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  本文關(guān)鍵詞： 表面增強拉曼光譜技術(shù)（SERS） Au溶膠 磁性核殼材料 硝基呋喃類抗生素　出處：《江南大學(xué)》2013年碩士論文　論文類型：學(xué)位論文

【摘要】：硝基呋喃類抗生素是一類廣譜性抗菌藥，包括呋喃唑酮（N1）、呋喃妥因（N2）、呋喃西林（N3）、呋喃它酮（N4），曾作為添加劑廣泛應(yīng)用于飼料及獸藥之中，由于已被證實對動物體具有潛在的毒性、誘變性及致癌性，近年來已被各國陸續(xù)禁止使用。然而其價格低廉而藥效明顯，違禁使用硝基呋喃類抗生素的情況仍然不斷曝光。表面增強拉曼光譜（SERS）是以拉曼光譜為基礎(chǔ)，借助納米材料表面的特殊光學(xué)性質(zhì)，而獲得物質(zhì)分子指紋信息的一種技術(shù)；因其快速、無損、低耗、精確等優(yōu)點，近年來在各科研領(lǐng)域發(fā)展迅速。本研究擬借助SERS技術(shù)，輔助納米材料合成與修飾技術(shù)建立一種快速檢測硝基呋喃類抗生素的方法。 首先，通過密度泛函理論計算，對硝基呋喃類抗生素的特征拉曼振動進行理論分析，以為其定性提供理論依據(jù)。確定其拉曼特征振動主要為1602cm~(-1)處的C=N面內(nèi)對稱伸縮振動；1556cm~(-1)的NO_2非對稱伸縮振動、呋喃環(huán)的對稱伸縮振動；1484cm~(-1)處的呋喃環(huán)面內(nèi)對稱伸縮振動；1336cm~(-1)處的H-C-H對稱伸縮振動、呋喃環(huán)搖擺振動；1220cm~(-1)處的C-N-N對稱伸縮振動。 其次，制備經(jīng)典Au溶膠、磁性核殼納米材料，對其形貌及檢測條件進行分析，通過比較SERS增強效果確立最佳實驗條件。一，在以Au溶膠為SERS活性基底時，應(yīng)以丙酮為溶劑，待測樣品與基底體積比為1:2，將體系pH值調(diào)至3.0~4.0之間，N1、N2、N4的最低檢測限可達到5ppm，但N3無法檢出，原因在于N3分子結(jié)構(gòu)式的特殊性使其拉曼活性基團難以與Au溶膠表面充分接觸。二，在以磁性核殼材料為基底時，應(yīng)以Fe_3O_4@Ag為基底，Ag殼層厚度為40nm左右，基底在檢測體系中的濃度為0.5g/ml，以633nm為激發(fā)波長，四種物質(zhì)的最低檢測限可達到0.1ppm。同時，通過分子組裝技術(shù)在Fe_3O_4@Ag表面修飾了L-半胱氨酸，結(jié)果顯示N3在該基底上可以獲得更好的SERS效果。三，，從定性準(zhǔn)確度、檢測限、重現(xiàn)性等方面對上述兩種基底的SERS效果進行了對比，總結(jié)認(rèn)為基底Fe_3O_4@Ag的SERS效應(yīng)最佳，因為Fe_3O_4@Ag的形貌、分布、間距更為規(guī)則均一，有利于激發(fā)SERS效應(yīng)，且其Ag殼層表面的粗糙度更高，具有更大的表面積從而可以提供更多SERS活性位點。 最后，對實際食品樣品中的硝基呋喃類抗生素以加標(biāo)提取的方式進行了SERS檢測。由于食品體系較為復(fù)雜，對SERS檢測存在一定的干擾，硝基呋喃類抗生素分子能夠被增強的的特征振動較少，但分子結(jié)構(gòu)中的主要振動即呋喃環(huán)、NO_2、C=N所有增強，表明該方法可對實際食品樣品中硝基呋喃類抗生素實現(xiàn)簡單的定性鑒別，在食品違禁添加劑的快速篩查方面具有一定的潛力。
[Abstract]:Nitrofuran antibiotics are a class of broad-spectrum antimicrobial agents, including furazolidone, furantoin, furantoin, furantoin, and furantadone, which have been widely used as additives in feed and veterinary drugs because of their proven potential toxicity to animals and animals. Mutagenicity and carcinogenicity have been banned by many countries in recent years. However, the use of nitrofuran antibiotics is still exposed because of its low price and obvious efficacy. Surface enhanced Raman spectroscopy (SERS) is based on Raman spectroscopy. A technique for obtaining material molecular fingerprint information by virtue of the special optical properties of the surface of nanomaterials, which has been developed rapidly in recent years because of its advantages of fast, nondestructive, low consumption and accuracy. This study is intended to be carried out by means of SERS technology. A rapid method for the detection of nitrofuran antibiotics was established by assisted synthesis and modification of nanomaterials. Firstly, the characteristic Raman vibration of nitrofuran antibiotics is theoretically analyzed by density functional theory (DFT). It is determined that the Raman characteristic vibration is mainly 1 602 cm ~ (-1). The NO_2 asymmetric stretching vibration is determined to be the symmetrical stretching vibration in the Con N plane (1556 cm ~ (-1)), and its Raman characteristic vibration is determined to be 1 602 cm ~ (-1) ~ (-1). The symmetrical stretching vibration of furan ring is 1 484 cm ~ (-1), the H-C-H symmetric stretching vibration of furan ring is 1336 cm ~ (-1), and the C-N-N symmetric stretching vibration of furan ring is 1220 cm ~ (-1). Secondly, the classical au sol and magnetic core-shell nanomaterials were prepared, and their morphology and detection conditions were analyzed. The optimum experimental conditions were established by comparing the enhancement effect of SERS. Firstly, acetone should be used as solvent when au sol was used as the active substrate of SERS. When the volume ratio of sample to substrate is 1: 2, the minimum detection limit of N _ 1N _ 2N _ 2N _ 4 can reach 5 ppm when the pH value of the system is adjusted to 3.0 ~ 4.0, but N _ 3 can not be detected because of the particularity of N _ 3 molecular structure which makes it difficult for the Raman active group of N _ 3 to fully contact the surface of au sol. When magnetic core-shell material is used as substrate, the thickness of Ag shell is about 40nm on Fe_3O_4@Ag substrate, the concentration of substrate is 0.5g / ml, the excitation wavelength is 633nm, and the minimum detection limit of four substances can reach 0.1 ppm. at the same time, L- cysteine was modified on the surface of Fe_3O_4@Ag by molecular assembly technique. The results show that N3 can obtain better SERS effect on the substrate. The SERS effects of the above two substrates are compared in reproducibility. The conclusion is that the SERS effect of the substrate Fe_3O_4@Ag is the best, because the morphology, distribution and spacing of the Fe_3O_4@Ag are more uniform, which is beneficial to stimulate the SERS effect. Moreover, the surface roughness of Ag shell is higher and the surface area is larger, which can provide more SERS active sites. Finally, the nitrofuran antibiotics in real food samples were detected by SERS with standard extraction. Because of the complexity of food system, the detection of SERS was interfered to a certain extent. The characteristic vibration of nitrofuran antibiotics can be enhanced less, but the main vibration in molecular structure is all enhanced, which indicates that this method can be used for simple qualitative identification of nitrofuran antibiotics in real food samples. There is a certain potential for rapid screening of food additives.
【學(xué)位授予單位】：江南大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2013
【分類號】：R155.5

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本文編號：1504879