Luminol, electrochemiluminescence

A new cholesterol flow injection analysis biosensor has also been described as an application of the H2O2 ECL sensor56. In that work, the luminol electrochemiluminescence, previously studied in aqueous media, was implemented in Veronal buffer added of 0.3% triton X-100 (v/v), 0.3% PEG and 0.4% cholate to enable the solubilisation of the cholesterol and then its efficient oxidation catalyzed by the immobilized cholesterol oxidase. The ECL reaction occurred thus in a micellar medium and the performances of the H2O2 ECL sensor were investigated. 

Marquette C.A., Blum L.J., Luminol electrochemiluminescence-based fibre optic biosensors for flow injection analysis of glucose and lactate in natural samples, Anal. 

Leca B, Blum LJ (2000) Luminol electrochemiluminescence with screen-printed electrodes for low-cost disposable oxidase-based optical sensors. Analyst 125(5) 789-791... 

Zhu L, Li YX, Zhu GY (2002) A novel flow through optical fiber biosensor for glucose based on luminol electrochemiluminescence. Sens Actuators, B 86(2-3) 209-214. doi 10.1016/s0925-4005(02)00173-9... 

Marquette CA, Ravaud S, Blum LJ (2000) Luminol electrochemiluminescence-based biosensor for total cholesterol determination in natural samples. Anal Lett 33(9) 1779-1796. doi 10.1080/00032710008543158... 

The electropolymerization of MN4-MC catalysts on carbon supports is another possibility concerning the fabrication of modified electrodes. Qiu et al. [54] reported the development of a glucose biosensor based on poly-Ni-Pc/MWCNTs. The enzyme glucose oxidase (GOx) was also immobilized on the surface of the functionalized electrode. The sensor gready improved the emission of luminol electrochemiluminescence (ECL) in the presence of H2O2, one of the products of glucose oxidation by GOx. 

The chemiluminescence and electrochemiluminescence of luminol have been also exploited for the development of enzyme, DNA and immuno-biochips. Different approaches were studied in our laboratory, in which... 

This new material was used to design biochips based on the electrochemiluminescence reaction of luminol in the presence of enzymatically... 

The chapter has been structured into several sections first, there is a brief introduction, including a description of the concept and general principles of CL and how it is used in the field of explosives. The second section describes CL applications in the field of explosives and focuses in particular on the thermal energy analyser (TEA) because of its important role in the trace detection of explosives. The recent applications of luminol CL and electrochemiluminescence (ECL) to explosive detection are also described. Finally, because much of the research into explosive detectors has been directed towards civilian safety, a third section describes how CL is used as a security measure to detect explosives. 

A fiber-optic electrode was fabricated for the simultaneous generation and transmission of electrochemical luminescence by preparing a transparent electrode on the optical and surface of a fiber-optic. The opto-electrochemical properties of the micro-optical device were characterized in solutions containing the compounds required for luminol luminescence. The validity of sensitive measurement of electrochemiluminescence to be employed in a homogeneous immunoassay was evaluated by using potential step excitation of luminol in the presence and in the absence of hydrogen peroxide. 

In order to improve the sensitivity of the homogeneous immunoassay we have developed a Gber-optic electrode for the efficient generation and transmission of photons, and we have exploited luminol which has a much higher quantum efficiency than pyrene as a candidate for an electrochemiluminescent probe. 

We report here the performance characteristics of the fiber-optic electrode by app iqg the device to the electrochemiluminescence of luminol to clarify the feasibility of luminol as an electrochemiluminescent label for a sensitive homogeneous immunoassay. 

The interval of a step-wise potential application for the excitation of luminol was also investigated. Figure 7 shows that a duration of the negative potential application of 5 s and that of the positive potential application of 15 s was the best conation for the greatest luminescence generation. Under the optimum condition, electrochemiluminescence of luminol was detected with the fiber-optic electrode in the concentration range from 10 to 10 3 M as shown in Figure 8. 

Electrochemistry can be coupled with other physical methods such as fluorescence spectroscopy. An XO-based electrochemiluminescent biosensor for hypoxanthine has been reported. The enzyme was immobilized in a carbon paste electrode with bovine serum albumin cross-linked with glutar-aldehyde. The working principle of the biosensor is illustrated in Scheme 5.6. As already shown (eqn (5.3a)), H2O2 is produced by the catalytic reaction between hypoxanthine and XO immobilized on the electrode surface. In an alkaline or neutral solution, luminol is electrochemically oxidized to a compound that reacts spontaneously with H2O2 to generate chemiluminescent luminol and the ensuing luminescence was used to quantify the amount of hypoxanthine present. 

Figure 1 Three typical electrochemiluminescent compounds (1) tris 2,2 -bipyridyl)ruthenium(ll), Ru(bpy)i+ (2) luminol and (3) 2,6-bis(A/,A/-bis carboxymethyl)aminomethyl)-4-benzoylphenol.

Ammonium Rain Luminol/chlorine Electrochemiluminescence 0.014-1.4mgr ... 

Marquette CA, Blum LJ (1998) Electrochemiluminescence of luminol fOT 2,4-D optical immunosensing in a flow injection analysis system. Sens Aetna B-Chem 51(1—3) 1(X)-106. doi 10.1016/s0925-4005(98)00175-0... 

Cui H, Xu Y, Zhang Z-F (2004) Multichannel electrochemiluminescence of luminol in neutral and alkaline aqueous solutions on a gold nanoparticle self-assembled electrode. Anal Chem 76(14) 4002 010... 

Cui H, Wang W, Duan C-F, Dong Y-P, Guo J-Z (2007) Synthesis, characterization, and electrochemiluminescence of luminol-reduced gold nanoparticles and their application in a hydrogen peroxide sensor. Chem Eur J 13(24) 6975-6984. doi 10.1002/chem.200700011... 

Wang W, Xiong T, Cui H (2008) Fluorescence and electrochemiluminescence of luminol-reduced gold nanoparticles photostability and platform effect. Langmuir 24(6) 2826-2833... 

Chen M, Wei X, Tu Y (2011) A luminol-based micro-flow-injection electrochemiluminescent system to determine reactive oxygen species. Talanta 85(3) 1304—1309. doi 10.1016/ j.talanta.2011.06.002... 

Chu H-H, Yan J-E, Tu Y-E (2010) Study on a luminol-based electrochemiluminescent sensor for label-free DNA sensing. Sensors 10(10) 9481-9492. doi 10.3390/sl01009481... 

Qiu B, Lin Z, Wang J, Chen Z, Chen J, Chen G (2009) An electrochemiluminescent biosensor for glucose based on the electrochemiluminescence of luminol on the nafion/ glucose oxidase/poly(nickel(ll)tetrasulfophthalocyanine)/multi-walled carbon nanotubes modified electrode. Talanta 78(l) 76-80. doi 10.1016/j.talanta.2008.10.067... 

In 2006, first time a heated electrode was used to improve the efficiency of an electrochemiluminescent detection system [63]. The Ru(bpy)3 -ECL and Ru (bpy)3 -oxalate-ECL systems were used together with a directly heated 25 pm platinum wire electrode. The detection limit of oxalate was found to be decreased by two orders of magnitude if the temperature was increased from 22 °C to 80 °C. The authors emphasise the advantage that temperature is acting at the place where it is necessary, but leaves the dissolved sensitive constiments unaffected. An overview on the system is given in Fig. 6.15. The system was used also for electroluminescence studies with luminol [64] and with lucigenin [65]. In both applications. 

Cui H, Zou GZ, Lin XQ (2003) Electrochemiluminescence of luminol in alkaline solution at a paraffin-impregnated graphite electrode. Anal Chem 75 324-331... 

Rong J, Chi Y, Zhang Y, Chen L, Chen G (2010) Enhanced electrochemiluminescence of luminol-O, system at eold-hydrophobic ionic liquidwater interface. Electrochem Commun 12(2) 270-273... 

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