Studies On The Extraction Of Nicotine By Modified Membrane

Liquid membrane separation technique is a novel membrane separation method whichhas developed in the mid1960s.With this technique, the target compounds can be extractedfrom complex bio-matrix.Because it offers the advantages of good selectivity, high separationefficiency,low energy consumable,high enriching timesand, easy operating,etc. Since itsadvent,it was widely applied to many fields such as hydrometallurgy, chemical analysis,swage treatment, petrochemical engineering and biomedicine.In the first part of this paper, supported liquid membrane(SLM) extraction technique wasemployed for analyzing nicotine using hog casing as membrane support material.Theinfluencing factors such as the thickness of the membrane material, extraction time, theconcentration of the donor, the diffusion coefficient of analyte and the mass transfer resistanceof membrane were investigated.The result shows that extraction efficiency is mainlydetermined by the diffusion coefficient of nicotine in the organic liquid,and relevant to theconcentration and the diffusion coefficient of nicotine in the donor. The extraction of nicotineincreases rapidly with the increase of extraction time. When extraction yields reach a certainquantity, the amount of transfer nicotine tends to saturate. The concentration of nicotine is themost in the extract of tobacco, so the relative extraction yields get to92%. And the othernicotine which are low content can aslo be extracted such as nornicotine, neonicotine andanatabine, their relative extraction yields are about8%.In the second part, emulsion liquid membrane(ELM) extraction technique was employedfor analyzing nicotine using W/O/W system. The experiment used kerosene as organic phase,Span80as surfactant, sulphuric acid solution as internal phase and polystyrene and butadienerubber as polymeric additive. The influencing factors such as the pH of the acceptor andextraction time were investigated. And then, ELM was employed for analyzing nicotine oflocal tobacco. The influencing factors such as extraction time, the pH of the donor, the typeand the addition of polymers, membrane added extractant and the addition of surfactant werediscussed. The result shows that the W/O/W system which uses kerosene with polymersadded as organic phase can control the volume of the donor before and after extractionremaining constant efficiency, extend the outer alkaline inner acidity situation of extractionsystem and improve stability of extraction system. And its extraction efficiency is superior tothe system of pure kerosene. The emulsion with butadiene rubber added has much better effect than emulsion with polystyrene added either stability or extraction yields. Butextraction yields dosen’t varies directly with the addition of butadiene rubber. The factorssuch as the stability of emulsion, the pH of the internal phase and the pH of the external phasecan affect extraction efficiency. And extraction yields of the W/O/W extraction system whichuses kerosene with butadiene rubber added as organic phase is1.5times of liquid-liquidextraction.