UV Spectrophotometric Measurement of Total Flavonoids in Citrus Peels

Total flavonoid in citrus peels was determined by UV spectrophotometry at 271 nm using rutin as the standard compound.The calibration curve was linear in the range of 6.2 μg/mL-56 μg/mL for rutin(r=0.999 3).The extraction conditions of total flavonoid from citrus peels were compared by ultrasonic and microwave assistance with the uniform design method,with respects of power,extracting time,ethanol concentration,ratio of solid to liquid as the investigated factors,and it was found that the microwave extraction rate was higher than ultrasound-assisted extraction rate in the tested experimental conditions.The chosen extraction condition of microwave method was as follows: microwave power 60 %,extracting time 7 minutes,50 % ethanol,and ratio of solid to liquid 1∶45(g/mL).Therefore,microwave method was selected as the extraction method of total flavonoid measurement by UV spectrometry in citrus peels.The average recovery of the methods was 99.5 %,and the method was satisfactorily used in determination of total flavonoids in citrus peels.