甜菊糖苷类化合物的质谱行为分析及定量策略初探

LC-MS Analysis of Steviol Glycosides and Preliminary Study on Quantitative Strategy for Steviol Glycosides in Stevia Leaves

混合体系多组分定量是现代分析科学研究难点,探讨建立利用液质联用(LC-MS)对作物器官所含各化合物进行定量的化学计量方法是化学形态学研究的基础,有利于作物品质育种亲本选配及栽培管理措施评价。本研究以甜叶菊叶片所含12种主要甜菊糖苷类化合物为例,通过考察归属各甜菊糖苷化合物的质荷比≥M/2的初级和次级裂解离子、分子离子、加和离子、双分子及三分子聚合物离子等各组分及其同位素化合物离子的定量检出信息稳定性及各检出峰面积与化合物浓度梯度之间的相关性,探讨利用LC-MS方法对混合体系——甜菊叶提取液中各甜菊糖苷组分进行定量的策略。结果表明,LC-MS对归属同一甜菊糖苷化合物的各组分及其同位素化合物的检出受混合体系中甜菊糖苷化合物的浓度影响大,检出峰面积相对占比因甜菊糖苷浓度不同呈不规则波动,以归属同一化合物的各组分及其同位素化合物检出峰面积总和为依据所建立的LC-MS定量体系更适用于化合物浓度差异大的混合体系。

Quantification of multi-components in mixed systems is a challenge for analytical research,establishment of a LC-MS strategy for quantify of compounds contained in crop organs is basis of plant chemical morphology research,which is conducive to select parents for crop quality breeding and evaluation management measures for cultivation.In this study,12 main steviol glycosides in stevia leaves were taken as examples,primary and secondary fragmentation ions,molecular ions,additive ions,bi-and tri-molecular ions,isotopic compounds of above components were investigated as well.Correlation between quantitative detectable information of each component and concentration gradient of steviol glycoside were employed to explore LC-MS quantification strategy for each steviol glycoside in mixed system of stevia leaves.Results showed that detectability of each component and the isotopic ones of steviol glycosides by LC-MS is greatly affected by concentration of compound in mixed system,LC-MS quantitative system established based on sum of quantitative detectable peak areas of components and their isotopic compounds is suitable for mixed systems with compounds of largely differences in concentration.