加压毛细管电色谱测定甘蔗中三种多酚类化合物

为建立加压毛细管电色谱(pCEC)分离检测甘蔗中多酚类化合物绿原酸、阿魏酸、表儿茶素的方法,采用C₁₈毛细管色谱柱,以NaH₂PO₄和甲醇为流动相,优化了流动相比例、缓冲盐pH、缓冲盐浓度、分离电压、流速等色谱条件。结果表明,在流动相为15.0 mmol/L NaH₂PO₄+12.5 mmol/L庚烷磺酸钠(pH5.0)/甲醇(50:50,V/V)、分离电压为1 kV、流动相总流速为0.06 mL/min、检测波长为220 nm的色谱条件下,绿原酸、阿魏酸、表儿茶素分离较好,在20~320 μg/mL线性关系良好,相关系数分别为0.9978、0.9922、0.9971,检出限分别为0.14、0.75、1.65 μg/mL,相对标准偏差分别为2.82%、2.69%、1.18%,平均回收率分别为96.79%、100.71%、99.01%。该方法快速、准确、重复性好,适用于甘蔗中多酚类化合物的分离检测。

Determination of Three Polyphenols in Sugarcane by Pressurized Capillary Electrochromatography

The method for the separation and detection of chlorogenic acid,ferulic acid and epicatechin in sugarcane was established by pressurized capillary electrochromatography( pCEC).C18 capillary column with sodium dihydrogen phosphate and methanol as mobile phase were used to optimize the flow ratios,buffer salt p H,buffer salt concentration,separation voltage,flow rate and other chromatographic conditions.The results showed that mobile phase was 15.0 mmol/L NaH2 PO4 and 12.5 mmol/L sodium heptanesulfonate( pH5.0)/methanol( 50∶ 50,V/V) at a flow rate of 0.06 m L/min. Under optimal conditions including applied voltage of 1 kV and a UV detection wavelength of 220 nm,chlorogenic acid,ferulic acid and epicatechin in sugarcane were well separated. The calibration curves for the analytes had good linearity in the range of 20 ~ 320 μg/m L with the correlation coefficients as 0.9978,0.9922 and 0.9971.The limits of detection( LOD) for the chlorogenic acid,ferulic acid and epicatechin were 0.14,0.75,and 1.65 μg/m L. The recoveries were 96.79%,100.71% and 99.01% with a relative standard deviation( RSD) were 2.82%,2.69% and 1.18%,respectively. The results showed that the method was fast,accurate and reproducible,and suitable for the separation and detection of polyphenols in sugarcane.