Oxidation chemiluminescence analysis

Chemiluminescence. Chemiluminescence (262—265) is the emission of light duting an exothermic chemical reaction, generaUy as fluorescence. It often occurs ia oxidation processes, and enzyme-mediated bioluminescence has important analytical appHcations (241,262). Chemiluminescence analysis is highly specific and can reach ppb detection limits with relatively simple iastmmentation. Nitric oxide has been so analyzed from reaction with ozone (266—268), and ozone can be detected by the emission at 585 nm from reaction with ethylene. 

The verification of theoretical data obtained by simulation of peroxide oxidation kinetics of macromolecules with experimental data, obtained from chemiluminescent analysis of blood using automated complex ChLC-1. This automated complex was developed by the authors and laboratory colleagues. 

CHEMILUMINESCENT ANALYSIS BASED ON THE LUMINOL OXIDATION REACTION IN SPECIFIC REGIMES... 

Imaging chemiluminescence technique. Chemiluminescence analysis is suitable for studying the early stages of the thermal oxidation of rubbers. A weak emission of light formed by chemical reactions appears during the oxidative degradation of hydrocarbons. This technique can be used to depth profile the oxidation of rubbers. MR... 

Chemiluminescent analysis of accumulation of lipid hydroperoxides during Fe-induced oxidation of human plasma lipoproteins showed that different CRC possess nonequal protecting activity. The following rank of increased protection was found (at 5 mM concentration of each CRC) N-acetylcamosine (13%) < N-acetylanserine (29%) < homocamosine (60%) < ophidine (62%) < carnosine (74%) < anserine (97%). Thus, change... 

Sample Chemiluminescence Analysis Induction time Oxidation rate (relative units)(relative units) Oven life (days)... 

Differentiation assay. Chemiluminescence analysis showed that all monomers induced a comeback of oxidative burst in HL-60 cells. This differentiating effect is present at 55 x 10 3 mmol/L UDMA and 0.4 mmol/L BDDMA (Fig. 2)., i.e. at the same concentrations at which the monomers increase cell mortality (as above). 

Jenkins, R.A. and B.E. GUI Procedure for the determination of nitric oxide and nitrogen dioxide in cigarette smoke by chemiluminescent analysis 32nd Tobacco Chemists Research Conference, Program Booklet and Abstracts, Vol. 32, Paper No. 35, 1978, p. 19 Determination of oxides of nitrogen (NO,.) in cigarette smoke by chemiluminescent analysis Anal. Chem. 52 (1978) 925-928. 

The reaction process is considered to be the same for similar compounds, but the sensitivity of chemiluminescence has been suggested to be structure-dependent. The reactivity of a compound contributes to its sensitivity. Phenacylalcohol derivatives have been detected with different sensitivities in chemiluminescence analysis.In radical reactions, the reaction proceeds as follows in buffered solutions, a compound such as phenacylalcohol is easily attacked by oxidation if traces of a copper or iron salt are present, and the superoxide reacts with luminol or lueigenin to produce chemiluminescence as shown in Figure 11.7. 

In the second series of experiments, the products from the photo-oxidation of diethyl ether, carried out in a Teflon bag reactor at ppm and ppb levels, have been determined by withdrawing vapour samples and monitoring by gas chromatography, HPLC and by chemiluminescence analysis. The major reaction products which have been measured are ethyl formate, ethyl acetate, acetaldehyde, formaldehyde, PAN, methyl nitrate and ethyl nitrate. The products observed arise from the decomposition reactions of the 1-ethoxyethoxy radical and from its reaction with oxygen. The data enable the establishment of a quantitative mechanism for the photo-oxidative reaction. In addition the rate of conversion of NO to NO2, determined by chemiluminescence analysis, shows that for each molecule of ether reacted only one molecule of NO is converted to NO2. In further end-product analyses experiments, the OH radical initiated photo-oxidation of n-hexane or the photolyses of 2- or 3-hexyl nitrites were studied to examine the... 

Polyvinyl alcohol oxidation affected by hydrogen peroxide in the presence of ferrous sulfate (II) in aqueous solutions is accompanied by chemiluminescence in the visible spectrum (Fig. 23.6). In Fig. 23.6, it is seen that luminous intensity passes through a maximum. This facts shows that luminescence emitter is an intermediate product of liquid-phase PVA oxidation. The analysis of the kinetic curve of chemiluminescence intensity showed that its initial part is well linearized (Fig. 23.6, the correlation index r = 0.998) in the equation coordinates... 

Celina, M., George, G. A. A heterogeneous model for the thermal oxidation of solid polypropylene from chemiluminescence analysis. Polymer Degradation and Stability, 40 (1993), p. 223 - 336... 

The techniques most commonly used in thermo-oxidative studies on polymers are mainly based on thermal analysis methods such as thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) and on pyrolysis-gas chromatographic studies (particularly if they are linked to complimentary techniques such as mass spectrometry or infrared spectroscopy). Other techniques that have been used to a much lesser extent include chemiluminescence analysis, nuclear magnetic resonance (NMR) spectroscopy, electron spin resonance, and positron annihilation lifetime mass spectrometry. 

Antioxidants have been shown to improve oxidative stabiHty substantially (36,37). The use of mbber-bound stabilizers to permit concentration of the additive in the mbber phase has been reported (38—40). The partitioning behavior of various conventional stabilizers between the mbber and thermoplastic phases in model ABS systems has been described and shown to correlate with solubiHty parameter values (41). Pigments can adversely affect oxidative stabiHty (32). Test methods for assessing thermal oxidative stabiHty include oxygen absorption (31,32,42), thermal analysis (43,44), oven aging (34,45,46), and chemiluminescence (47,48). 

Titration Indicators. Concentrations of arsenic(III) as low as 2 x 10 M can be measured (272) by titration with iodine, using the chemiluminescent iodine oxidation of luminol to indicate the end point. Oxidation reactions have been titrated using siloxene the appearance of chemiluminescence indicates excess oxidant. Examples include titration of thallium (277) and lead (278) with dichromate and analysis of iron(II) by titration with cerium(IV) (279). 

Ozone can be analyzed by titrimetry, direct and colorimetric spectrometry, amperometry, oxidation—reduction potential (ORP), chemiluminescence, calorimetry, thermal conductivity, and isothermal pressure change on decomposition. The last three methods ate not frequently employed. Proper measurement of ozone in water requites an awareness of its reactivity, instabiUty, volatility, and the potential effect of interfering substances. To eliminate interferences, ozone sometimes is sparged out of solution by using an inert gas for analysis in the gas phase or on reabsorption in a clean solution. Historically, the most common analytical procedure has been the iodometric method in which gaseous ozone is absorbed by aqueous KI. 

Applications of the oxalate-hydrogen peroxide chemiluminescence-based and fluorescence-based assays with NDA/CN derivatives to the analysis of amino acids and peptides are included. The sensitivity of the chemiluminescence and fluorescence methods is compared for several analytes. In general, peroxyoxalate chemiluminescence-based methods are 10 to 100 times more sensitive than their fluorescence-based counterparts. The chief limitation of chemiluminescence is that chemical excitation of the fluorophore apparently depends on its structure and oxidation potential. 

Comparison of chemiluminescence isothermal runs with oxygen uptake and DSC measurements has been at the centre of interest since practical industrial applications of the chemiluminescence method were attempted. It is a fact that the best comparison may be achieved when studying polymers that give a distinct induction time of oxidation typical for autoaccelerating curves of a stepwise developing oxidation. This is the particular case of polyolefins, polydienes and polyamides. The theoretical justification for the search of a mutual relationship between the oxidation runs found by the various methods follows directly from the kinetic analysis of the Bolland-Gee scheme of polymer oxidation. 

J.K. Robinson, MJ. Bollinger, and J.W. Birks, Luminol/H202 chemiluminescence detector for the analysis of nitric oxide in exhaled breath. Anal. Chem. 71, 5131-5136 (1999). 

Chemiluminescent techniques have been used to determine nanomolar quantities of nitrate and nitrite in seawater [124,125]. This method depends on the selective reduction of these species to nitric oxide, which is then determined by its chemiluminescent reaction with ozone, using a commercial nitrogen oxides analyser. The necessary equipment is compact and sufficiently sturdy to allow shipboard use. A precision of 2nmol/l is claimed, and an analytical range of 2nmol/l with analysis rates of 10-12 samples hourly. 

Sakamoto [243] determined picomolar levels of cobalt in seawater by flow injection analysis with chemiluminescence detection. In this method flow injection analysis was used to automate the determination of cobalt in seawater by the cobalt-enhanced chemiluminescence oxidation of gallic acid in alkaline hydrogen peroxide. A preconcentration/separation step in the flow injection analysis manifold with an in-line column of immobilised 8-hydroxyquinoline was included to separate the cobalt from alkaline-earth ions. One sample analysis takes 8 min, including the 4-min sample load period. The detection limit is approximately 8 pM. The average standard deviation of replicate analyses at sea of 80 samples was 5%. The method was tested and inter calibrated on samples collected off the California coast. 

Lophine emits yellow CL upon oxidation by molecular oxygen in alkaline solution. The oxidation is believed to produce a free radical [3], which is further oxidized to a hydroperoxide, which is the light-emitting species [4-6], A number of chemiluminescent derivatives of lophine have been synthesized and have been shown to exhibit varying efficiencies of CL. Lophine has been used in the analysis of metal ions such as Co2+ that catalyze the chemiluminescent reaction between it and hydrogen peroxide [7], It has also been used as a chemiluminescent indicator in titrimetry [8],... 

In the past years, chemiluminescence (CL) analysis of inorganic compounds has been extensively developed in both gas and liquid phases. These methods typically rely on the oxidation or reduction of a chemically reactive agent and the subsequent emission of a photon from an electronically excited-state intermediate. 

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