微生物法测定肠内营养粉剂中微量维生素B_(12)的含量

Determination of trace vitamin B_(12) in enteral nutrition powder by microbiological method

目的建立微生物法测定肠内营养粉剂中微量维生素B_（12）的含量。方法以莱士曼氏乳酸杆菌为实验菌,在测定用培养基中供给除维生素B_（12）以外的所有营养成分,（36±1）℃培养19~20 h,采用比浊法测定。结果维生素B_（12）在0.001~0.010 ng/mL浓度范围内线性关系良好,肠内营养粉剂中维生素B_（12）的含量为2.9μg/100 g。结论该方法检测结果准确、可靠,适用于肠内营养粉剂中微量维生素B_（12）的含量测定。

Objective To establish a method for the determination of trace vitamin B_（12） in enteral nutrition powder by microbiological method.Methods The test organism was Lactobacillus leichmamii.The medium without vitamin B_（12） was used as assay medium.The sample were incubated for 19~20 h at the temperature of（36±1） ℃ and measured by microbial turbidimetric method.Results Vitamin B_（12） had a good linear relationship in the range of 0.001~0.010 ng/mL,and the content of vitamin B_（12） in enteral nutrition powder was2.9 μg/100 g.Conclusion This method is accurate and reliable,and suitable for the assay of trace vitamin B_（12）in enteral nutrition powder.