Pyrogallol 與 luminol 之化學發光及其應用

Abstract

本研究使用自行組裝的流動注入分析系統探討CTAC、CH3CHO 增強KIO4氧化pyrogallol及luminol的化學發光的機制。Pyrogallol之化學發光的研究結果發現：在pH 11.0於pyrogallol/KIO4/CH3CHO系統加入50 mM CTAC，化學發光的強度可增強10倍或6 % CH3CHO添加至pyrogallol/KIO4/CTAC化學發光系統，化學發光的強度可增強19倍。推測此化學發光增強的機制: 陽離子型介面活性劑CTAC係為一帶正電微胞，提供有利化學發光反應的剛性環境，本系統在pH 11.0的鹼性環境下進行反應時，pyrogallol、KIO4皆帶負電，容易聚集在帶正電的微胞表面附近，拉近分子彼此距離，增加反應機會，因而促進化學發光效率;CH3CHO可幫助溶解pyrogallol氧化時產生之聚合產物，同時它被氧化劑氧化過程中可能會產生活性含氧物質 (reactive oxygen species)，進而促使系統的發光增強。在研究中同時對pH值、流速、反應物 (pyrogallol、CTAC、CH3CHO、KIO4)的濃度與混合的方式等因素對於化學發光的強度之影響做詳細的探討與最佳化。此化學發光系統在不同pH值下，可用以檢測不同物質，如抗氧化劑trolox，尿酸，多酚類化合物，發光劑luminol等。因抗氧化劑會消滅化學發光所產生的自由基，而造成化學發光的效率降低，其偵測範圍與不同的抗氧化劑的抗氧化能力有關。 在以luminol為主的化學發光系統中，於0.5 mM luminol-5 mM KIO4反應中加入1 mM pyrogallol、2 % CH3CHO及30

We have studied the enhancement in chemiluminescence (CL) for the oxidation of pyrogallol and luminol with potassium periodate caused by CTAC and acetaldehyde using a home-made flow injection analysis system. For the pyrogallol CL, a 10-fold increase in CL intensity was observed upon addition of 50 mM CTAC and a 19-fold increase in CL intensity was observed upon addition of 6 % acetaldehyde to the CL system at pH 11.0. The CL-enhancement may result from the increases in the overall CL efficiency and the fluorescence quantum yield from the production of excited singlet oxygen. The effects of pH, flow rate, concentrations of reagents (pyrogallol、acetaldehyde、CTAC、KIO4), and modes of reagent mixing on CL emission were also investigated and optimized. The CL system has been applied to the determination of trolox, polyhydroxyl compounds, uric acid, luminol, etc. The antioxidants destroy the radicals involved in the CL reaction, causing a decrease in CL emission. The dynamic ranges vary for different antioxidants with different antioxidative power. In addition, we have also studied the luminal-based CL system. For the luminol CL, a 80-fold increase in CL intensity was observed upon addition of 2 % acetaldehyde, 1 mM pyrogallol, and 30