建立了在线固相萃取-高效液相色谱直接检测功能饮料中V B12的方法,采用将双泵技术及阀切换技术结合在线固相萃取技术,将功能饮料中的大部分干扰物质去除后,对样品进行分析,降低了干扰,提高了灵敏度。在线固相萃取技术是一种简单、灵敏、高效的V B12检测手段,可以不需要对功能饮料离线处理,直接对V B12进行检测,检出限为0.54μg/L,回收率为101.29%。

A method for rapid determination of Vitamin B 12 in functional drinks by online SPE coupled with dual gradient high performance liquid chromatography and dual valves was developed. First,an aliquot of 2. 5 mL functional drink sample was injected directly into the SPE column with loading pump,and Vitamin B 12 was concentrated in the SPE column,while most interfering material was removed; After cleanup,the valve was switched and retained Vitamin B 12 was flushed to analytical column. The online SPE column was Thermofisher IonPac NG1( 4 mm × 35 mm), the analysis column was Thermofisher Acclaim PAII C18( 4. 6 × 150 mm,5 μm),two columns were used at 30℃. The mobile phase was a gradient mixer of acetonitrile and 0. 025% TFA( volume to volume),and the detection wavelength was set at 220 nm. The injection volumes were 1 000 μL for each run. Based on the above optimizing chromatogram condition,Vitamin B 12 was separated satisfactorily. The limitation of detection could be 0. 54 μg / L,the recovery could be 101. 29%.