【摘要】：甲烷氧化菌是甲基菌中的一個分支,它是一種革蘭氏陰性菌,直接以甲烷為能源和碳源。甲烷氧化菌素(Methanobactin,Mb)是甲烷氧化菌向周圍釋放出的一種熒光肽,它由兩個絲氨酸、甘氨酸、色氨酸、兩個半胱氨酸、蛋氨酸組成,含有與銅高度絡(luò)合2個氧唑N和2個硫酰S。甲烷氧化菌素能結(jié)合和催化還原Au(Ⅲ)為Au(0)。在有對苯二酚的參與下,能夠為甲烷氧化菌素還原Au(Ⅲ)提供電子供體,可以持續(xù)生成金納米顆粒,由于金納米顆粒具有等離子體共振效應(yīng),在用紫外可見吸收光譜掃描在500nm到600nm范圍內(nèi)有明顯的特征吸收峰,呈現(xiàn)出特殊的顏色,可以用肉眼所識別的顏色變化可以完成某些物質(zhì)的檢測。 近幾年來蛋白質(zhì)飼料中添加三聚氰胺的范圍幾乎涵蓋了整個飼料行業(yè),牛羊飼料、禽飼料、豬飼料和水產(chǎn)飼料、寵物飼料都或多或少地混有“三聚氰胺”,三聚氰胺的加入明顯增加了食物中的含氮量,因此迫切需要建立一種簡便、有效分析蛋白質(zhì)飼料和其他食品中的三聚氰胺的快速檢測方法。 本論文利用甲烷氧化菌素介導(dǎo)納米金合成過程可視化的檢測蛋白質(zhì)飼料中的三聚氰胺,方便、快捷,檢測極限遠(yuǎn)遠(yuǎn)低于國家規(guī)定的三聚氰胺的1ppm標(biāo)準(zhǔn)。對蛋白質(zhì)飼料中不同濃度的三聚氰胺進(jìn)行了檢測,考察了蛋白質(zhì)飼料中幾種成分對檢測的干擾,計算了該方法的檢測限及三聚氰胺的加標(biāo)回收率。 1、甲烷氧化菌素可以以對苯二酚作為外源電子供體催化Au(Ⅲ)持續(xù)還原形成納米金。研究了金納米粒子的最佳合成條件,PH=5.1,甲烷氧化菌素Au(Ⅲ)的摩爾比在0.8：1,對苯二酚:Au(Ⅲ)的摩爾比在0.4：1,納米金隨著反應(yīng)的繼續(xù)會越來越多,待到反應(yīng)結(jié)束,并對制備的納米金溶液進(jìn)行了紫外可見吸收光譜、透射電鏡(TEM)分析。 2、研究了甲烷氧化菌素介導(dǎo)納米金合成過程中檢測三聚氰胺的機(jī)理,由于甲烷氧化菌素可以還原Au(Ⅲ)形成納米金,溶液呈現(xiàn)酒紅色或葡紫色,而三聚氰胺可以抑制甲烷氧化菌素還原Au(Ⅲ)形成納米金,所以溶液沒有顏色變化,通過比色法可以很直觀的檢測三聚氰胺,通過紫外可見吸收光譜對加入三聚氰胺和未加入三聚氰胺的樣品在200nm到800nm范圍內(nèi)進(jìn)行掃描,可以發(fā)現(xiàn)未加入三聚氰胺的在500nm到600nm內(nèi)有明顯的特征吸收峰,證明有金納米顆粒的形成,加入三聚氰胺的則在此范圍內(nèi)沒有吸收峰,說明沒有金納米顆粒的生成。檢測三聚氰胺的最佳條件,室溫下,PH=5.1,甲烷氧化菌素Au(Ⅲ)在0.7：1,對苯二酚Au(Ⅲ)在0.25：1的條件下,對不同濃度的三聚氰胺進(jìn)行檢測了實驗,檢測最低限達(dá)到了0.6ppm,遠(yuǎn)遠(yuǎn)低于國家標(biāo)準(zhǔn)的1ppm. 3、檢測蛋白質(zhì)飼料中的三聚氰胺原理是依據(jù)是三聚氰胺能阻止甲烷氧化菌素催化還原Au(Ⅲ)生成納米金,通過比色法來檢測三聚氰胺。實驗表明,三聚氰胺的濃度與此濃度下形成的金納米顆粒有著良好的線性關(guān)系,用紫外可見吸收光譜可以實現(xiàn)定量的檢測,檢測范圍在0.05ppm到0.5ppm。用肉眼檢測限度為0.6ppm,加標(biāo)回收率在97-103%。通過紫外可見吸收光譜對可能存在的干擾因素檢測發(fā)現(xiàn)只有Vb12及V。有非常小的影響。
[Abstract]:Methanobactin (Mb) is a fluorescent peptide released from methane-oxidizing bacteria. It consists of two serine, glycine, tryptophan, two cysteines, and methionine, which are high in copper. Complexing 2 Oxazoles N with 2 thionyl S. methane oxidizing bacteriocins can bind and catalyze the reduction of Au (III) to Au (0). With the participation of hydroquinone, it can provide electron donors for the reduction of Au (III) by methane oxidizing bacteriocins, and can continuously form gold nanoparticles. Because of the plasma resonance effect of gold nanoparticles, ultraviolet-visible absorption spectroscopy is used to scan the gold nanoparticles. The trace has obvious characteristic absorption peaks in the range of 500 nm to 600 nm, showing a special color, which can be used to detect certain substances by the color change recognized by the naked eye.
In recent years, the range of melamine added to protein feed has covered almost all the feed industry, * cattle and sheep feed, poultry feed, pig feed and aquatic feed, and pet feed mixed with melamine more or less. The addition of melamine significantly increased the nitrogen content in food. Therefore, it is urgent to establish a simple and effective method. A rapid method for the determination of melamine in protein feed and other foods.
Melamine in protein feed was detected visually by methane oxidizing bacteriocin-mediated synthesis of gold nanoparticles in this paper. It was convenient, rapid and the detection limit was far lower than the 1 ppm standard of melamine stipulated by the state. The detection limit and the recovery rate of melamine were calculated.
1. Hydroquinone can be used as an external electron donor to catalyze the continuous reduction of Au (III) to form gold nanoparticles. The optimum conditions for the synthesis of gold nanoparticles were studied. The molar ratio of Au (III) to methane oxidizing bacteriocin was 0.8:1, and the molar ratio of hydroquinone to Au (III) was 0.4:1. At the end of the reaction, ultraviolet-visible absorption spectra and transmission electron microscopy (TEM) were used to analyze the gold nanoparticles.
2. The mechanism of detecting melamine in the process of synthesizing Gold Nanoparticles Mediated by methane oxidizing bacteriocin was studied. Because methane oxidizing bacteriocin can reduce Au (III) to form gold nanoparticles, the solution appears wine red or purple, while melamine can inhibit the reduction of Au (III) to form gold nanoparticles by methane oxidizing bacteriocin, so the solution has no color change through colorimetry. The method can be used to detect melamine directly. The samples with and without melamine were scanned in the range of 200 nm to 800 nm by UV-Vis absorption spectroscopy. It was found that there were obvious characteristic absorption peaks in the range of 500 nm to 600 nm without melamine. It was proved that gold nanoparticles were formed and melamine was added. At room temperature, PH = 5.1, methane oxidizing bacteriocin Au (III) at 0.7:1, hydroquinone Au (III) at 0.25:1, the detection limit of different concentrations of melamine reached 0.6 ppm, far below. National standard 1ppm.
3. The principle of detecting melamine in protein feed is based on the fact that melamine can prevent the catalytic reduction of Au (III) by methane oxidizing bacteriocin to form gold nanoparticles. Melamine is detected by colorimetric method. The experimental results show that the concentration of melamine has a good linear relationship with the gold nanoparticles formed at this concentration. The UV-Vis absorption spectrum is used. Quantitative detection can be achieved with a detection range of 0.05 ppm to 0.5 ppm. The detection limit is 0.6 ppm with the naked eye, and the recovery rate is 97-103%. Only Vb12 and V. have very small influence on the possible interference factors detected by UV-Vis absorption spectroscopy.
【學(xué)位授予單位】：哈爾濱商業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：O657.32;S816.4

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