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Spectroscopic analysis
Published in John P. Dakin, Robert G. W. Brown, Handbook of Optoelectronics, 2017
Günter Gauglitz, John P. Dakin
A compound commonly used to produce green light is called luminol (C8H7N3O2), which is known by several other chemical names, including 5-amino-2,3-dihydro-1,4-phthalazine-dione. When luminol is added to a basic solution of oxidizing compounds, such as perborate, permanganate, hyperchlorite, iodine, or hydrogen peroxide, in the presence of a metallic-ion catalyst, such as iron, manganese, copper, nickel, or cobalt, it undergoes an oxidation reaction to produce excited electronic states, which decay to give green light. The strongest response is usually seen with hydrogen peroxide, but very low concentrations of oxidizing agents such as ozone, chlorine, and nitrogen dioxide can also be measured. Numerous biochemicals can also cause a light-emitting reaction and hence be detected.
Light Sources
Published in Toru Yoshizawa, Handbook of Optical Metrology, 2015
Luminol in an alkaline solution with hydrogen peroxide (H2O2) in the presence of a suitable catalyst (iron or copper, or an auxiliary oxidant) produces chemiluminescence. The energy released in the reaction is sufficient to populate the excited state of the reaction product 3-aminophthalate (3-APA*), which de-excites to 3-APA emitting a photon. In the ideal case, the number of the emitted photons should correspond to the number of molecules of the reactant. However, the actual quantum efficiency of nonenzymatic reactions, as in this case, seldom exceeds 1%. The luminal reaction is an example of liquid-phase reaction [78,79].
Determination of the antibiotic minocycline by integrated optofluidic microstructured polymer optical fiber chemiluminescence
Published in Instrumentation Science & Technology, 2021
Zhanao Li, Xinghua Yang, Pingping Teng, Depeng Kong, Shuai Gao, Zhihai Liu, Jun Yang, Danheng Gao, Meng Luo, Xingyue Wen, Libo Yuan, Kang Li, Mark Bowkett, Nigel Copner
Next, since K3Fe(CN)6 is involved in the reaction as a reagent, its concentration also has an important effect on the chemiluminescence. The influence of K3Fe(CN)6 concentration on the luminol-K3Fe(CN)6 system in the concentration from 0.001 to 0.1 M is shown in Figure 5a. At concentrations from 0.001 to 0.005 M, the response increased. When the concentration exceeds 0.005 M, the intensity decreased. Figure 5b shows the optimal K3Fe(CN)6 concentration was 0.005 M after the addition of MC to the reaction system. The chemiluminescence of luminol is a complex oxidation involving multiple reversible reactions. In this case, the high concentration of K3Fe(CN)6 may inhibit one step in the oxidation of luminol, reducing the chemiluminescence. Moreover, the K3Fe(CN)6 is not colorless, which may affect the collection of the signal light. A concentration of 0.005 M K3Fe(CN)6 was employed in subsequent measurements.
Carbon dots-enhanced luminol chemiluminescence and its application to 2-methoxyestradiol determination
Published in Green Chemistry Letters and Reviews, 2018
Min Zhang, Yulei Jia, Jianhua Cao, Guanghui Li, Huacheng Ren, Hui Li, Hanchun Yao
2-ME (Zhengzhou University, China) stock solution (5.0 × 10−4 g mL-1) was prepared by dissolving 50.05 mg 2-ME in 100 mL of methanol and working solutions were prepared by diluting with water as required. Luminol (Solarbio, China) stock solution (1.0 × 10−2 mol L-1) was prepared by dissolving 0.1772 g luminol in 100 mL of 0.1 mol L-1 NaOH and stored in the refrigerator at 4°C. The working solution of luminol was prepared by gradually diluting stock solution with 0.1 mol L-1 NaOH solution. K3Fe(CN)6 (Kermel Chemical Reagent Co., Ltd, Tianjin, China) stock solution (5.0 × 10−3 mol L-1) was prepared by dissolving 82.3 mg K3Fe(CN)6 in 50 mL ultra pure water and stored in the dark. Fresh solutions were prepared daily.