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Ultrasound-assisted extraction of ginsenosides from ginseng in supercritical CO 2 reverse microemulsions formed by bis(2-ethylhexyl) sodium sulfosuccinate (AOT) was studied. Prior to extraction the ginseng was soaked in water for 12 h. It was found that ultrasound significantly enhanced supercritical CO 2 reverse microemulsion extraction. The ginsenoside extraction yield from supercritical CO 2 reverse microemulsion with ultrasound of 20 kHz, 15.2 W cm −2 and 3/6 s was 2.63 times that without ultrasound at 24 MPa extraction pressure, 45 • C extraction temperature, 4 h extraction time, 5 MPa separation pressure, 55 • C separation temperature and 2 L h −1 CO 2 flow rate with 140 mL of 0.07 mol L −1 AOT/ethanol. The maximum extraction yields of ginsenosides from different concentrations of reverse microemulsions were obtained at different ultrasonic intensities. The extraction yield with 20 kHz ultrasound was higher than that with 38 kHz ultrasound at suitably low intensity; however, it was lower at high intensity. The yield improvement may be basically attributed to the mechanical and thermal effects of ultrasound.

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Methamidophos (MDP) and dichlorvos (DDVP) are organophosphorous pesticides which are commonly used for pest control in agriculture to obtain better yields.

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