Extraction-Photometric Determination of Total Alkaloids in Camptotheca Acuminata with Methyl Orange as Color Reagent

For determination of total alkaloids in camptotheca acuminata,100 μL of the extract of sample was reacted with methyl orange in a citrate-phosphate buffer medium of pH 5.The reaction mixture was kept at 25 ℃ for 5 min,and extracted with 10 mL of chloroform to transfer alkaloids into the organic phase,the absorbance of which was measured photometrically at 366 nm against chloroform as reference solution.Camptothecin was used as reference material in the determination.Linear relationship between values of absorbance and concentration of captothecin was obtained in the range of 6.5-104.0 mg·L-1.Precision was tested by analyzing 5 portions of samples from the same batch for their total alkaloid contents with the proposed method,value of RSD found was 1.62%.On the base of a known sample,test for recovery was made by standard addition method,value of average recovery obtained was 98.7%.