Efficient removal of the organochlorine pesticide and heavy-metal residues inEpimedium brevicornum Maxim by supercritical fluid extraction

Abstract

A method involving depuration of 12 organochlorine pesticides (OCPs) and 7 heavy metals from Epimedium brevicomum Maxim was developed using supercritical fluid extraction (SPE). The pesticides in the study consisted of alpha, beta-, gamma-, and delta-Benzene hexachloride, Pentachloronitrobenzene (PCNB), Pentachloroaniline (PCA), Heptachlor (HEPT), Methyl -pentachlorophenyl sulfide (MPCPS), pp'-DDE[1,1-dichloro-2, 2-bis (p-chlorophenyl) ethylene], op'-DDT [1,1,1-trichloro-2-(o-chlorophenyl)-2-(p-chlorophenyl)ethane], pp'-DDD [1,1-dichloro-2-2-bis(p-chlorophenyl)]ethane, pp'-DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane]. A series of experiments was conducted to optimize the final extraction conditions as following: pure CO2, extraction pressure of 15 Mpa, extration temperature of 60 degrees C, extraction time of 10 min, flow rate at 55 kg/h. A GC method with electron capture detection was employed to determination of the OCPs, and an atomic absorption spectrometry (AAS) was designed for the determination of 7 heavy metals including of Pb, Cd, Cu, Fe, Zn, As, Hg in Epimedium brevicomum Maxim. A HPLC method was developed for the quantitative determination of active constituents. The SFE was used to remove the organochlorine pesticide and heavy metals from Epimedium brevicornum Maxim, receiving high decontamination rate of pesticide residue and low loss of active constituents.