玉米种子中4种可溶性糖含量UPLC-ELSD测定方法的优化及其应用

Simultaneous Separation and Determination of Fructose,Glucose,Sucrose and Maltose in Maize Seed by UPLC-ELSD

对比了HPLC-RID法和UPLC-ELSD法对果糖、葡萄糖、蔗糖和麦芽糖4种可溶性糖的检测。结果表明:UPLC-ELSD法的分离效果、重复性、灵敏度等比HPLC-RID法好,确定了UPLC-ELSD法测定4种糖含量的技术参数,即流动相为0.2%(w/v)三乙胺溶于75%(v/v)乙腈,流速为0.2 m L/min,柱温为35℃,上样量为2μL,在6 min内可以灵敏、快速地检测出果糖等4种可溶性糖。利用UPLC-ELSD法测定玉米种子吸胀过程中蔗糖、麦芽糖、葡萄糖和果糖4种可溶性糖的含量,结果表明:胚乳在吸胀之前,仅检出蔗糖、葡萄糖和果糖,其中蔗糖含量最高,随着种子吸胀,蔗糖含量先下降后上升,而葡萄糖和果糖逐渐增加,吸胀48 h时检出麦芽糖。胚在吸胀之前,4种可溶性糖均可以检测到,且含量均显著高于胚乳,在吸胀过程中4种糖的变化规律与胚乳相似。因此,在玉米种子吸胀过程中,可能先动员蔗糖分解成葡萄糖和果糖,再动员贮藏物质合成蔗糖、麦芽糖、葡萄糖和果糖,为种子萌发生长提供能量和中间物质。

UPLC-ELSD was carried out to simultaneous determination of fructose,glucose,sucrose and maltose in maize seed. UPLC-ELSD was utilized with a mobile phase with 75%（ v / v） acetonitrile containing 0. 2%（ w / v）triethylamine. In addition,the flow rate of mobile phase was 0. 2 m L / min and the column temperature was set to35 ℃. The proposed UPLC-ELSD method was validated for quantification of fructose,glucose,sucrose and maltose in maize endosperm and embryo during imbibition. The results showed that the content of four sugars various in both organs. In endosperm,the content of sucrose reached a minimum at 48 h imbibitions. The contents of fructose and glucose showed similar,displaying a steady rise during imbibition. However,maltose could be detected in 48 h. In dry embryos,the contents of four sugars could be detected and more than in endosperm. During imbibition,the contents of sugars in embryos showed very similar profiles to in endosperms. Taken together,these results might suggest that sucrose degraded to glucose and fructose in the beginning of imbibitions. Prolong with imbibition,reserve substance degraded into sucrose,maltose,glucose and fructose,providing carbon source for the maize seed germination.