which contain the vitamin in their formulations, was assayed immediately after their delivery to the laboratory. The values of L-ascorbic acid measured in these media were in all cases far lower than prescribed. A continuous-flow organ culture system has been designed which allows the provision of a relatively constant level of L-ascorbic acid to explant by taking advantage of the slow oxidation of L-ascorbic acid at 0 degrees C.
对多伊奇和威克斯的方法进行了改进，以提供一种可靠且相对快速的方法来测定培养基中L - 抗坏血酸的含量。改进后的方法用于确定在各种培养条件下L - 抗坏血酸的衰减情况以及市售培养基中该维生素的浓度。在以95% O₂ + 5% CO₂ 充气的改良型新循环器中，L - 抗坏血酸的半衰期为1.5小时；当以20% O₂ + 5% CO₂ + 75% N₂ 充气时，半衰期约为2小时。在以20% O₂ + 5% CO₂ + 75% N₂ 充气的培养皿中，L - 抗坏血酸的半衰期为0.9小时。培养基在0℃储存时，L - 抗坏血酸每天约损失4%，在5℃储存时每天约损失9%。当初始含量为每毫升300微克的培养基在室温下储存时，发现其半衰期为15.5小时。对五种市售且配方中含有该维生素的培养基，在送达实验室后立即测定其L - 抗坏血酸含量。在这些培养基中测得的L - 抗坏血酸值在所有情况下都远低于规定值。设计了一种连续流动器官培养系统，该系统利用L - 抗坏血酸在0℃时的缓慢氧化，能为外植体提供相对恒定水平的L - 抗坏血酸。
