2: Chemiluminescence Reagents
- Page ID
- 76108
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)- 2.1: Luminol
- Luminol is the common name for 5-amino-2,3-dihydro-1,4-phthalazinedione (often called 3-aminopthalhydrazide). Oxidation of luminol produces excited 3-aminophthalate, which on relaxation emits light (λmax = 425 nm) with quantum yield of 1%. Alternatively, luminol chemiluminescence may be triggered electrochemically.
- 2.2: Lophine and pyrogallol
- Lophine and pyrogallol are the earliest-known chemiluminescence reagents. Lophine exhibits lemon yellow chemiluminescence in solution and is one of the few long-lasting chemiluminescent molecules. It forms dimers that have piezochromic and photochromic properties. It has been proposed as an analytical reagent for trace metal ion detection.
- 2.3: Luciferins
- Luciferases are enzymes that catalyse light-emitting reactions in living organisms - bioluminescence. They occur in several species of firefly and in many species of bacterium. Firefly Luciferases are extracted by differential centrifugation and purified by gel filtration. Luciferins are substrates of luciferases . Firefly luciferin emits at 562 nm on reaction with oxygen, catalysed by luciferase in the presence of adenosine triphosphate (ATP) and magnesium ions.
- 2.4: Lucigenin and coelenterazine
- Lucigenin is used in a wide variety of assays, especially those involving enzymatic production of hydrogen peroxide, and as a label in immunoassays. It reacts with various reductants, including those present in normal human blood[2], such as glutathione, uric acid, glucuronic acid, creatinine, ascorbic acid and creatine. The chemiluminescence intensity for a mixture of these analytes is equal to the sum of the intensities, measured separately for each analyte present.
- 2.5: Dioxetanes and oxalates
- Peroxy-oxalate chemiluminescence (PO-CL) was first reported in 1963 as a very weak bluish-white emission from oxalyl chloride, Cl-CO.CO-Cl, on oxidation by hydrogen peroxide; a similar blue emission occurs from related oxalyl peroxides. Much more intense emission is obtained in the reaction between aryl oxalates and hydrogen peroxide in the presence of a fluorophore; it is this version of the reaction that is analytically useful.
- 2.7: Manganese
- Manganese (VII) in the form of potassium permanganate has been used as a chemiluminescence reagent for several decades. A broad band of red light is emitted on reaction with over 270 compounds in acidic solution. Among the organic analytes are morphine and a wide range of other pharmaceuticals, phenolic substances, amines and hydrazines in addition to well-known reductants such as ascorbic acid and uric acid
- 2.8: Cerium
- Cerium(IV)-based chemiluminescence systems involve the reduction of cerium(IV), which suggests that the emitter is a cerium(III) species. The chemiluminescence reaction is carried out in an acidic medium (generally sulfuric acid) and has been applied for the determination of substances of biological interest.
- 2.9: Ruthenium
- The chemiluminescence involving tris(2,2'-bipyridyl)ruthenium(II), [Ru(bpy)3]2+, is most interesting. It involves the oxidation of [Ru(bpy)3]2+ to [Ru(bpy)3]3+, which is followed by reduction with an analyte species to produce an emission of light.
Thumbnail: Chemiluminescence after a reaction of hydrogen peroxide and luminol. This is an image from video youtu.be/8_82cNtZSQE. (CC BY-SA 4.0; Tavo Romann).