用超临界CO_2络合萃取法脱除中成药中的重金属

研究影响超临界 CO2 络合萃取中成药中重金属的主要因素。以二乙基二硫代氨基甲酸二乙铵 (Et2 NH2 DDC)为络合剂 ,研究了压力、温度、携带剂 (乙醇 )用量和萃取时间等因素的影响。结果表明 ,对 Pb,As,Cu的萃取存在最适宜萃取温度且各不相同 ,其最适宜萃取温度依次升高 ;而汞的去除率随温度升高而下降。压力升高和携带剂用量增加使铜的去除率增加 ,但对 As,Hg,Pb的去除影响不明显。除 Pb外 ,As,Hg,Cu的去除率随萃取时间的延长而升高。因此 ,主要因素是萃取时间和适宜的萃取温度 ,压力和携带剂用量的增加有利于加快对微量重金属的萃取速度。该研究可为去除中成药中痕量重金属提供最佳工艺条件。

Removal of heavy metals from a Chinese traditional medicine by supercritical CO_2 chelating extraction

This paper investigates the effects of pressure, temperature and a modifier (ethanol) on CO 2 supercritical chelating extraction of heavy metal ions from a Chinese traditional medicine. The results indicate that the optimal temperatures for extraction efficiency differ for the same conditions and increase in the order of Pb, As, and Cu, while the extraction efficiency for Hg decreases as the temperature increases. Increasing the extraction pressure or the modifier concentration in the supercritical CO 2, the extraction efficiencies for As, Pb, and Hg do not increase noticeably, while the extraction efficiency for Cu increased markedly. The extraction efficiencies for As, Hg, Cu increase with the extraction time but not for Pb.