Enhancement of Chemiluminescence of the Lumino-Mn(II)-KIO4 System by Ni(II) and Its Applications
Date Issued
2011
Date
2011
Author(s)
Hsiao, Wen-Yang
Abstract
Chemiluminescence (CL) is produced by the exothermic reaction. We have studied the enhancement in CL for luminol - KIO4 - Mn2+ system caused by nickel (II) ion using flow injection analysis. About 2-fold increase in CL intensity was observed upon addition of 400 μM Ni2+ to the CL system at pH 13.0. The effects of pH, concentrations of reagents (luminol, Mn2+, Ni2+, KIO4) were optimized. In CL emission spectrum, the CL maximum signal occurred at 425 nm, indicating that the CL is caused by luminol in luminol - KIO4 - Mn2+ - Ni2+ system.
In order to know the mechanism of the chemiluminescence of luminol - KIO4 - Mn2+ - Ni2+ system, we tested a series of free radical scanvengers for their effect on CL emission. In the presence of 1O2, O2‧－and OH˙ scanvengers like DMF, ascorbic acid, DMSO, the CL emission was inhibited. In addition, deoxydenation of sample solutions by purging with nitrogen reduced the CL intensity by 80 %, indicating that oxygen is involved in this CL reaction. The CL-enhancement may result from the reaction of KIO4 and dissolved oxygen in strong alkaline solution to produce reactive oxygen species (ROS) in the prescence of catalytic Mn2+, Ni2+. Radical scavengers inhibited CL emission by their ability to destroy ROS. Experiments also found that when Ni2+ was injected into the mixture of the luminol - Mn2+ - potassium periodate reaction, chemiluminescence signals were produced once again. This phenomenon has been named as post-chemiluminescence (PCL). It was proposed that the intermediate (X) formed during the luminol - Mn2+ - potassium periodate reaction was excited to X* under the action of Ni2+, then the energy of X* was transferred to 3-AP, and 3-AP* emits light at 425 nm.
By using the CL system, we tested 45 compounds including amino acids, vitamins, antioxidant for their effect on the CL emission. We found that common antioxidants such as catecholamines and benzenediols showed inhibiting effect on our CL system, The CL-inhibition may result from scanvenging ROS by antioxidants. Finally we did a series of optimization for the best inhibitory effect of hydroquinone, the detection limits for hydroquinone was 8.9×10-11 mol L-1.
Subjects
chemiluminescnece
flow injection analysis
potassium periodate
nickel (II) ion
post-chemiluminescence
benzenediol
Type
thesis
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