有机化合物对Luminol-KIO4-H2O2体系化学发光的抑制和增强

研究了36种有机化合物对鲁米诺-高碘酸钾-过氧化氢(luminol-KIO₄-H₂O₂)体系化学发光的影响,发现其大部分能抑制或增强体系化学发光强度,并且抑制或增强化学发光强度的能力与化学发光体系的pH值以及有机化合物分子结构中芳香环上功能基(—OH和—NH₂)的数目、位置,取代基的电子效应、空间效应等有关。讨论了化学发光强度抑制或增强的机理。基于24种有机化合物对体系化学发光的抑制或增强考察了其分析应用的可能性,发现数个化合物的检测限可达ng·mL^-1水平。

Inhibition and Enhancement of Luminol-KIO4-H2O2 Chemiluminescence by Organic Compounds

The inhibition and enhancement of liquid phase CL by organic compounds are of considerable(interests) in analytical chemistry because they can be used for the sensitive detection of numerous compounds.However,the mechanism of inhibition and enhancement is not fully understood and the discovery of new(enhancers) and inhibitors is usually achieved in an empirical fashion by trail and error.Although there are(reports) in the literatures concerning the use of the luminol-KIO₄-H₂O₂ CL for the determination of hydrogen peroxide,glucose and ascorbic acid,the effect of aromatic compounds on the luminol-KIO₄-H₂O₂ CL has not been studied systematically.The effects of 36 organic compounds on the luminol-KIO₄-H₂O₂ system chemiluminescence(CL) were studied under different pH conditions of luminol solution.The CL signal was detected with a flow injection chemiluminescence system(Xi'an Ruimai Electronic Technology Co.,Ltd.,China) consisted of a model IFFM-D peristaltic pump,a mixing tee,a model IFFS-A CL detector equipped with a glass coil(used as reaction coil and detection cell),a photomultiplier,and IBM compatible microcomputer.It was found that most of the tested compounds could inhibit or enhance the CL intensity.The activities of such(inhibitors) or enhancers were related to pH value of the CL system and the number and position of functional groups such as —OH and —NH₂ on aromatic ring and property of substituent group,electron delocalization and steric hindrance.The CL spectra and UV-visible absorption spectra were studied and the mechanism for the CL inhibition and enhancement was also discussed.The mechanism for such inhibition or enhancement of organic compounds is most likely due to the reactions between inhibitors or enhancers and radical intermediates of the CL reactions.Based on the CL inhibition or enhancement,the possibility of analytical applications was explored.The results demonstrated that numerous compounds are detectable at ng·mL^-1 level.