On-line conversion and determination of artemisinin and its kinetic parameters using orthogonal design by coupling of flow injection with capillary electrophoresis Original Research Article

A rapid, accurate and improved capillary electrophoresis (CE) coupled with flow injection (FI) method with 6.5 cm long separation capillary for the determination of artemisinin and its relevant kinetic parameters by on-line treatment with alkali has been developed. Orthogonal experimental design has been utilized to optimize experimental factors that affect the analysis of artemisinin. The buffer pH value (pH), the concentration of the buffer (image), the applied voltage (Va), the concentration of alkali (CNaOH), the heating time (th) and the reaction temperature (Tr) are selected as the investigating variables. The different effects on the peak area are studied by the orthogonal design method. As a result, the optimum experimental factors are 10.5 for pH, 10 mmol/L for image, 2.1 kV for Va, 0.4 mol/L for CNaOH, 2 min for th, and 40 °C for Tr. Analysis is carried out in less than 2 min after conversion of artemisinin in the FI system that is coupled to CE equipment via a split–flow interface cell. The method has been used to determine not only the content of artemisinin in medicine plant Artemisia annua L., but also the activation energy and the chemical respond order of the conversion from artemisinin to Q292.