Light emission detectors

Recently, Orosz et al. [136] reviewed and critically reevaluated some of the known mechanistic studies. Detailed mathematical expressions for rate constants were presented, and these are used to derive relationships, which can then be used as guidelines in the optimization procedure of the POCL response. A model based on the time-window concept, which assumes that only a fraction of the exponential light emission curve is captured and integrated by the detector, was presented. Existing data were used to simulate the detector response for different reagent concentrations and flow rates. 

In TL, the light emission induced in the mineral or ceramics sample heated up to 500° C is measured by means of a photomultiplier detector. In addition to laboratory instrumentation, portable gamma spectrometers have been used when circumstances make sampling impractical. 

Although tocopherols and tocotrienols can be detected by UV absorbance at 280 nm, fluorescence detection (excitation 294 nm and emission 326 nm), as shown in Figure 11.3, has proven to be a much more sensitive method. Electrochemical detection such as pulsed amperometric and coulometric (Uspitasari-Nienaber, 2002) has also proven to be sensitive and potentially valuable for the quantitative analysis of tocopherols and Tocotrienols (Abidi, 2000), especially for tocol analysis in blood and serum samples. HPLC mass detectors such as flame-ionization detectors, evaporative light-scattering detectors, and charged aerosol detectors have proven to be valuable for the quantitative analysis of many types of lipids, but because tocols have... 

The components of the fluorimeter include (Fig. 7.5) (1) power supply—powers the lamp (2) light source—UV -vis lamp (3) excitation monochromator—selects a particular wavelength of light from the lamp to excite the sample (4) sample—solution in a cuvette in a holder (5) emission monochromator—scans through a set of wavelengths where the sample emits light (6) detector—a photomultiplier tube PMT detects the number of... 

Before considering detector characteristics and some recent developments in chemiluminescence detection, it should be noted that analytical applications of chemiluminescence involve two types of chemiluminescent response. In the first type, the chemiluminescent molecule is used as a detection label and is, therefore, present in limiting concentration relative to the reagents used to initiate the chemiluminescent reaction. The chemical reaction will therefore be pseudo first order. The slowest process in the sequence of events leading to light emission is the reaction itself, e.g., hydrolysis, bond-breaking, and rearrangements. From Eq. 

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