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Title: | 次氯酸鈉氧化Isoluminol之化學發光研究:β-環糊精增強效應及應用 Study of Chemiluminescence from the Oxidation of Isoluminol by Sodium Hypochlorite:Enhancement with β-Cyclodextrin and Its Application |
Authors: | JEN-YI FANG 方仁義 |
Advisor: | 林萬寅 |
Keyword: | β-環糊精,化學發光, β-cyclodextrin,chemiluminescence, |
Publication Year : | 2005 |
Degree: | 碩士 |
Abstract: | 化學發光因具高選擇性、低雜訊干擾、靈敏度高、分析速度快及儀器簡單等優點,近來已大量應用在分析化學領域上。本研究利用停止流光譜儀探討β-環糊精對次氯酸鈉氧化isoluminol所產生之化學發光之增強效應,並利用此化學發光系統來偵測各種抗氧化物。其內容包含溶液酸鹼度、β-環糊精濃度、化學發光試劑(isoluminol)濃度及氧化劑(次氯酸鈉)濃度對化學發光影響的探討。由實驗結果得知,系統的pH值對化學發光有很大的影響。在無添加任何的β-環糊精下,化學發光系統在pH = 10.0時有最大發光強度;而在添加5 mM的β-環糊精後,化學發光系統在pH = 8.5時有最大發光強度。β-環糊精在系統酸鹼度為pH = 8.5時,有最大的增強倍率,可將原本微弱的化學發光增強約90倍左右。這是因為β-環糊精內圈的空腔,可與化學發光試劑形成包絡物,在反應時保護分子不受溶液中其他分子的碰撞,進而增加系統的量子產率,提高發光效率,增強化學發光強度。此外,化學發光強度隨著isoluminol濃度增加(0 μM∼90 μM)而線性增強;次氯酸鈉濃度的增加也造成化學發光強度增強,但在較高濃度(> 100 μM)時漸趨於飽和。
最後,我們以前述之最佳反應條件來偵測Trolox、Curcumin、Quinic acid、BHA、Sesamol、L-ascorbic acid及Hydroquinone等抗氧化劑。因為抗氧化劑富含羥基(OH group),可以消除反應時所產生的自由基,進而抑制化學發光。由實驗結果發現,除L-ascorbic acid與Hydroquinone在低濃度時,對isoluminol/β-環糊精/次氯酸鈉發光系統有增強化學發光現象外,其餘抗氧化劑均有明顯抑制化學發光。無論化學發光強度的增強或抑制都可用於定量該化合物。這些抗氧化劑的半抑制濃度分別約為7.09 μM(Sesamol)、19.9 μM(BHA)、26.2 μM(Curcumin)、203.2 μM(Trolox)及3.3 mM(Quinic acid)。 Chemical analysis based on chemiluminescence(CL) has been widely used because of its high sensitivity and selectivity, wide dynamic range, fast measurements, and simple instrumentation. In this research, we have studied the enhancement of CL by β-cyclodextrin from the oxidation of isoluminol with hypochlorite. We have also optimized the CL system to determine the antioxidants. The CL system exhibited an optimal pH of 10.0 in the absence of β-cyclodextrin. The CL emission was dramatically enhanced upon addition of β-cyclodextrin, especially at pH below 9.5. In the presence of 5mM β-cyclodextrin , the optimal pH was 8.5 and the maximum enhancement was 90 folds. The CL emission increases as the concentration of isoluminol or hypochlorite increases. Antioxidants are capable of scavenging the radicals involved in CL reaction, thereby inhibiting the CL emission. The CL system has been employed to determine the antioxidants. The obtained IC50 (concentration at half-inhibition of CL) of several antioxidants are : sesamol (7.09μM)、BHA (19.9μM)、curcumin (26.2μM)、trolox (203.2μM) and quinic acid (3.3mM). In contrast to the inhibitory effect of most antioxidants , L-ascorbic acid and hydroquinone further enhance the CL emission up to 13- and 8-fold, respectively. The reason for the extra CL enhancement is still not clear. This enhancement can also be used to quantify those two compounds . |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/36793 |
Fulltext Rights: | 有償授權 |
Appears in Collections: | 化學系 |
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