Simultaneous determination of phytochemicals and low-weight organic acids in Sophora japonica bud and premium noni juice through column-switching liquid chromatography connected with ion chromatography system

In this work, a liquid chromatography connected with an ion chromatography by the column-switching technique was developed for the simultaneous determination of three phytochemicals (scopoletin, rutin, and quercetin), three anions (chloride, sulfate, and phosphoric), and seven organic acids (lactic, acetic, propionic, formic, malic, oxalic, and citric acid) in Chinese traditional herbs, S. japonica bud and premium noni juice. A concentration column was used to collect organic acids and anions, and then the concentrated analytes were eluted to an analytical column by column-switching technique in which target analytes could be separated successfully and detected simultaneously within 70 min. This method showed good linearity with the linear correlation coefficients in the range of 0.9971–1.0000. The relative standard deviations of the peak areas were all less than 5.63% (n = 6). The limits of detection (LOD, S/N = 3) of anions and organic acids were in the range of 0.0006–0.0857 mg/L, whereas phytochemicals were in the range of 0.0123–0.0197 mg/L. Recoveries were in the range of 86.53–117.01% for the spiked sample. This method was successfully applied to the determination of the low-weight organic acids and phytochemicals in Chinese traditional herbal medicines, S. japonica bud and premium noni juice.