Luminol emission maxima

The anthracene derivative (44), naphtho-[2,3-g]-phthalazine-l,4-dione (NPD) is fairly stable, and it chemiluminesces on oxidation with basic hydrogen peroxide with an emission maximum of 430 nm, similar to the luminol emission maximum [43, 56, 57]. 

Several other chromophores have been used in the development of sensors based upon ECL. For example, the luminol reaction is a conventional chemi-luminence reaction that has been studied in detail and it is believed that the mechanism of the ECL reaction is similar, if not identical, to that of the chemiluminescence. As shown in Fig. 2, the luminol ion undergoes a one-electron oxidation to yield a diazaquinone, which then reacts with peroxide or superoxide ( OOH) to give the excited 3-aminophthalate which has an emission maximum of 425 nm. This reaction is particularly versatile and has been utilized in a variety of ECL assays, many of which have been previously summarized by Knight [1], The luminol ECL reaction can be used for the determination of any species labeled with luminol derivatives, hydrogen peroxide, and other peroxides or enzymatic reactions that produce peroxides. A couple of examples are described later. 

Nevertheless, (23) chemiluminesces with an efficiency of ca. 2% of that of luminol in the aqueous - alkaline H2O2 - hemin system. TTie emission maximum was found to be 390 nm which corresponds to the fluorescence of paracyclophane-2,3-dicarboxylate [39, 40]. Thus in this the simplest member of the series a composite fluorescer is produced. The same observations can be made concerning the corresponding naphthalene analogue (24). 

The maximum of luminol chemiluminescence emission is at 425 nm in aqueous and at 480 nm in DMSO-containing solvent. It was suggested that different anions of 3-aminophthalate were responsible for this phenomenon, namely 51 (in water) and 52 (in aprotic solvents). 

CL emission. The system allows a simple determination of phosphate in 3 min with a linear range of 4.8-160 pM. Owing to its sensitivity, this method could be satisfactorily applied to the analysis of maximum permissible phosphate concentrations in natural waters [42-44], Also, the maltose-phosphorylase, mutar-ose, and glucose oxidase (MP-MUT-GOD) reaction system combined with an ARP-luminol reaction system has been used in a highly sensitive CL-FIA sensor [45], In this system, MP-MUT-GOD is immobilized on A-hydroxysuccinimide beads and packed in a column. A linear range of 10 nM-30 pM and a measuring time of 3 min were provided, yielding a limit of detection of 1.0 pM as well as a satisfactory application in the analysis of river water. 

The oxidative reactions of luminol and isoluminol derivatives at high pH result in the formation of 3-aminophthalate or 4-aminophthalate and nitrogen via an electronically excited state. The transition from the excited to the ground state induces the emission of light having a wavelength maximum of 425 nm. Quantitation is possible at picomolar or even attomolar levels of the aminophthalhydrazide. 

Firstly, in order to obtain an understanding of the mechanism of the sensitized luminol-based CL reaction, the CL emission spectrum was obtained with a F-4500 fluorescence spectrophotometer. The results showed the maximum emission wavelength in the presence of ofloxacin was the same as that in the absence of ofloxacin and the maximum light emission was at about 425 nm. The emitter was 3-aminophthalate, the oxidation product of luminol. 

In the present technique, organo-nitrate compounds are first trapped into a collection tube that contains a proprietary sampling material. The desorbed material is then catalytically converted to NO2 upon exposure to pulse heated platinum wire. Chemiluminescence is then produced by the reaction of NO2 with luminol. The detection system uses a gas-liquid reaction leading to light emission with a maximum at 425 nm. This wavelength corresponds to the maximum sensitivity for most photomultiplier tubes. The biggest problem... 

However only one of the compounds of this type has as yet reached the efficiency of luminol, although the first representative of this series, pyromellitic hydrazide (7), described as early as 1937 [21], exhibits a rather strong yellow chemiluminescence. The maximum emission was found to be at 540 nm in a... 

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