可见吸收光谱法测定维生素B12  

Determination of vitamin B12 by visible absorption spectroscopy

作　　者：何树华[1] 何玲[1] 陈明媛 江虹[1] HE Shu-hua;HE Ling;CHEN Ming-yuan;JIANG Hong(College of Chemistry and Chemical Engineering,Collaborative Innovation Center for Green Development in Wuling Mountain Areas,Yangtze Normal University,Chongqing 408100)

机构地区：[1]长江师范学院化学化工学院长江师范学院武陵山片区绿色发展协同创新中心

出　　处：《分析试验室》2019年第12期1465-1469,共5页Chinese Journal of Analysis Laboratory

基　　金：重庆市教委科技基金资助项目(KJ121307);长江师范学院科技基金资助项目(2018CXX111)资助

摘　　要：探讨了溴甲酚绿与维生素B 12间的缔合反应条件、吸收光谱特征及共存物质影响,建立了测定药物中维生素B 12的高灵敏可见光区吸收光谱法。在pH 6.18的弱酸性介质中,维生素B 12与溴甲酚绿以静电引力作用生成离子缔合物,在400~700 nm范围内,产生1个较强的正吸收峰(448 nm)和1个较强的负吸收峰(616 nm),在此二波长处,维生素B 12的质量浓度在2.0~13.6μg/mL内与体系的吸光度绝对值(│A│)呈线性关系,服从朗伯-比尔定律,表观摩尔吸光系数(κ)分别为1.37×105 L·mol-1·cm-1(448 nm)和3.31×105 L·mol-1·cm-1(614 nm)。当以616 nm作为参比波长,448 nm作为测定波长时,表观摩尔吸光系数(κ)达4.68×105 L·mol-1·cm-1。当将灵敏度最高的双波长法用于药物中维生素B 12含量的测定时,加标回收率为98.2%~103%,相对标准偏差(RSD,n=5)为2.1%~2.5%。The association reaction conditions,absorption spectrum characteristics and coexisting substances influence of bromocresol green and vitamin B 12 were studied.A high-sensitive method based on visible absorption spectrometry for the determination of vitamin B 12 in drugs was established.In a weakly acidic medium of pH 6.18,vitamin B 12 could form an ion association complexes with bromocresol green by electrostatic attraction.Within the range of 400-700 nm,a strong positive absorption peak(448 nm)and a strong negative absorption peak(616 nm)were generated.At such two wavelengths,the mass concentration of vitamin B 12 were linearly related to the absolute value of the absorbance of the system(│A│)in the range of 2.0 to 13.6μg/mL and the follows lambert-beer's law.The apparent molar absorptivity(κ)were 1.37×105 L·mol-1·cm-1(448 nm)and 3.31×105 L·mol-1·cm-1(614 nm),respectively.Using 616 and 448 nm as the reference and measurement wavelength,respectively,the apparent molar absorptivity(κ)could reach 4.68×105 L·mol-1·cm-1.Undergo the most sensitive dual-wavelength model,the determination of vitamin B 12 in the drugs was performed,the spiked recoveries were from 98.2%to 103%,with the relative standard deviations(RSDs,n=5)of 2.1%-2.5%.

关 键 词：溴甲酚绿 维生素B12 吸收光谱法 

分 类 号：O657.3[理学—分析化学] R917[理学—化学]