Luminescence fluorescence

TGA, iodometric, mid-IR, luminescence (fluorescence and phosphorescence) and colour formation (yellowness index according to standard method ASTM 1925) were all employed in a study of aspects of the thermal degradation of EVA copolymers [67], Figure 23 compares a set of spectra from the luminescence analysis reported in this work. In the initial spectra (Figure 23(a)) of the EVA copolymer, two excitation maxima at 237 and 283 nm are observed, which both give rise to one emission spectrum with a maximum at 366 nm weak shoulders... 

Oligonucleotide probes may be labeled with small fluorescent molecules for detection of hybridization by luminescence. Fluorescent probes are widely used in assay systems involving bio-specific interactions (Chapter 9). Receptors for ligands may be localized in tissues or cells by modification of the ligand with the appropriate fluorophore. Targeted molecules may be... 

Luminescence instrument LS-3B luminescence instrument LS-5B Accessories low flow cell, cell holders, bioluminescence spectroscopy, fluorescence spectro scopy, recorder/printers, low-temperature luminescence, fluorescence plate reader, polarization accessory, microfilm fluorimeter LS-2B... 

The radiation may be due to emissions from a hot source, or to the luminescence, fluorescence or phosphorescence of the sample. An emission spectrum consists of a number of generally very narrow peaks (called spectral lines) occurring at certain wavelengths which are characteristic of the materials contained within the source. The amplitudes of the peaks are related to the abundance or concentration of the materials present. Alternatively, radiation from a source is passed through a sample. In this case the quantity absorbed by the sample at a particular wavelength is again characteristic of the materials present in the sample. This is termed absorption spectrometry and produces spectral transmission lines in the form of equally narrow valleys—or peaks (Fig. 6.42) where the information is expressed in terms of absorbance (si) rather than transmittance (20<57>, and ... 

The transducers most commonly employed in biosensors are (a) Electrochemical amperometric, potentiometric and impedimetric (b) Optical vibrational (IR, Raman), luminescence (fluorescence, chemiluminescence) (c) Integrated optics (surface plasmon resonance (SPR), interferometery) and (d) Mechanical surface acoustic wave (SAW) and quartz crystal microbalance (QCM) [4,12]. 

Luminescence spectrophotometry consists of fluorescence, phosphorescence and low-temperature total luminescence. Fluorescence is generally measured at room temperature. Phosphorescence is generally observed at liquid nitrogen temperature (77K) with the aid of a chopper to interrupt the exciting radiation. Total luminescence is the combined fluorescence and phosphorescence obtained at low temperature (77K). Luminescence spectrophotometry is generally much more sensitive and specific than absorption spectrophotometry. 

Trends in biochemical screening assays seem to favor the use of multi-function PMT-based readers that allow for various MTP well densities (96, 384, and 1536 well plates), can handle a number of readout formats such as prompt fluorescence, luminescence, fluorescence polarization, time-gated fluorescence, and luminescent oxygen channeling or AlphaScreen. Examples of this type including the Perkin Elmer EnVision, TECAN-Ultra, BMG FluoStar, and LJL Analyst GT can be employed for a variety of the assay technologies described above. 

Several rather basic azamacrocycles act as receptor components within lumo/fluorophore-spacer-receptor systems (29) [82], (30) [83] and (31) [84], which are at least structurally related to PET sensors. However, the lack of any substantial luminescence/fluorescence quenching in the cation-free state suggests that the thermodynamic criteria for PET (Eq. (1)) are not met in some of these cases. The low luminescence quantum yields seen in some variants of (31) [84] are due to the intrusion of metal centered lowest excited states. Related cases, with or without macrocyclic units, (32) [85] and (33) [86] carry the... 

Several optical methods have been used for DNA sensing, such as luminescence, fluorescence Raman or optical waveguide structure spectroscopy, and surface plasmon resonance (SPR). Various immobilization strategies to attach ssDNA to surfaces with the aim of attaining maximum selectivity and sensitivity have been described. 

Emission of a photon from an electronically excited state is referred to as luminescence. Fluorescence and phosphorescence can be differentiated depending on whether the transition is between states of equal or different multiplicity and hence spin-allowed or spin-forbidden. (Cf. Section 5.1.1.) Thus, for molecules with singlet ground states fluorescence constitutes a pathway for deactivating excited singlet states whereas phosphorescence is observed in the deactivation of triplet states. 

Figure 4-10 General design for in vitro optical sensor designed to detect given analyte in blood sample. Polymer film contains dye that changes spectral properties in proportion to the amount of analyte in the sample phase. Example shown is for sensing film that changes luminescence (fluorescence or phosp horescence).

Multimode CCD image detection (UV/Vis, TRF, TR-FRET luminescence, fluorescence) simultaneously from all wells of a microplate... 

Format/signal generation technologies Heterogenous— wash, e.g., ELISA, SEAP reporters colorimetric, absorbance homogeneous— luminescence, fluorescence, FRET Homogeneous—Imninescence, fluorescence, TR-FRET, FPA, AlphaScreen ... 

Fig. 4. Relative position of lower excited singlet state (S,), triplet state (Tt) and metal ions (Mi), electronic levels, and transitions between them in metal ion complexes with organic ligands, (A) luminescence (fluorescence and phosphorescence) with levels of metal ion located above Sr levels, (B) phosphorescence with metal ion levels located between S,- and Trlevels, (C) sensitized (native) luminescence with metal ion levels located below Ti-levels...

Prepared from magnesium or magnesium oxide and o-cyanobenzamide (40), magnesium phthalocyanine has been the subject of much study since it is a synthetic analog of chlorophyll. Perhaps understandably, much of this work has been connected with photosynthesis, luminescence, fluorescence, etc. (see Section V,B). The molecular weight of magnesium phthalocyanine has been measured ebullioscopically in naphthalene (228). Because of the very low solubility of the substance, a very accurate platinum thermometer was employed. Nevertheless the successful measurement represents quite an achievement. 

Key words TNT, explosives, sUole, germole, polysilane, pofygermole, polysilole, sensors, luminescence, fluorescence, nitroaromatics, quenching, inorganic polymers... 

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