Catalysts lucigenin

The oxidation reactions of luminol and lucigenin can be used to assay for H Oj. For example, analysis of glucose in biological systems can be achieved using a three-enzyme system of mutarotase, glucose oxidase and horseradish peroxidase by correlation with the amount of HjOj released. Similarly, cholesterol can be measured using cholesterol oxidase. The fact that the rate of luminol oxidation depends on the concentration of the catalyst can be used as a method for determination of Co +, Fe +, Cr + and Mn + and other catalysts.Some examples of the use of luminol, isolumi-nol and their derivatives in immunoassays are shown in Table 3.11. ... 

While luminol and isoluminol require an oxidant plus a catalyst for initiation of the chemiluminescent reaction, esters derived from A -methyl acridinium carboxylic acid require only alkaline hydrogen peroxide (W4). Acridinium esters were first introduced by McCapra s group (M23, M25, S32), based on earlier work on the bioluminescence of the lucigenin/luciferase system (G18), and reviewed in McCapra and Beheshti (M21). From Fig. 19, one can see the structural similarity between lucigenin and a typical acridinium ester. 

Similar to luminol and lucigenin, both lophine and gallic acid also react with alkaline hydrogen peroxide to yield chemiluminescence. In all of these reactions, the emission intensity is proportional to transition metal ion catalyst concentration over finite ranges. Table 1 provides an abbreviated comparison of the selectivity and sensitivity available with these systems. 

CIA is similar to radioimmunoassay but, instead of radioactively labeled substrates and antibodies, chemilumeneseent probes label the substrates and antibodies and emit light in the presence of H2O2 and a catalyst such as peroxidases. CL markers are low weight molecules, chemically close to luminol and lucigenin [25]. In ICMAthe system contains labeled and unlabelled substrates (A and A, respectively) and antibodies (anti-A). Thus, a mixture of labeled and unlabeled immune complexes is made ... 

Many chemiluminescent compounds emit light only in neutral or, better in alkaline solution, e.g. luminol and lucigenin. Thus these can be used as neutralization indicators in acid-base titrations. Used in an end-point titration, light can be detected from strongly coloured or turbid or opaque solutions where colorimetric titrations are difficult. For example in the determination of the acidity of milk, of red wine, or mustard [4] or of dark coloured fats and oils [5,6]. It seems that luminol-fluorescein mixtures are better than luminol alone, because a hemin catalyst is not required here [7]. The system luminol - hemin leads to an irreversible destruction of hemin and is, therefore, not reversible with respect to the catalyst - in contrast to the luminol-fluorescein system [7]. 

Luminol-hydrogen-peroxide-catalyst [9, 10] lucigenin-hydrogen peroxide [11,12] Luminol-fluorescein-hydrogen peroxide [13] and lucigenin-fluorescein-hydrogen peroxide [14]. 

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