Development Of Tandem Microscale Carbon Fiber Columns Fractionation System And Its Applications In The Analysis Of Traditional Chinese Medicines

Traditional Chinese medicines (TCMs) have been used in China more than four millenniums, and have become more popular around the world during the last decade. TCMs are commonly considered to operate due to the synergistic effects of all the major and minor components in the medicines, hence sensitive and comprehensive analytical techniques are needed to acquire a better understanding of the pharmacological basis of the TCMs. However, TCMs is a multi-component system from high polarity to weak polarity, and only a few compounds are known for the pharmaceutical effects. Though high performance liquid chromatography (HPLC) is one of the most effective separation methods, TCMs are far too complex to be adequately resolved by current HPLC methods due to its limitations in selectivity and peak capacity. For direct MS analysis, suitable sample pretreatment is required prior to direct MS analysis for the cleanup of matrix. Hence, on-line tandem carbon fiber columns with MS/MS system was realized for the first time and applied in the comprehensive analysis of traditional Chinese medicines. We use two different carbon fiber as packing material to form a novel micro-column, which has been proved the feasibility by off-line coupled with HPLC-MS/MS system. This system can divide a TCM extract into three fractions with SPE according to corresponding chromatographic polarity, followed by MS/MS system for the analysis of each fraction. With the online combination of the tandem columns with MS/MS system, the analytes desorbed from the column according to the polarity. Then the fractions were directly ionized and transferred into MS for detection, thus rapid determination was achieved. The method has satisfactory accuracy (55%-92%) and reproducibility (RSD=0.23%-21.65%) without the isotope-labeled internal standard. The proposed method has been applied to analyze Schisandrae Chinensis, various polarity compounds including organic acids, lignans could be detected. The total time can be limited to 10 minutes, so the present study showed that the system could be a rapid and versatile method that allows a wide range of applications.