场放大进样-扫集胶束电动色谱法测定金银花中的咖啡酸与绿原酸

Determination of Caffeic Acid and Chlorogenic Acid in Honeysuckle by Field-amplified Sample Injection and Sweepingmicellar Electrokinetic Chromatography

以场放大进样-扫集胶束电动色谱法(FASI-sweeping-MEKC)测定了金银花中的咖啡酸、绿原酸。考察了SDS浓度、进样电压、进水时间与进样时间比值、进样时间以及缓冲液组成对分离效果的影响。最佳分离条件为:采用未涂层熔融石英毛细管(50 cm×50μm,有效柱长33 cm),缓冲体系为100 mmol/L十二烷基磺酸钠(SDS)+20 mmol/L NaH2PO4(pH 2.2)+15%乙腈,环境温度25℃,分离电压-20 kV,进样电压-10 kV,进样时间15 s,进水时间195 s(H=20.0 cm),测量波长215 nm。在优化条件下,两种有机酸均在15 min内出峰,峰面积的相对标准偏差(RSD)均小于4%。咖啡酸和绿原酸的线性范围分别为29.4～470.4、48.5～776μg/L,检出限(S/N=3)分别为1.12、2.18μg/L,加标回收率分别为98%～106%和96%～106%。

Field-amplified sample injection and sweeping-micellar electrokinetic chromatography（FASI-sweeping-MEKC） was used in the simultaneous separation and determination of caffeic acid and chlorogenic acid in honeysuckle.Effects of experimental conditions,such as concentration of SDS,injection voltage,injection time ratio of water to sample,injection time,composition and concentration of background electrolyte on separation efficiency were optimized.The optimal conditions were as follows：separation column：an uncoated fused silica capillary column（50 cm×50 μm,effective length 33 cm）,background electrolyte：100 mmol/L sodium dodecyl sulfate（SDS）-20 mmol/L NaH2PO4（pH 2.2）-15% acetonitrile,temperature：25 ℃,detection wavelength：215 nm,sample injection voltage：-10 kV,separation voltage：-20 kV,sample injection time：15 s,water injection time：195 s（H=20.0 cm）.Under the optimum conditions,the separation of the two organic acids was performed for 15 min with RSDs of peak area less than 4%.The calibration curves showed good linearities in the ranges of 29.4-470.4 μg/L for caffeic acid and 48.5-776 μg/L for chlorogenic acid with detection limits（S/N=3）of 1.12 μg/L and 2.18 μg/L,respectively.The spiked recoveries were in the range of 98%-106% and 96%-106%,respectively.