Fluorescence and Chemiluminescence Spectroscopy

2 Fluorescence and Chemiluminescence Spectroscopy. - The fluorescence excitation spectrum of PF3 at 9-13 eV, using monochromatised synchrotron radiation, has been examined to resolve the pyramidal geometry of the X Ai ground state of the PFs cation, which was also confirmed by ab initio calculations. Dimethylamino-substituted triphenylphosphines exhibit dual fluorescence in polar solvents, and fluorescence-decay measurements have shown that the photo-induced intramolecular charge-transfer process occurs in a few picoseconds, even in weakly-polar solvents. 

A transient absorption band, with a profile similar to that of the dimethylani-line radical cation, was observed in polar solvents by time-resolved picosecond absorption spectroscopy. 

Chemiluminescence has been used to assess phosphatidylcholine oxidation, and to measure the kinetics of decomposition of hydroperoxides formed during the oxidation of soya phosphatidylcholine. The direct chemiluminescence method correlated well with other methods of determining oxidation status (chemical, UV, HPLC, and microcalorimetry), and it was concluded that chemiluminescence was an ideal method for estimating the oxidation of phosphatidylcholine (and phospholipids in general). Kinetics measurements revealed that 

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H. Herman, Uv-Vis, fluorescence and chemiluminescence spectroscopies in chemical process analysis, in Spectroscopy in Process Analysis, J.M. Chalmers (Ed), CRC Press, Boca Raton, 1999. 

Depending on the type of reaction and analytes to be investigated, different optical spectroscopic methods are available [7]. Typically UV-Vis, near-infrared (NIR), mid-infrared (MIR) and Raman spectroscopy are the most popular in process analysis (see Table 6.1) [8]. Other, emerging in-line methods such as fluorescence and chemiluminescence spectroscopy are still of minor importance in process technologies and will be not discussed here (for additional information, see [9]). 

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