Application Research Of Capillary Electrophoresis In Separation And Analysis Of Camptothecin Alkaloids

Objective: This paper reported the Sulfobutylether-?-Cyclodextrin(SBE-?-CD)and ionic liquid(IL)were used as electrolyte additives for the separation and determination of camptothecin alkaloids by capillary electrophoresis,and studied the application of large volume sample stacking(LVSS)on the analysis of camptothecin alkaloids by capillary electrophoresis.In addition,capillary electrophoresis separation and determination method was established,which is simple,fast,effective,and can save the organic solvent;also could be applied for the separation and quantification of camptotheca fruit,camptotheca bark and camptotheca ointment.Methods:(1)A capillary electrophoresis method was developed using SBE-?-CD and IL as electrolyte additives for the separation and determination of camptotheca fruit and camptotheca ointment.Separation parameters such as buffer concentration,p H,the concentration of SBE-?-CD and IL,separation voltage were all investigated to obtain the optimum separation and determination conditions.The experiment was carried out on an uncoated fused silica capillary(50 cm×75 ?m,effective length 40 cm),and the optimum separation results was obtained with the buffer composed as following: 20 m M borate solution,20 m M SBE-?-CD,100 m M IL,p H 9.0,the separation voltage was 20 k V,the injection: 0.5 psi pressure for 5.0 s,the detection wavelength was 254 nm.(2)A large volume sample stacking-capillary electrophoresis method was established for the quantification of trace camptothecin alkaloids,and the method with SBE-?-CD accompanied IL used as the background electrolyte additives was used for the separation and analysis of camptothecin alkaloids in camptotheca fruit and bark.Separation parameters such as buffer concentration,p H,concentration of SBE-?-CD and IL,separation voltage,stacking condition were all tested to obtain the best separation and concentration conditions.The experiment was carried out on a fused silica capillary(50 cm×75 ?m,effective length 40 cm),and the best separation results were achieved with the background electrolyte composed as following: p H 9.0,25 m M borate solution,20 m M SBE-?-CD,20 m M IL,separation voltage 20 k V,the detection wavelength 254 nm.The best stacking results were obtained with conditions as following: reverse voltage-25 k V,the polarity switching time 0.17 min,injection condition:0.5 psi for 4.0 s.Results:(1)Under the optimum capillary conditions,the four camptothecin alkaloids could be separated within 10 min;the intraday RSD <4.6%,the interday RSD <7.6%;the linearity was evaluated with the concentration ranged from 10 to 100 ?g/ml for the four analytes with the correlation coefficients from 0.9946~0.9985;the average recovery of real samples ranged from 98.8%~103.6%.(2)Under the optimum capillary conditions,the five camptothecin alkaloids could be separated within 20 min;the intraday RSD <1.23% and the interday RSD <3.70%;the linearity was evaluated with the concentration ranges from 10 to 500 ?g/ml for the five analytes with the correlation codfficients from 0.9991~0.9997;the average recovery of real samples ranged from 95.0%~103.2%;Under the optimum large volume sample stacking-capillary electrophoresis conditions,the analytes could be stacked successfully and the concentration fold of five analytes were from 5 to 13.Conclusion: Ionic liquid can be combined with ?-CD as the background electrolyte additive in capillary electrophoresis for the separation and quantification of camptothecin alkaloids.The on-line concentration method of large volume sample stacking can be applied for the analysis of trace camptothecin alkaloids in camptotheca fruit and bark.The proposed method can be used for the analysis of camptothecin alkaloids in real samples,and the IL,as the separation selectors in background electrolyte,can be applied to the separation and determination of camptothecin alkaloids by capillary electrophoresis.