Chemiluminescence signal

The authors also demonstrated a low-technology method for recording the chemiluminescent signal of the bDNA assay. The light emission was recorded on black-and-white film Polaroid film using a handheld camera. The bDNA assay could be applicable to field situations because of the stability of the reagents and the ability to record the data without the use of sophisticated equipment. 

The intensity of chemiluminescence signal from a heated polymer and the kinetics of its change with time or temperature is determined by [30] ... 

Figure 9 demonstrates the fact that the chemiluminescence process occurs predominantly in the amorphous phase of the polymer. Low molar mass dicaproyl hexamethylene diamide is a fully crystalline compound the chemiluminescence signal under isothermal conditions below the melting point (136°C) at 130°C is very low, but it becomes rather strong after the crystallites of... 

Figure 22 Continual changes of the intensity of chemiluminescence signal with concentration of oxygen in the surrounding atmosphere, 180°C, for Whatman cellulose paper. Numbers are % vol. of oxygen in the mixture with nitrogen.

The chemiluminescence technique has been used to determine trivalent chromium in seawater. Chang et al. [187] showed Luminol techniques for determination of chromium (III) were hampered by a salt interference, mainly due to magnesium ions. Elimination of this interference is achieved by seawater dilution and utilising bromide ion chemiluminescence signal enhancement (Fig. 5.7). The chemiluminescence results were comparable with those obtained by a graphite furnace flameless atomic absorption analysis for the total chromium present in samples. The detection limit is 3.3 x 10 9 mol/1 (0.2 ppb) for seawater with a salinity of 35%, with 0.5 M bromide enhancement. 

Finally, Yamada and Suzuki made a comparative study of the use of DDAB, HTAB, STAC, and CEDAB to improve the sensitivity and selectivity of the determination of ultratraces of Cu(II) by means of the CL reaction of 1,10-phenanthroline with hydrogen peroxide and sodium hydroxide, used as detection in a flow injection system [46]. Of the four cited surfactants it was found that CEDAB causes the greatest enhancement of the chemiluminescent signal (Fig. 12) (an enhancement factor of 140 with respect to the absence of surfactant). 

The most widely used gas-phase chemiluminescence reagent is ozone. Analytically useful chemiluminescence signals are obtained in the reactions of ozone with NO, SO, and olefins such as ethylene and isoprene, but many other compounds also chemiluminesce with ozone. Ozone is conveniently generated online at mixing ratios of =1-5% by electrical discharge of air or 02 at atmospheric pressure [14]. 

While investigating the potential for an instrument to measure atmospheric dimethyl sulfide (DMS) [69], discussed below, Hills et al. investigated the possibility of adding H2 to the reaction cell to provide chemical amplification of the chemiluminescence signal via the catalytic chain reaction ... 

Figure 4 Quartz microbalance electrode with a protein A-HRP conjugate immobilized on the gold surface, (a) Transmitted light image (b) chemiluminescent signal after addition of CL substrate (c) 3-D display of the light signal spatial distribution.

Figure 8 HRP calibration curve (log-log plot of HRP dose vs. chemiluminescence signal, corrected for background) using signal reagent incorporating GZ-11.

Large amounts of IAA-peptide in the seeds present in the tissue section caused bleeding of the chemiluminescence signal leading to a loss of anatomical detail. This may be alleviated by decreasing the exposure time of the film to a blot. To decrease the amount of antigen transferred to the blot, rinse the freshly cut tissue section in distilled water for 3-5 s. Alternatively, blot serial sections on the nitrocellulose. 

Several chemiluminescence methods have also been developed for S02. For example, S02 has been shown to enhance the chemiluminescence signal from the luminol-N02 reaction so that the enhancement can be used as a measure of S02 at a fixed NOz concentration (Zhang et al., 1985). Another method involves the formation of SO in a hydrogen flame followed by reaction with 03 to generate electronically excited S02 whose emission is followed at 340 nm (e.g., see Benner and Stedman, 1990). 

Chemiluminescent labeling systems have been developed, based on the incorporation of fluorescein-11-dUTP into a DNA probe. An anti-fluorescein antibody covalently bound to the enzyme HRP is then bound to the incorporated fluorescein label. HRP catalyses the breakdown of luminol and the chemiluminescent signal is detected by autoradiography with X-ray film or by fluorescence scanning instrumentation. Chemiluminescence is more sensitive than enzyme-based color detection systems. Furthermore the labeled gene probes are stable and give results quickly (160). 

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