尺寸排阻色谱电感耦合等离子体质谱联用测定功能饮料、多维片及奶粉中维生素B_(12)

Determination of Vitamin B_(12) in Functional Drink,Multivitamin Tablets, Infant Milk Powder by Size Exclusion Chromatography-Inductively Coupled Plasma Mass Spectrometry

建立了固相微萃取（SPE）柱净化,尺寸排阻色谱-电感耦合等离子体质谱（SEC-ICP-MS）联用测定功能饮料、多维片和婴儿奶粉中维生素B12含量的方法,方法检出限为0.4μg/L,维生素B12在1.0~150μg/L范围内线性良好,回归系数R〉0.999。实验表明,乙腈作为维生素B12标准品溶剂可改善维生素B12的色谱行为,用乙腈作为SPE柱洗脱液比甲醇效果好。在婴儿奶粉的前处理过程中,三氯甲烷作为蛋白沉淀剂得到的维生素B12回收率较高。功能饮料、多维片和3种婴儿奶粉的检测结果与商品标示值接近,相对标准偏差RSD均小于5%（n=6）,功能饮料、多维片的平均加标回收率为97%和90%,5种奶粉的平均加标回收率范围为88%~92%,表明本方法能够满足日常分析的要求。

A method based on solid phase extraction （SPE） with size exclusion chromato coupled plasma mass spectrometry （SEC-ICP-MS） was developed for the determination graphy-inductively of vitamin B12 in functional drink, multivitamin tablets and infant milk powder. The lowest detecting limit for vitamin B12 was 0. 4 μg/L. When the concentration of vitamin B12 ranged from 1.0 to 150 μg/L, the correlation coefficient was above 0. 999. Under the optimum conditions, the chromatographic behavior of vitamin B12 could be improved by using acetonitrile as solvent. Still, acetonitrile could play a better performance than methanol as SPE eluent. CHC13 was a proper reagent for infant milk powder protein precipitation, which brought a better recovery rate for vitamin B12. The vitamin B12 data of functional drink, multivitamin tablets and infant milk powder were coincident with their pack marks. The relative standard deviations （RSD） for these samples were all below 5% and the average recovery rates were all above 88%. The method was suitable for daily analysis.