Abstract
A sensitive, effective and optimized method, based on ultra performance liquid chromatography (UPLC) coupled with ESI-triple quadrupole ion MS and ESI-linear ion trap high-resolution MS, has been developed for the simultaneous quantitative and qualitative determination of phenolics, nucleosides and amino acids in the roots of fresh Gastrodia elata. Optimization of the analytical method provided higher separation efficiency and better peak resolution for the targeted compounds. The simultaneous separation protocols were also optimized by routinely using accurate mass measurements, within 5 ppm error, for each molecular ion and the subsequent fragment ions. In total, 31 compounds, including 23 phenolics, two nucleosides, four amino acids, one gastrodin and one other compound were identified or tentatively characterized. Mono-substituted parishin glucoside (9), methoxy mono-substituted parishin (13), methyl parishin (26), p-hydroxybenzyl di-substituted parishin (29), and p-hydroxybenzyl parishin (31) were tentatively identified as new compounds. Principal metabolite content analysis and the composition of eight representative G. elata cultivars of various species indicated that geographic insulation was the main contributor to clustering.