Enhancement of Chemiluminescence by cationic surfactant for the Oxidation of Luminol with Pottasium Iodide/Chloramine-T and Its Applications
Date Issued
2006
Date
2006
Author(s)
Chen, Sz-Chin
DOI
zh-TW
Abstract
This study applied stopped-flow spectrometry to investigate the enhancement of chemiluminescence (CL) from the oxidation of luminol with KI/Chloramine-T (CT) by cationic surfactant cetyltrimethyl-ammonium chloride (CTAC). Various factors, including pH, concentration of reagents (KI, CT, and CTAC), that affect the CL intensity were also discussed and optimized. The CL of this system increased with increasing pH and the maximum enhancement occurred at pH 10.0. The optimized condition for this CL system is 20 mM CTAC, 0.025 mM luminol, 0.025 mM KI and 0.025 mM CT at pH 10.0; the CL intensity was thereby enhanced about 80-fold. It is suggested that the negatively charged luminol, iodide and CT will all be attracted around the positively charged micelle surface. In addition, the iodine produced from the oxidation of CT and KI is hydrophobic and easily enters the micelle. The proximity of the reagents involved in the CL reaction will largely improve the overall CL efficient, leading to a dramatic enhancement in CL emission. Other cationic surfactants enhance the intensity of CL system to various extents: 70-fold for 50 mM DTAC, only 2-fold for 1 mM HPC. The results indicate that the CL enhancement is related to the size of micelle. In addition, anionic surfactant SDS and β-cyclodextrin exhibit essentially no enhancement. The antioxidants destroy the radicals involved in the CL reaction, causing a decrease in CL emission. Thereby, the CL system has been applied to determine several antioxidants such as trolox (0~19 μM), BHA (0~5 μM), BHT (0~14 μM), GSH (0~16 μM), ascorbic acid (0~30 μM), cysteine (0~14 μM), tyrosine(0~50μM), and flavonoids (3,6-dihydroxyflavone:0~20 μM ; 3,7-dihydroxyflavone:0~50
μM).
Subjects
化學發光
chemiluminescence
Type
thesis
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