Determination of limonoids in citrus fruits

A spectrophotometric method for the determination of limonoids in the extract of citrus fruits was established.Research showed that the limonoids reacts with Ehrlich's reagent to form a stable red complex,its maximum absorption wavelength is 490 nm.Taking the limonin as the standard to get the regression equation is A=0.888 9C+0.096 6,and the correlation coefficient R2 is 0.999 7.The absorbance was linear with concentration of the limonoids in the range of 0.015 0～0.187 5 mg/mL.The average recovery is 100.12%,RSD=1.78%(n=6).