Abstract
An efficient pressurized capillary electrochromatography (pCEC) method has been successfully developed for the determination of six catechins in tea. The separation was performed on a reversed-phase EP-100-20/45-3-C18 capillary column (total length of 45 cm, effective length of 20 cm, diameter of 100 μm, ODS packing inside for 3 μm). The mobile phase ratio of organic phase, the concentration of phosphate buffer and sodium heptanesulfonate, separation voltage, and other experimental conditions were investigated and optimized. The mobile phase was 15 mM NaH2PO4 and 12 mM sodium heptanesulfonate (pH 3.0)/methanol (64:36) at a flow rate of 0.04 mL/min. Under optimal conditions including applied voltage of −4 kV and a UV detection wavelength of 230 nm, the six catechins in the tea were well separated. The calibration curves for the analytes had good linearity in the range of 8.02 μg/mL–202.13 μg/mL with a correlation coefficient of 0.9928–0.9997. The limits of detection (LOD) for the six catechins were 4.62 μg/mL–11.63 μg/mL (S/N = 3). The recoveries of the six catechins were 96.2%–108.4% with a relative standard deviation (RSD) between 0.78% and 4.51%. The method has been used for the determination of six catechins in tea samples with good results.
GRAPHICAL ABSTRACT
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Disclosure statement
All authors declare no conflict of interest.