Studies On The Extraction Technology Of Avermectin B_1a

The content of avermectin B_1a in extractor was determined by HPLC. Active components showed good linear relationship in the range of 24-240mg·L^-1 (r=0.9999). The methods can be used for the quality control.By using the content of avermectin B_1a as quality control criteria, The effects of medium, ratio material to liquid, power, time frequency and extraction time on the extractive results of avermectin B_1a were explored at the same time. The optimum ultrasonic extraction conditions were as follows: 95% ethanol, 1: 5 (w/v) ,the Ratio material to liquid; 400W, the supersonic power; 20 min, the supersonic time. Repetition operation and the yield of avermectin B_1a was 95.22%. The extractor of ultrasonic extraction in circulation was only 20min and the yield of avermectin B_1a was 96.22%.By using the content of avermectin B_1a as quality control criteria, The effects of pressure, temperature, extraction time, the flow rate of CO₂, and separate temperature on the extractive results of avermectin B_1a were explored at the same time, the curves of the influence factors were drawn. The SFE- CO₂ conditions for avermectin B_1a were as followed: pressure 30MPa, temperature 45℃, the CO₂ volumetric rate 6.4L/h, extraction time 1.5h, the sepatate pressure 5 MPa, the separate temperature 40℃. The result showed that the avermectin B_1a extractive yield was 97.21%.Compared with the technology of SFE-CO₂, ultrasonic extraction and the solubilities in ethanol. The result showed that the SFE-CO₂ of avermectin B_1a was simple and efficient. The produce cost of SFE was lower and the crystallization craft was simple, the crystall purity was 92.21%. The ultrasonic extraction time was shorter, but the crystallization craft was complex. The solubilities in ethanol of extraction time was longer and the crystallization craft was complex.