目標(biāo)物誘導(dǎo)的量子點熒光淬滅及其應(yīng)用
發(fā)布時間：2019-02-16 02:47
【摘要】：目前,量子點因具有優(yōu)良的熒光性能而得到了廣泛的關(guān)注,在無機離子檢測、藥物分析等領(lǐng)域應(yīng)用廣泛。本文合成了CdS量子點和碳點,并將其成功地應(yīng)用于環(huán)境中污染物的檢測。首先,實驗發(fā)現(xiàn),全氟辛酸(Perfluorooctanoic acid,PFOA)能選擇性淬滅巰基丙酸修飾的CdS量子點熒光。其淬滅機理是PFOA的羧基和CdS量子點表面的羧基相結(jié)合后吸附至量子點表面,再通過PFOA的氟原子之間的相互作用(氟-氟親和作用)使量子點團聚,導(dǎo)致其熒光發(fā)生淬滅。據(jù)此建立了檢測PFOA的熒光新方法。在優(yōu)化條件下,PFOA濃度在0.5~40μmol L-1范圍內(nèi)與體系的熒光淬滅效率(F/F0)之間存在良好的線性關(guān)系,檢出限為0.3μmol L-1。采用此法對紡織品樣品中PFOA的含量進行了測定,其加標(biāo)回收率在95.0%~113.0%之間。其次,發(fā)現(xiàn)在pH為4.0的醋酸鹽緩沖溶液中,Fe3+對以苯硼酸為前驅(qū)體合成的富含羥基的碳點的熒光有很明顯的淬滅作用,而其它金屬離子不能淬滅其熒光。研究表明,其淬滅過程包括動態(tài)和靜態(tài)淬滅兩種方式:Fe3+通過靜電引力吸附到碳點表面,由于Fe3+是很強的電子接受體,吸附于碳點表面的Fe3+可接受碳點受光激發(fā)產(chǎn)生的光生電子而被還原為Fe2+,與此同時Fe3+又可與碳點表面的羥基結(jié)合使碳點團聚,這兩種作用均導(dǎo)致碳點的熒光淬滅。據(jù)此建立了選擇性測定鐵的熒光方法。Fe3+濃度在1.0~250?mol L-1范圍內(nèi)與體系的熒光淬滅效率(ln[F0/F])有良好的線性關(guān)系,檢出限為0.4?mol L-1。本法用于奶粉中鐵含量的測定,結(jié)果令人滿意。此外,根據(jù)Fe3+可大幅度淬滅碳點的熒光,而Fe2+不能淬滅碳點的熒光之特性,利用Feton反應(yīng),使用H2O2將Fe2+氧化為Fe3+,建立了一種基于Fe3+淬滅碳點熒光而間接測定H2O2的新方法。該方法的線性范圍為0.7~500?mol L-1,檢出限為0.2?mol L-1。采用此方法測定了一次性筷子中H2O2的殘留量,結(jié)果與鈦鹽比色法的測定結(jié)果相符合。另外,還發(fā)現(xiàn)EDTA能淬滅碳點-Fe2+混合體系的熒光,據(jù)此建立了一種測定EDTA的新方法。該方法的線性范圍為1.0~150?mol L-1,檢出限為0.4?mol L-1。采用此法測定了自來水和湖水中EDTA的含量,其回收率在95.2%~106.5%之間。
[Abstract]:At present, quantum dots (QDs) have been widely used in inorganic ion detection, drug analysis and other fields because of their excellent fluorescence properties. CdS quantum dots and carbon dots have been synthesized and successfully applied to the detection of pollutants in the environment. Firstly, it was found that perfluorooctanoic acid (Perfluorooctanoic acid,PFOA) can selectively quench the fluorescence of CdS quantum dots modified by mercaptopropionic acid. The mechanism of quenching is that the carboxyl group of PFOA and the carboxyl group on the surface of CdS quantum dot are adsorbed to the surface of quantum dot, and then the fluorine atom interaction (fluorine-fluorine affinity) of PFOA makes the quantum dot agglomerate, resulting in the fluorescence quenching of the quantum dot. A new fluorescence method for the detection of PFOA was established. Under the optimum conditions, there is a good linear relationship between the concentration of PFOA in the range of 0.5 渭 mol L-1 and the fluorescence quenching efficiency (F/F0) of the system, and the detection limit is 0.3 渭 mol L-1. The content of PFOA in textile samples was determined by this method. The recoveries of PFOA in textile samples were between 95.0% and 113.0%. Secondly, it was found that in the acetate buffer solution with pH 4.0, Fe3 had obvious quenching effect on the hydroxyl rich carbon point synthesized from phenylboric acid, but other metal ions could not quench the fluorescence. The results show that the quenching process consists of dynamic and static quenching: Fe3 is adsorbed to the surface of carbon point by electrostatic gravitation, because Fe3 is a very strong electron acceptor. The Fe3 adsorbed on the surface of the carbon point can be reduced to Fe2 by photoinduced electrons generated by the carbon point. At the same time, the Fe3 can combine with the hydroxyl group on the surface of the carbon point to make the carbon point agglomerate. Both of these actions lead to the fluorescence quenching of the carbon point. A fluorescence method for the selective determination of iron was established. The fluorescence quenching efficiency (ln [F _ 0 / F]) of the system was linear in the range of 1.0~250?mol L ~ (-1) for Fe3, and the detection limit was 0.4?mol L ~ (-1). The method has been applied to the determination of iron in milk powder with satisfactory results. In addition, according to the characteristic that Fe3 can greatly quench the fluorescence of carbon point, but Fe2 can not quench the fluorescence of carbon point, using Feton reaction, Fe2 is oxidized to Fe3 by H2O2, and a new method for indirect determination of H2O2 based on Fe3 quenching carbon point fluorescence is established. The linear range of the method is 0.7~500?mol L -1 and the detection limit is 0.2?mol L -1. The residue of H2O2 in disposable chopsticks was determined by this method. The results were in agreement with the results of titanium salt colorimetry. In addition, it was found that EDTA can quench the fluorescence of the mixture of carbon point and Fe2, and a new method for the determination of EDTA was established. The linear range of the method is 1.0~150?mol L -1 and the detection limit is 0.4?mol L -1. This method was used to determine the content of EDTA in tap water and lake water. The recovery was between 95.2% and 106.5%.
【學(xué)位授予單位】：華中科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：O657.3;X830.2
[Abstract]:At present, quantum dots (QDs) have been widely used in inorganic ion detection, drug analysis and other fields because of their excellent fluorescence properties. CdS quantum dots and carbon dots have been synthesized and successfully applied to the detection of pollutants in the environment. Firstly, it was found that perfluorooctanoic acid (Perfluorooctanoic acid,PFOA) can selectively quench the fluorescence of CdS quantum dots modified by mercaptopropionic acid. The mechanism of quenching is that the carboxyl group of PFOA and the carboxyl group on the surface of CdS quantum dot are adsorbed to the surface of quantum dot, and then the fluorine atom interaction (fluorine-fluorine affinity) of PFOA makes the quantum dot agglomerate, resulting in the fluorescence quenching of the quantum dot. A new fluorescence method for the detection of PFOA was established. Under the optimum conditions, there is a good linear relationship between the concentration of PFOA in the range of 0.5 渭 mol L-1 and the fluorescence quenching efficiency (F/F0) of the system, and the detection limit is 0.3 渭 mol L-1. The content of PFOA in textile samples was determined by this method. The recoveries of PFOA in textile samples were between 95.0% and 113.0%. Secondly, it was found that in the acetate buffer solution with pH 4.0, Fe3 had obvious quenching effect on the hydroxyl rich carbon point synthesized from phenylboric acid, but other metal ions could not quench the fluorescence. The results show that the quenching process consists of dynamic and static quenching: Fe3 is adsorbed to the surface of carbon point by electrostatic gravitation, because Fe3 is a very strong electron acceptor. The Fe3 adsorbed on the surface of the carbon point can be reduced to Fe2 by photoinduced electrons generated by the carbon point. At the same time, the Fe3 can combine with the hydroxyl group on the surface of the carbon point to make the carbon point agglomerate. Both of these actions lead to the fluorescence quenching of the carbon point. A fluorescence method for the selective determination of iron was established. The fluorescence quenching efficiency (ln [F _ 0 / F]) of the system was linear in the range of 1.0~250?mol L ~ (-1) for Fe3, and the detection limit was 0.4?mol L ~ (-1). The method has been applied to the determination of iron in milk powder with satisfactory results. In addition, according to the characteristic that Fe3 can greatly quench the fluorescence of carbon point, but Fe2 can not quench the fluorescence of carbon point, using Feton reaction, Fe2 is oxidized to Fe3 by H2O2, and a new method for indirect determination of H2O2 based on Fe3 quenching carbon point fluorescence is established. The linear range of the method is 0.7~500?mol L -1 and the detection limit is 0.2?mol L -1. The residue of H2O2 in disposable chopsticks was determined by this method. The results were in agreement with the results of titanium salt colorimetry. In addition, it was found that EDTA can quench the fluorescence of the mixture of carbon point and Fe2, and a new method for the determination of EDTA was established. The linear range of the method is 1.0~150?mol L -1 and the detection limit is 0.4?mol L -1. This method was used to determine the content of EDTA in tap water and lake water. The recovery was between 95.2% and 106.5%.
【學(xué)位授予單位】：華中科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：O657.3;X830.2
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