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An HPLC-UV-MS method for simultaneous identification of predominant phenolics and minor nucleoside derivatives in<i> Gastrodia elata</i> was developed, which was based on their UV and MS characteristics summarized through a series of homemade reference standard experiments. Phenolics showed characteristic UV λ<sub>max</sub> at 267 nm, [M + NH₄]⁺ base peak in positive mode and [M-H]⁻ base peak in negative mode while nucleosides exhibited UV λ<sub>max</sub> at 255 nm, [M + H]⁺, [M-H + 2H₂O]⁻ or [M-H + CH₃COOH]⁻. Phenolics conjugates mainly underwent the consecutive loss of gastrodin residue (-268 U) and the combined loss of H₂O and CO<sub>2 </sub>from the citric acid unit under negative MS/MS conditions whereas nucleosides simply lost the ribose (-132 U) under positive MS/MS conditions. According to these characteristics, a special pattern under MS/MS conditions and reported compound data for<i> G. elata</i> in the literature, not only 15 phenolics were identified but also 6 nucleoside derivatives were identified. Among these compounds, seven phenolics and three nucleoside derivatives have not been reported yet from<i> G. elata</i>.

<br>Display Omitted<br>• The effect of organic sample solvents in SCX mode were systematically studied. • Organic sample solvents affect the separation efficiency in SCX mode seriously. • Elution strength of organic solvents affect efficiency of later-eluted analyte. • Retention of organic solvents affected efficiency of earlier-eluted analyte. • The results can be used for the optimization of SCX methods.<br>This study investigated the influence of organic sample solvents on separation efficiency of basic compounds under strong cation exchange (SCX) mode. The mixtures of acidic aqueous solution and organic solvent such as acetonitrile, ethanol, methanol and dimethyl sulfoxide (DMSO) were tested as sample solvents. For later-eluting analytes, the increase of sample solvent elution strength was responsible for the decrease of separation efficiency. Thus, sample solvents with weak elution strength could provide high separation efficiencies. For earlier-eluting analytes, the retention of organic sample solvents was the main factor affecting separation efficiency. Weakly retained solvents could provide high separation efficiency. In addition, an optimized approach was proposed to reduce the effect of organic sample solvent, in which low ionic solvent was employed as initial mobile phase in the gradient. At last, the analysis of impurities in hydrophobic drug berberine was performed. The results showed that using acidic aqueous methanol as sample solvents could provide high separation efficiency and good resolution (<b>R</b> > 1.5).

A new xanthone glycoside ( 1 ) has been isolated from Swertia franchetiana together with five known xanthone glycosides. Their structures were elucidated as 7- O -[&beta;- d -xylopyranosyl-(1&rarr;2)-&beta;- d -xylopyranosyl]-1,7,8-trihydroxy-3-methoxyxanthone ( 1 ), 7- O -[&alpha;- l -rhamnopyranosyl-(1&rarr;2)-&beta;- d -xylopyranosyl]-1,7,8-trihydroxy-3-methoxyxanthone ( 2 ), 8- O- &beta;- d -glucopyranosyl-1,3,5,8-tetrahydroxyxanthone ( 3 ), 1- O- &beta;- d -glucopyranosyl-1-hydroxy-3,7,8-trimethoxyxanthone ( 4 ), 1- O -[&beta;- d -xylopyranosyl-(1&rarr;6)-&beta;- d -glucopyranosyl]-1-hydroxy-2,3,5-trimethoxyxanthone ( 5 ) and 1- O -[&beta;- d -xylopyranosyl-(1&rarr;6)-&beta;- d -glucopyranosyl]-1-hydroxy-3,5-dimethoxyxanthone ( 6 ) on the basis of spectroscopic evidence.

Two new iridoid glycosides designated as senburiside III (2) and senburiside IV (3), together with one known iridoid glycoside senburiside I (1) and three known secoiridoid glucosides swertiamarin (4), gentiopicroside (5) and sweroside (6), were isolated from the whole plant of Swertia franchetiana. The structures of the two new compounds were elucidated by spectroscopic methods.;