Determination of Shikimic Acid in Fruits of Illicium Species and Various Other Plant Samples by LC-UV and LC-ESI-MS

A simple and specific analytical method for the quantitative determination of shikimic acid from the methanol extract of the fruits of Illicium species and from various plant samples was developed. The LC-UV separation was achieved by reversed-phase chromatography on a C18 column with potassium dihydrogen phosphate and methanol as the mobile phase. In the LC-MS method, the separation was achieved by a C12 column using water and acetonitrile, both containing 0.1% acetic acid as the mobile phase. The methods were successfully used to study the percentage compositions of shikimic acid present in nine species of Illicium and various other plant samples. The detector response was linear with concentrations of shikimic acid in the range from 1.0-500.0 mu g mL(-1) by LC-UV and 100-1000 ng mL(-1) by LC-MS. Mass spectrometry coupled with electrospray ionization interface is described for the identification of shikimic acid in various plant samples. This method involved the use of the [M-H](-) ions of shikimic acid at m/z 173.0455 (calculated mass) in the negative ion mode with extractive ion monitoring.