Chemiluminescence, production

Isoprene, the most abundant hydrocarbon emitted to the atmosphere by plants, can also be measured using ozone chemiluminescence. As discussed above, al-kenes react with ozone to produce formaldehyde in its A2 electronic state, in addition to several other chemiluminescent products. In a fast isoprene detector manufactured by Hills Scientific (Boulder, CO), the chemiluminescence is detected using a blue-sensitive PMT to maximize the sensitivity for isoprene detec-... 

Colorimetric assays are commonly used in molecular biology and biotechnology laboratories for determining protein concentrations because the procedures and their instrumentation requirements are simple. Two forms of assays are used. The first involves reactions between the protein and a suitable chemical to yield a colored, fluorescent, or chemiluminescence product. Second, a colored dye is bound to the protein and the absorbance shift is observed. Disadvantages of both these methods include limited sensitivity at below 1 pg/mL, interferences from buffers, and unstable chromophores (Jain et al. 1992). 

Scheme 4.93 Reaction scheme of the oxidation ofluminol to the chemiluminescent product 2-aminophthalate [405].

Results indicate a quantum yield of near unity 193 nm photolysis of CH3NO2, n-C3H7N02, and 498 C6H5NO2. Chemiluminescent products monitored. Relation to explosion chemistry discussed... 

Glow. Chemiluminescent products formed in surface-assisted reactions involving atomic oxygen are believed to be a source of space vehicle glow, which may seriously interfere with the function of sensitive optical instruments designed to detect low light levels. The most widely accepted... 

Absorption of the Ca-HCl complex at different frequencies can be linked with different regions of the potential energy surface and the resulting branching to the different product states is noticeably different. The yield of chemiluminescent products is only important for excitation of certain regions of the potential surface that cross at reasonable distance from the equilibrium with a potential surface correlating with an excited ion core Ca+ D. Also, it can be expected that the decay of the initially excited state in the case of the local excitation of the calcium and in the latter case of the direct excitation of the charge-transfer potential have different appearances. 

It should be noted that the relationship between the final signal output and concentration of the analyte (dose-response) may be one of direct or inverse proportionality, and is dependent on the specific assay format. In addition, a number of different reporter enzymes may be used (e.g., horseradish peroxidase, alkaline phosphatase, p-galactosidase), along with a number of different signaling systems (e.g., substrates that yield chromogenic or fluorescent or chemiluminescent products, activation of signaling enzymes, amplification by biotin-avidin system or polymerase chain reaction). 

The Ca + HCI reaction on the ground potential surface (i.e., Ca( So) atoms) is 3200 cm endothermic for the production of CaCl(X L) + H. However, reactions of excited Ca atoms ( P, D, P, D) with HCI have been studied by several groups in beam-gas experiments [195]. Such reactions, e.g., promoted by the 422.7 nm Ca P, - Sq transition, yield chemiluminescent products with large reaction cross-sections... 

Signal antibodies have most often been radiolabeled (for immunoradiometric assays [IRMA]) with ( 25j) 7,62,i%,344,4i4 labeled with a chemiluminescent (for immunochemilummo-metric assays [ICMA]) compound, such as acridinium ester, or an enzyme (enzyme-linked immunosorbent assay [ELISA] or enzyme immunoassay [EIA]), such as ALP, converting a substrate (1,2-dioxetane phosphate) to a chemiluminescent product. 

Two chemiluminescent products, MO and MCI, are observed from the reactions M + CIO2 [350]. The product MCI is especially surprising because of high degree of bond rearrangement required in the collision to form MCI and O2 as products. The MO product is formed almost exclusively in the long-lived state with vibrational population... 

Dynamic methods have been proposed for carrying out online UV spectrometric procedures to determine active ingredients such as UV filters in sunscreens, based either on selective SPE of the analytes or on derivatization reactions to obtain colored or chemiluminescent products. Figure 5 shows two flow systems used to determine benzophenone-3 in sunscreens without matrix interferences by reaction with Ni(II) in ammoniacal medium. 

Notice, for example, how the red component observed in the gas-phase spectrum has also disappeared in that of the cluster-supported case. On the other hand, the cluster spectrum exhibits as dominant feature a continuum, which is not present in the gas-phase chemiluminescence. These studies lead to the conclusion that BaClj is the only chemiluminescent product. Thus, the chemiluminescent reaction Ba + CI2 BaClj, closed under gas-phase collision conditions, mrns out to be possible in fact, it... 

Aluminium salts stimulated luminol-enhanced chemiluminescence production by human neutrophils (Stankovic and Mitrovic 1991). Kong et al. (1992) described an Al(lll) complex with O which was a stronger oxidant than 02 " itself and which may contribute to the adverse biological effects of Al(III). Aluminium can enhance hydroxyl radical production by iron, but it is not in itself capable of catalysing the generation of hydroxyl radical fi-om the Fenton or Haber-Weiss reactions (Gutteridge et al. 1985). Aluminium fadhtation of iron-mediated Upid peroxidation is dependent on substrate, pH (greater at pH 5.5 than 7.4), and alumi-... 

Van der Nat JM, Van der Sluis WG, t Hart LA, Van Dijk H, de Silva KT, Labadie RP (1991) Activity-guided isolation and identification of Azadirachta indica bark extract constituents which specifically inhibit chemiluminescence production by activated human polymorphonuclear leukocytes. Planta Med 57(1) 65-68... 

Polarization of chemiluminescent products from oriented reagent has been addressed by Prisant et al, [25] using the DIPR-DIP model. As discussed in detail elsewhere [4], the electron-jump model fails to account for the enhanced reactivity of vibrationaUy excited N2O. Nevertheless, the general trends predicted by Prisant et at. are confirmed in our data. "CoUinear" approaches are predicted to result in higher product polarization than "side-on" approaches in accord with our observations. 

Rotational alignmpnt of the chemiluminescent products is manifested by the polarisation of their fluorescence, since the transition dipole pf is referenced to the molecular rotation axis (at the high J limit). For "paraller transitions, P, Rt-, pf j. J and for "perpendicular" transitions, Qj-, pf n J. Alignment of J with respect to the reagent relative velocity k is reflected in an accompanying spontaneous fluorescence polarisation, where... 

Heterocycles similar to compound ii are responsible for the chemiluminescence produced by a number of species [e.g., fireflies (see Real Life 9-1) and several deep-sea fish] they also serve as the energy sources in commercial chemiluminescent products. 

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