環糊精改質之紅外光感測器檢測水中高極性有機化合物之行為探討

Studies of cyclodextrin modified infrared chemical sensors in detection of high polarity compounds in aqueous solutions.

林宏哲(Hung-Che Lin)

指導教授 ： 楊吉斯 ； 黃悉雅

中原大學/理學院/化學研究所/博士(2003年)

https://doi.org/10.6840/cycu200300562

摘要

中文摘要

紅外光感測器在測量水中有機物質時，常受限於覆膜層的穩定性問題，而無法對高極性化合物作一有效測量；且在單一的光譜分析下，難以區分樣品和覆膜的結合模式；因此，本研究提出以環糊精（cyclodextrin，CD）改質覆膜，藉以利用其量測苯環酸類物質，並可經由動量數據與理論推導，加以確認吸附行為的分析機制。此外，為了有效提昇高極性覆膜層的水穩定性，將不同大小之環糊精，以化學修飾的方法固定於硒化鋅（ZnSe）晶體表面，並控制於適當的駐波範圍中，其衍生效率及反應條件的找尋方面，可輕易地利用紅外光吸收來加以追蹤獲得；而且改質後的感測晶體亦具有極高的穩定度。所使用的減弱式全反射法（Attenuated Total Reflection，ATR）分析機制，對於分析物有極佳的靈敏度。多數的苯環酸類分析樣品於環糊精覆膜中，能呈現良好的吸附現象。本論文中亦加以探討：吸附速率、樣品選擇性、CD含量、pH效應，與覆膜再生等因素，對感測所造成的影響。

另一焦點，則著重於由紅外光譜之吸附曲線的結果所推論獲得，環糊精與分析物的動力行為；其結合物呈現出兩者間的結構關係，及相互吸引的型態；而由其結合模式，可從中區分出二種行為：其一為快速吸附，並且能於數分鐘之內達到平衡，而形成飽和狀態；另一則為分子是以緩慢的速度移動至結構凹槽處，再與其結合。此二種的吸附行為，可藉由二維的Exponential曲線修正來加以證實。

因此，對於紅外光譜研究而言；IR/ATR與CD修飾覆膜結合，及其感測系統的建立，不僅僅提供了苯環酸類分析物最佳的感測方法，並且亦能精確的區分出樣品之行為模式，與提供其相互之間的關聯性。

關鍵字

結合物 ； 苯環酸 ； 環糊精 ； 紅外光感測器

並列摘要

Abstract

Attenuated total reflection (ATR) infrared sensing method was developed toward detection of high polarity aromatic acids. In this method, the different cavity sizes of cyclodextrins (CDs) were modified to increase the capability in detection of aromatic acids. To overcome the problem in immobilization of polar CDs to the surface of the evanescent waveguide, and high stability in aqueous solution was achieved. Selectivity for CD immobilized sensor was detected for aromatic compounds with different functional groups. Results indicated that this type of sensor provided high selectivity in detection of aromatic acids. To facilitate the use for this method to quantitatively analyses of aromatic acids in aqueous solution, the analytical functions were theoretical considered. Factors that influenced the IR signals were also studied including the effect of detection time, CD loadings, the pH values, and concentrations. The detection limits for aromatic acids at two minutes of detection time can be lower than 100 ppb but the dynamic range in detection was around two orders of magnitude only.

To conduct the behavior of the formation of inclusion complexes of analytes with CD phases, the interaction behavior was theoretical considered and the kinetic data were treated with the developed theoretical equations. Results indicated that the behaviors of the interactions between guest molecules and CDs could be explained by either parallel or consecutive reaction mechanisms. Two types of complexes were observed when aromatic acids interacted with CDs. The formation of less stable complex was highly fast and the time to reach equilibrium could be shorter than few minutes. The formation of more stable complex was also observed and the speed in formation of this type of complex was relatively slow and the time to reach equilibrium could be longer. Based on the observed signals, the amount of complex in less stable form was around three times more than that of the more stable complex.

The sensitivities of immobilized cyclodextrin IR sensing devices in determination of aromatic acids were described in the study. To develop a parameter for determination of the sensitivity in detection of aromatic acids, formation constant was determined and used to correlate with the IR signals. By examination of several aromatic acids, which formation constants are available in the literature, the results indicated that formation constants of inclusion complexes of CDs could be determined in this developed method. Meanwhile, the formation constants played an important indicator for determination of aromatic acids in aqueous solutions.

並列關鍵字

Inclusion complexes ； Cyclodextrins ； IR sensor ； Aromatic acids

參考文獻

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