【摘要】：石墨烯量子點(GQDs)是一種新型的具有熒光性能的碳基準(zhǔn)零維納米材料,其定義為橫向尺寸小于100 nm的單層、雙層和3-10層的石墨烯片。GQDs的比表面積大且外邊緣有羥基和羧基等基團(tuán),因此具有易于修飾的特點。在經(jīng)過化學(xué)修飾的量子點中,化學(xué)鍵合氮原子合成的氮摻雜石墨烯量子點(N-GQDs)與GQDs相比具有量子產(chǎn)率高、熒光強(qiáng)度高、水溶性好、生物毒性低、生物相容性好等優(yōu)勢,因此在熒光檢測、環(huán)境監(jiān)測、光電器件、生物成像等領(lǐng)域中具有良好的發(fā)展前景。在本論文工作中,結(jié)合本實驗室在量子點制備方面的基礎(chǔ)工作,分別以檸檬酸和脲作為碳源和氮源,采用水熱法一步合成了N-GQDs,并分別用紫外-可見光譜、透射電子顯微鏡、X射線衍射儀、X射線光電子能譜及熒光光譜對其進(jìn)行了表征,研究其結(jié)構(gòu)特性,構(gòu)建了N-GQDs相關(guān)的熒光檢測體系,并進(jìn)一步對實際樣品中四環(huán)素(TC)、抗壞血酸(AA)、鐵的形態(tài)進(jìn)行了分析。主要內(nèi)容如下:1.N-GQDs在TC定量檢測中的應(yīng)用。通過水熱法一步合成了平均直徑為4.4±0.6nm的N-GQDs,與GQDs相比具有更強(qiáng)的熒光性質(zhì),在pH和離子強(qiáng)度等條件下更穩(wěn)定,并表現(xiàn)出藍(lán)移的特性。在優(yōu)化pH、反應(yīng)溫度、反應(yīng)時間等實驗條件的基礎(chǔ)上,利用TC對N-GQDs的熒光猝滅作用建立了一種測定TC的熒光分析新方法,檢測TC的線性范圍為0.20 20μmol·L-1,檢出限(3σ,n=11)為1.62 nmol·L-1。與其他的分析技術(shù)相比,此熒光猝滅方法從檢測限、線性范圍等方面都展現(xiàn)出更優(yōu)良的分析性能,并成功應(yīng)用于檢測牛奶樣品中TC的含量。2.N-GQDs在AA定量檢測中的應(yīng)用�；贔e(Ⅲ)和Fe(II)對N-GQDs熒光的不同猝滅效果,發(fā)展了一種熒光增強(qiáng)型探針并應(yīng)用于飲料樣品中AA的選擇性檢測。首先通過N-GQDs和Fe(Ⅲ)之間的非輻射電子轉(zhuǎn)移猝滅N-GQDs的熒光以測定Fe(Ⅲ),加入AA后,Fe(Ⅲ)與AA之間發(fā)生氧化還原反應(yīng)使Fe(Ⅲ)轉(zhuǎn)化為Fe(II),因為Fe(II)對N-GQDs的熒光無明顯猝滅作用,從而導(dǎo)致N-GQDs熒光得以恢復(fù)。該傳感器對AA有很好的選擇性,線性范圍為1.0 90μmol·L-1,檢出限(3σ,n=11)是18 nmol·L-1,并成功應(yīng)用于測定飲料樣品中AA的含量。3.N-GQDs在鐵形態(tài)分析中的應(yīng)用�；贔e(Ⅲ)對N-GQDs的熒光猝滅效果測定Fe(Ⅲ),并分別對自然水樣中的Fe(II)和Fe(Ⅲ)進(jìn)行定量分析,達(dá)到對鐵進(jìn)行形態(tài)分析的目的。首先通過Fe(Ⅲ)對N-GQDs的熒光猝滅作用測定Fe(Ⅲ)和總鐵濃度,Fe(tot)中包括過氧化氫氧化Fe(II)得到的Fe(Ⅲ),Fe(II)可以從Fe(tot)中減去Fe(Ⅲ)得到。檢測Fe(Ⅲ)的線性范圍為0.0100-200μmol·L-1,檢出限(3σ,n=11)為4.24 nmol·L-1,這種方法與之前報道過的鐵形態(tài)分析方法相比簡單且避免了冗雜的實驗配置,具有靈敏度高、易于操作等優(yōu)點,并且實驗結(jié)果表明該方法可以對自然水體中的溶解鐵進(jìn)行形態(tài)分析。
[Abstract]:Graphene Quantum Dot (GQDs) is a new carbon reference zero dimensional nano-material with fluorescence properties, which is defined as a single layer with transverse size less than 100 nm. The surface area of GQDs is large and there are hydroxyl and carboxyl groups on the outer edge, so it is easy to modify. In chemically modified quantum dots, nitrogen-doped graphene quantum dots (N-GQDs) synthesized by chemically bonded nitrogen atoms have the advantages of higher quantum yield, higher fluorescence intensity, better water solubility, lower biotoxicity and better biocompatibility than those of GQDs. Therefore, it has a good prospect in the fields of fluorescence detection, environmental monitoring, optoelectronic devices, biological imaging and so on. In this paper, N-GQDs were synthesized by hydrothermal method with citric acid and urea as carbon source and nitrogen source, respectively, combined with the basic work of our laboratory in the preparation of quantum dots. Transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and fluorescence spectroscopy (FRS) were used to characterize the structure of the system. The N-GQDs related fluorescence detection system was constructed, and the tetracycline (TC), in real samples was further determined. The morphology of (AA), iron ascorbic acid was analyzed. The main contents are as follows: the application of 1.N-GQDs in quantitative detection of TC. N-GQDs with an average diameter of 4.4 鹵0.6nm were synthesized by hydrothermal method in one step. Compared with GQDs, N-GQDs have stronger fluorescence properties and are more stable under the conditions of pH and ionic strength, and exhibit the characteristics of blue shift. On the basis of optimizing the reaction temperature and reaction time of pH, a new method for the determination of TC by fluorescence quenching of N-GQDs by TC was established. The linear range of detection of TC was 0.20 渭 mol L ~ (-1). The detection limit (3 蟽, nni11) is 1. 62 nmol L ~ (-1). Compared with other analytical techniques, this fluorescence quenching method showed better analytical performance in terms of detection limit and linear range, and was successfully applied to the determination of TC in milk samples. 2.N-GQDs was applied to the quantitative detection of AA. Based on the different quenching effects of Fe (鈪，

本文編號：2296368