Fluorescence spectrophotometry principles

Figure 18.8 Mercury analysis by cold vapour atomic fluorescence spectrophotometry (CVAFS). Measuring principle. (Model reproduced courtesy of P.S. Analytical). The fluorescence is measured at 90 ° with respect to the incident direction hy a photomultiplier tube.

The most commonly-used detectors are those based on spectrophotometry in the region 184-400nm, visible ultraviolet spectroscopy in the region 185-900nm, post-column derivativisation with fluorescence detection (see below), conductivity and those based on the relatively new technique of multiple wavelength ultraviolet detectors using a diode array system detector (described below). Other types of detectors available are those based on electrochemical principles, refractive index, differential viscosity and mass detection. 

In principle, any measurable property of a reacting system that is proportional to the extent of reaction may be used to monitor the progress of the reaction. The most common techniques are spectrophotometric (UV-visible, fluorescence, IR, polarimetry and NMR) or electrochemical (pH, ion-selective electrodes, conductivity and polarography). Either a "batch" method can be used, in which samples are withdrawn from the reaction mixture and analyzed, or the reaction may be monitored in situ. By far the most widely used technique involves UV-visible spectrophotometry. 

Atomic absorption spectrophotometry already then in its second edition. Price (1974) (Analytical Atomic Absorption Spectrometry) published about thelOth book on AAS since inception of the technique with the aim of being a textbook on practical AAS (FAAS). It contains the usual introduction to principles, instrumenttation and analytical techniques, with a large detailed chapter of applications to different materials followed by details for individual elements. A nice expanded version of the author s first book (Price 1979) on Spectrochemical Analysis by Atomic Absorption, includes newer developments such as EAAS. Kirkbright and Sargent (1974) (Atomic Absorption and Fluorescence Spectrometry) produced a massive, excellent, comprehensive treatise on the techniques of atomic absorption and fluorescence spectrometries, with details on... 

See also Chemiluminescence Overview. Chromatography Principles. Clinical Analysis Overview. Electron Spin Resonance Spectroscopy Biological Applications. Fluorescence Overview. Ion-Selective Electrodes Overview. Mass Spectrometry Overview. Microscopy Overview. Nuclear Magnetic Resonance Spectroscopy Overview. Ozone. Radiochemical Methods Overview. Sensors Overview. Spectrophotometry Overview. 

See also Electrophoresis Two-Dimensional Gels Nucleic Acids. Enzymes Enzyme-Based Assays. Flow Injection Analysis Principles. Fluorescence Quantitative Analysis. Lab-on-a-Chip Technologies. Mass Spectrometry Matrix-Assisted Laser Desorption/loniza-tion Time-of-Flight. Microelectrodes. Microscopy Overview. pH. Process Analysis Overview Chromatography Electroanalytical Techniques Sensors Acoustic Emission Maintenance, Reliability, and Training. Proteins Overview. Proteomics. Purines, Pyrimidines, and Nucleotides. Sensors Oven/iew. Spectrophotometry Overview. 

See also Activation Anaiysis Neutron Activation. Extraction Solvent Extraction Principles. Geochemistry Sediment. Ion Exchange Overview. Mass Spectrometry Ovenriew. Radiochemical Methods Gamma-Ray Spectrometry. Sample Dissolution for Elemental Analysis Dry Ashing. Spectrophotometry Overview. X-Ray Fluorescence and Emission X-Ray Fluorescence Theory. 

Principles and Characteristics Fluorescence spectroscopy can also be used for quantitation as it provides greater selectivity and sensitivity than UV spectrophotometry. Fluorescence quantitation can be described by eq. (6.6) ... 

Several direct spectrophotometric methods are used for sulfur dioxide measurement, including nondispersive infrared absorption, Fourier transform infrared analysis (FTIR), ultraviolet absorption, molecular resonance fluorescence, and second-derivative spectrophotometry. The principles of these methods are the same for any gas measured. 

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