Abstract: Extraction of chlorophyll from Forsythia suspensa leaves using cloud point extraction coupled with ultrasonication was investigated in the present study.Single factor test and orthogonal design were used to determine the optimal conditions with absorbance values of 665 nm as the index of evaluation.The optimal conditions for the extraction of chlorophyll were as follows:Triton X-114 concentration of 4%,ultrasonic power of 250 W,ultrasonic time of 11 min,and solid-liquid ratio of 1:10.Comparing the developed extraction method with the traditional organic solvent extraction methods and ultrasonic extraction method,the extraction rate improved 9.92% and 11.58%,respectively.This study provided a new method for the extraction of chlorophyll with the following advantages:low temperature (room temperature) of extraction,no using volatile or toxic organic solvents,economical,safe,efficient,convenient,time-saving,environmental protection,etc.In addition,the method can be applied for the extraction of chlorophyll from other natural resources.

Key words: Forsythia suspensa leaves, cloud point extraction, ultrasonic extraction, chlorophyll, UV-VIS spectrophotometry