Chemiluminescence intensity curve

Fig. 1. Time courses of the chemiluminescence intensity from oxalate—hydrogen peroxide systems in ethyl acetate as solvent, 0.7 mM TCPO. The curves correspond to the following concentrations of triethylamine (TEA) catalyst A, 0.05 mM B, 0.10 mM and C, 0.20 mM (70).

Provided that chemiluminescence intensity Iql is proportional to the rate of peroxyl radicals termination, that is Icl [PO ]2, which is often assumed in the literature, chemiluminescence intensity should achieve some quasi-stationary level when hydroperoxide concentration becomes stationary and its decay should correspond to consumption of oxidizable groups, PH, in a polymer. At the same time, the chemiluminometric curves of type (a), which are typical with an autoaccelerating increase of the light emission (Figure 4) are relevant for... 

In the published literature efforts exist to plot the so-called total chemiluminescence intensity (TLI) (surface below the chemiluminescence curve) vs. amount of oxygen absorbed [15]. In some cases a straight line may be obtained. A more detailed examination of the Equation (6) reveals that rate of oxygen uptake is in fact involved, so that we have... 

The case of reduction of chemiluminescence intensity for stabilized polymers of the chemiluminescence curves of the type (b) (Figure 5) has not yet been studied.)... 

Stopped-flow experiments of luminol chemiluminescence in the system luminol/pure DMSO/tert.butylate/oxygen 109> with independent variations of the concentrations of reactants confirmed the results obtained previously by E. H. White and coworkers 117> as to pseudo-first-order dependence of the chemiluminescence intensity upon each of the reactants. Moreover, the shapes of the decay curves obtained... 

The reaction of Ru(III) chelate with diimine is about 99 times more efficient than that of Ru(III) with hydrazine. Computer-simulated chemiluminescence time curves based on the kinetic data of the above reaction scheme exactly matched light-intensity time curves recorded in a stopped-flow spectrophotometer 166h At high hydrazine concentra-... 

If the reactants in a type I chemiluminescence reaction are rapidly mixed they will result in an emission whose intensity Ia, can be measured as a function of time. A typical time intensity curve for a CL reaction is shown in Figure 2. 

The chemiluminescence intensity is dependent on polymer, temperature and geometry. However, the relationship between the oxidation rate and the chemiluminescence intensity is not known and very few conclusions can be drawn from comparing light intensities between samples. In order to use chemiluminescence to determine the degree of oxidation, a correlation curve using a quantitative technique has to be constructed under the same ageing condition. 

Figure 22. Chemiluminescence intensity as a function of the average number of barium atoms (sfj, right) deposited per cluster. The curves show the variation of Poisson distributions of various orders as labeled.

Sample solution is diluted 40 times by 600 mmol/L sodium hydroxide, the diluted sample solution 50 /iL is poured into the plate. After addition of a luminescence solution (40 mmol/L potassium hexacyanoferrate (II ) and 0.1 mmol/L potassium hexacyanoferrate (III) containing 5 /nmol/L luminol solution), luminescence intensity was measured. Calibration curve was obtained by measurement of the chemiluminescence intensity using GPL as a standard, and the relative amount of the glycated protein in hair was computed. 

Chemiluminescence intensities were obtained as follows xanthine oxidase (0.37 units/mL, 40 pL) was added to the mixture consisting of 20 mM Mops/0.2 M KCl (pH 7.2, 0.5 mL), 0.3 mM hypoxanthine (0.5 mL), and 25 mM probe in water at 25 °C, then the reaction mixture was placed in an Aloka Luminescence Reader BLR-301 and chemiluminescent intensity time curves were obtained at 25 °C. Immediately after xanthine oxidase was added, the chemiluminescence with maximum intensity was observed. The intensity of background chemiluminescence was measured before the addition of xanthine oxidase. Chemiluminescence spectra were obtained as follows the luminescence solution was placed in a JASCO FP-750DS spectrofluorometer and spectra were obtained without light-irradiation. 

Figure 2. (A) Standard curve for the assay. The chemiluminescence intensity is expressed relative to the value obtained for 90 mg/dL of glucose. The bars indicate the standard deviations calculated from three determinations for each point. (B) Stability of the assay. Glucose concentration 90 ( ), 270 (o) mg/dL...

One of the chemiluminescence curves in ttie case when an oxygen-saturated solution of ethylbenzene was placed in the reaction vessel, is cited in Fig. 2. After introduction of the initiator, the chemiluminescence intensity rose rapidly, after which constant intensity of the luminescence was observed for a long time (curve 1). When the oxygen was almost entirely consumed, the concentration of radical RO began to decrease rapidly, which led to a decrease in the rate of recombination of these radicals and produced a decrease in the chemiluminescence intensity. At the lowest portion of curve 1, recombination of radicals R was observed, related to the smaller luminescence yield. 

Curve 2 shows the analogous drop of the chemiluminescence intensity as oxygen was consumed in the oxidation of methyloleate (at 60 C). 

Here, the emission occurs in the blue with maxima at 384 and 394 nm. The chemiluminescent intensity is proportional to the concentration of the excited sulfur dimer. Similarly, combustion of phosphorus compounds in a hydrogen flame gives emission due to HPO at, 526 nm. Linear working curves over four decades of concentration are reported. Both of these flame chemiluminescence techniques have been employed for detection of sulfur and phosphorus species in the effluent from gas chromatographic columns. 

Figure 8.5 shows typical kinetic curves in the coordinates of Eq. (9) for chemiliuninescence decay upon a short irradiation of PP. The behavior of the initial portions of the curves is determined by the conditions of photoinitiation, being dependent on the initial nonequilibrium distribution of the radicals over their reactivity and on the characteristics of the relevant relaxation processes [23]. The progress of the relaxation processes leads to the establishment of the exponential decay of the chemiluminescence intensity with a fixed rate constant k, which can be determined from the slope of the as5miptote of the kinetic curve in the ln l/lj-t coordinates. 

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... 

This approach allows to explain the quadratic time dependence of che-miliuninescence intensity changes (Eq. (IV)) describing the initial part of the kinetic curve (Fig. 23.6). Indeed, the chemiluminescence intensity is connected with emitter concentration by the relation ... 

Figure 2.8 shows the chemiluminescence curves of PP, HDPE and their blend after the first extrusion step. The PP exhibits a sharp peak at the maximum on chemiluminescence intensity, whereas the HDPE curve shows a broad bimodal behaviour [36]. In the chemiluminescence curves of the blend, all these features were observed. This may be a strong indication of the existence of a two-phase system in the molten state, which was also pointed out by Braun and co-workers [37], although this was based on peroxide treatment of PP/PE blend melts. It appears that PP oxidises first and the oxidation sites created during this process accelerate, to some extent, the oxidation of PE phase. The overlap between the PP and PE traces in the blend can be interpreted as the interface of these two phases where the PE starts oxidising. In addition, the shape of the curves confirms that the oxidation mechanisms of these resins are different, and that this difference remains during the oxidation of the hlend in the molten state. 

Using the plot of / vs. [InH], one finds k-j at known v,- and The inhibitor is consumed during the experiment, and therefore, the chemiluminescence intensity increases. The kinetic curve of chemiluminescence is s-shaped. The maximum angular coefficient of the chemiluminescence curve is... 

The dotted curves L in Fig. 3 represent the calculated time function related to the time required for the doubling of the chemiluminescence intensity ... 

Figure 7. Intensities of chemiluminescence in counts per minute after 1 week (t = 0) of storage of samples in Ar and with time (t) after exposure to air for samples irradiated in Ar plasma for 30 min in an open container (uppermost curve), a Cap2 container (middle curve), and a quartz container (lowest curve).

Luminous intensity-time curves and spectra of test samples stimulated thermally and photochemically were measured with a chemiluminescence spectrometer CLA-FSl. Colour photos of the photoluminescence of samples placed in a cell with a diameter of 50 mm were taken with the Cube-2DI, which is employing an ultra high sensitive colour CCD camera of Bitran Co., Japan. Both types of the apparatus are available from the Tohoku Electronic Industrial Co., Japan. The black light has power of 240 aW cm" and wavelength of 365 nm. In order to obtain a spectrum for steep decay photoluminescence curves, a sample was irradiated with the NUV light for 5 sec... 

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