The SI unit is the joule.
Abstract Chemiluminescence CL is an important method for quantification and analysis of various macromolecules. A wide range of CL agents such as luminol, hydrogen peroxide, fluorescein, dioxetanes and derivatives of oxalate, and acridinium dyes are used according to their biological specificity and utility.
This review describes the application of luminol chemiluminescence LCL in forensic, biomedical, and clinical sciences. LCL is a very useful detection method due to its selectivity, simplicity, low cost, and high sensitivity.
LCL has a dynamic range of applications, including quantification and detection of macro and micromolecules such as proteins, carbohydrates, DNA, and RNA.
Luminol-based methods are used in environmental monitoring as biosensors, in the pharmaceutical industry for cellular localization and as biological tracers, and in reporter gene-based assays and several other immunoassays. Here, we also provide information about different compounds that may enhance or inhibit the LCL along with the effect of pH and concentration on LCL.
This review covers most of the significant information related to the applications of luminol in different fields. Luminol, Chemiluminescence, Electrochemiluminescence, Cellular localization, Reporter gene assay, Forensic science Introduction Luminol 5-amino-2,3-dihydro-1,4-phthalazinedione is a yellow-colored crystalline solid powder and soluble in most polar organic solvents, but insoluble in water [ 1 ].
Luminol is a diprotic acid denoted as LH2 with pKa values of 6. These two pKa values correspond to the loss of two acylhydrazide protons at pKa1 and pKa2respectively [ 2 — 4 ].
Luminol solutions are highly sensitive to light and incompatible with strong oxidizing agents, strong acids, strong bases, and strong reducing agents [ 1 ].
Luminol solutions are thermally unstable; therefore, they should be protected from high temperatures [ 5 ].
Luminescence-based methods are widely accepted to study the biological system [ 6 — 11 ]. Luminol is one of the most widely used chemiluminescent compounds because of its availability and low cost. Luminol can also be oxidized by other oxidizing agents in the presence of catalysts, such as horseradish peroxidase, lactoperoxidase and myeloperoxidase, etc.
Hydrogen peroxide is the most significant oxidizing agent, which increases the luminescent intensity of luminol.
Strong alkaline conditions may cause protein denaturation. Therefore, peroxidases are usually preferred because luminol can be oxidized in mild conditions. However, myeloperoxidase can be used to carry out the oxidation of luminol at high pH 10—13 [ 1516 ].
This CL system has been employed in the detection of antioxidants [ 17 ]. The CL property of luminol was first discovered by Albrecht in [ 18 ].
Since then, the luminescent properties of luminol have been extensively explored. Luminol exists in two isomers Fig 1. Isomer I is more stable, exhibits CL in the presence of oxidizing agents, and also has fluorescence properties. However, isomer II neither exhibits CL nor fluorescence [ 19 ].Luminol and isoluminol are the most investigated chemiluminescent compounds,, and their wide use in various sensitive analyses has been reviewed,,,.
The 3-aminophthalate anion of luminol . Sigma-Aldrich Online Catalog Product List: Chemiluminescent compounds. Compounds that generate or enhance LCL are divided into three major categories: (1) compounds showing a catalytic true peroxidase or peroxidase-like activity, (2) compounds with a high oxidizing capacity towards luminol and (3) compounds with a complex chemical composition with an undefined action (Fig 3).
The first group includes .
Compounds that generate or enhance LCL are divided into three major categories: (1) compounds showing a catalytic true peroxidase or peroxidase-like activity, (2) compounds with a high oxidizing capacity towards luminol and (3) compounds with a complex chemical composition with an undefined action (Fig 3).
The first group includes inorganic or bioinorganic species that are a major source of .
Luminol chemiluminescence can also be triggered by a number of substances such as copper or copper-containing chemical compounds, and certain bleaches. As a result, if someone cleans a crime scene thoroughly with a bleach solution, residual cleaner makes the entire crime scene produce the typical blue glow, which effectively camouflages organic evidence such as blood.
The peroxyoxalate chemiluminescence offers a lot of didactic possibilities. A broad selection of chemical laws and rules can be easily demonstrated with this reaction – for example phase transfer phenomena, dependence of reaction rate on stirring rate, temperature, presence of catalysts, inhibitors, etc.