Nano Channel Separation Bisphenol A Small Molecules Such As Environmental Pollutants

Nanochannel is the pores or tubules with diameter from0.1to100nanometers. Nanochannels play a significant role in the separation oflife sciences, biological materials, small organic molecules and chiralsubstances due to the size effect, highly specific surface area, specialnano-structure physical characteristics and convenient modification.Some small organic molecules such as Rhodamine B anddiphenylamine can cause cancer, teratogenesis risk. They are veryharmful to human health. Bisphenol A (BPA) and dibutyl phthalate (DBP)are environment estrogen (ECDs), their molecular structure are similar tonormal vivo estrogen. They destroy reproduction, growth and otherphysiological activities of human. Usually, both are often separated anddetected by gas chromatography-mass spectrometry, highperformance liquid chromatography, liquid chromatography-massspectrometry andsupercritical fluid chromatography. Compared withthese methods, nanochannel technology is more effective and hasbetter performance. This paper is mainly centered on the preparationprocess of gold nanochannels, the separation of estrogens and smallorganic molecules by functional gold nanochannels technique. Themodification of L-cystiene onto the nanochannel was characterized byElectrochemical Impedance Spectroscopy. Details are presented in thisthesis as follows:（1） Au was successfully deposited within the pores of thepolycarbonate template membrane using electroless depositionmethod and the experiment conditions was greatly improved thanthose used before. Field emission scanning electron microscope,transmission electron microscope were used to characterize the poresize and the surface appearance. The different hydrophobicnanotubules can be obtained by self-assembling octadecylthiol (HSC18H37),1-dodecanethiol (HSC12H25) or1-heptanethiol (HSC7H15)onto the gold nanochannels. It can be used to separate Rhodamine Band diphenylamin by the hydrophobic gold-nanotubules membranes.Rhodamine B and diphenylamin can be completely separated basedon nanotubules modified with octadecylthiol membrane, becausethose two compounds have different hydrophobicity. The resolution ofnanotubules membranes modified with1-dodecanethiol (HSC12H25)and1-heptanethiol (HSC7H15) for the separation of Rhodamine B anddiphenylamin were36.63and1.691, respectively.（2）L-cysteine with a unique chemical structure, is often used as agold-nanochannel modifier. However, there are few reports on thestudy of adsorption characteristics of L-cysteine onto thegold-nanotubules. The gold membrane modified with L-cysteine wasfixed on glassy carbon electrode (GCE) by an O-ring. Anelectrochemical cell contain three electrodes using this GCE fixed withmembrane modified with L-cysteine as working electrode. Theadsorption of L-cysteine onto the nanotubules can be characterized byelectrochemical impedance spectroscopy （EIS）. The effects ofadsorption time and concentration of L-cysteine by EIS wasinvestigated. It has provided a new method to study the L-cysteineadsorbed onto nanochannel.（3） L-cysteine was modified into the pores of the goldnanochannel by self-assembly. This surface charge of the nanotubulesmodified by L-cysteine can be changed in response to the pH value ofthe solution. When the pH of solution is lower than pI, the surface of thenanopores are charged positively due to the protonation of L-cysteine.DBP negative charged can transports through this membrane and theneutral BPA is difficult to pass this nanotubules resulting in separation ofthose two compounds. The resolution of DBP and BPA can be increasedfrom1.494to2.466. A method of DBP and BPA was established based on the different charges between BPA and DBP.In summary, we developed some new approaches to separateenvironment estrogen and other small organic molecular bynanochannels in combination with conventional detection methods.We can expect to provide some theoretical support for more widelypractical application of nanochannels.