發(fā)布時間：2018-05-21 14:56

  本文選題：量子點(diǎn) + pH檢測��； 參考：《上海應(yīng)用技術(shù)大學(xué)》2017年碩士論文

【摘要】：在化學(xué)、生物醫(yī)學(xué)、環(huán)境等各種領(lǐng)域,監(jiān)控氫離子(H+)濃度是非常重要的,發(fā)展一種快速檢測pH值的方法是非常有意義的。在熒光分析領(lǐng)域,憑借著成熟、簡便的合成方法和獨(dú)特的發(fā)光性質(zhì),半導(dǎo)體納米晶作為替代有機(jī)熒光基團(tuán)的替代者己經(jīng)嶄露頭角。本論文在調(diào)研文獻(xiàn)的基礎(chǔ)上,設(shè)計(jì)并合成了兩種基于CdSe/ZnS量子點(diǎn)的pH熒光探針,對其性能和檢測機(jī)理進(jìn)行了研究,主要研究內(nèi)容包括以下兩個部分:第一部分以發(fā)射峰為610 nm的CdSe/ZnS核殼量子點(diǎn)為熒光團(tuán),對巰基苯胺(pATP)作為氫離子敏感的功能配體,通過在量子點(diǎn)表面進(jìn)行配體交換制得一種熒光恢復(fù)型pH熒光探針(pATP-QDs),并利用各種手段進(jìn)行表征,如紫外吸收光譜、傅里葉變換紅外光譜、熒光光譜、熒光壽命等。由于pATP是一個空穴受體,pATP-QDs表現(xiàn)出弱熒光。作為有機(jī)堿,pATP很容易接受H+被質(zhì)子化,質(zhì)子化后的結(jié)構(gòu)(pATP-H+)改變pATP原有的最高占有分子軌道(HOMO)的能級,從而抑制了量子點(diǎn)的空穴轉(zhuǎn)移過程,量子點(diǎn)的熒光恢復(fù)。熒光"off-on"模式、高的量子產(chǎn)率、pATP-H+穩(wěn)定性讓pATP-QDs表現(xiàn)出了良好的pH檢測性能。在優(yōu)化條件下,熒光響應(yīng)和pH值(pH 3.2～6.0)之間具有好的線性關(guān)系。此外,pATP-QDs對H+表現(xiàn)出了高的選擇性表現(xiàn)出了高的選擇性并成功的應(yīng)用到實(shí)際水樣的pH檢測。第二部分是以發(fā)射峰為581 nm的CdSe/ZnS核殼量子點(diǎn)為熒光團(tuán),用對巰基苯酚(HOPhSH)進(jìn)行表面配體交換過程后去質(zhì)子化得到pH探針(-OPhS-QDs)。-OPhS-QDs能夠作為一種選擇性的熒光"on-off"的熒光探針用于水溶液中pH的檢測。-OPhS-QDs在近中性溶液中表現(xiàn)出強(qiáng)熒光。根據(jù)路易斯酸堿理論,量子點(diǎn)表面的酚鹽(-OPhS)對H+敏感,-OPhS-QDs在一定的酸性溶液中能夠與H+反應(yīng)生成HOPhS-QDs。而HOPhS是高效的空穴受體,結(jié)果使得量子點(diǎn)的熒光淬滅。在優(yōu)化條件下,在pH 3.0～5.2范圍,熒光響應(yīng)和pH值之間具有好的線性關(guān)系。此外,-OPhS-QDs對H+表現(xiàn)出了高的選擇性并成功的應(yīng)用到實(shí)樣的pH檢測。
[Abstract]:In chemistry, biomedicine, environment and other fields, it is very important to monitor the concentration of hydrogen ion (H), so it is very important to develop a rapid method to detect pH value. In the field of fluorescence analysis, semiconductor nanocrystals have emerged as substitutes for organic fluorescent groups due to their mature, simple synthesis methods and unique luminescent properties. In this paper, two kinds of pH fluorescence probes based on CdSe/ZnS quantum dots are designed and synthesized, and their properties and detection mechanism are studied. The main research contents include the following two parts: in the first part, the CdSe/ZnS core-shell quantum dots with emission peak of 610nm were used as fluorescence groups, and p-mercaptoaniline pATP was used as the hydrogen-ion-sensitive functional ligand. A fluorescence recovery pH fluorescence probe pATP-QDsN was prepared by ligand exchange on the surface of quantum dots, and characterized by various methods, such as UV absorption spectrum, Fourier transform infrared spectroscopy, fluorescence lifetime and so on. Because pATP is a hole receptor, pATP-QDs exhibit weak fluorescence. As an organic base, it is easy to accept the protonation of H, and the protonated structure (pATP-H) changes the energy level of the original highest occupied molecular orbital of pATP, which inhibits the hole transfer process of quantum dots and the fluorescence recovery of quantum dots. Fluorescence "off-on" mode, high quantum yield and pATP-H stability make pATP-QDs have good pH detection performance. Under the optimized conditions, there was a good linear relationship between the fluorescence response and pH value (pH 3.2 ~ 6.0). In addition, pATP-QDs showed high selectivity to H and were successfully applied to the pH detection of real water samples. In the second part, CdSe/ZnS core-shell quantum dots with emission peak of 581nm are used as fluorescence groups. The pH probe (-OPhS-QDsN. -OPhS-QDs) can be used as a selective fluorescent "on-off" fluorescence probe to detect pH in aqueous solution. OPhS-QDs show strong fluorescence in near-neutral solution. According to Lewis acid-base theory, the phenolic salts on the surface of quantum dots can react with H to form HOPhS-QDs in a certain acid solution. HOPhS is an efficient hole receptor, resulting in fluorescence quenching of quantum dots. Under the optimized conditions, there is a good linear relationship between the fluorescence response and pH value in the range of pH 3.0 ~ 5.2. In addition, OPhS-QDs showed high selectivity to H and were successfully applied to the pH detection of real samples.
【學(xué)位授予單位】：上海應(yīng)用技術(shù)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：O657.3;TB383.1

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