Derivative synchronous fluorescence

Derivative synchronous fluorescence spectrometry is a useful technique for the simultaneous determination of related species in mixtures with no prior separation as it combines the assets of derivative [99] and synchronous... 

The use of second-derivative synchronous fluorescence spectrometry was reported by Ruiz et al. [42] to develop a simple, rapid and sensitive fluorimetric method for the determination of binary mixtures of the nonsteroidal antiinflammatory drugs flufenamic (FFA), meclofenamic (MCFA) and mefenamic (MFA) acids in serum and in pharmaceutical formulations. The method is based on the intrinsic fluorescence of these compounds in chloroform. A differential wavelength of 105 nm was used for the resolution of FFA-MFA and MFA-MCFA mixtures, whereas the FFA-MCFA mixture was determined at a differential wavelength of 40 nm. Serum samples were treated with trichloroacetic acid to remove the proteins, and the analytes were extracted in chloroform prior to determination. Pharmaceutical preparations were analyzed without prior separation steps. 

Kang et al. [50] developed the first derivative synchronous fluorescence method for simultaneous assay of traces of some polycyclic aromatic hydrocarbons in human urine. Proposed method was fast, sensitive, selective and reliable. The results were comparable with those obtained by HPLC method. 

Histamine in foods is primarily the result of microbial decarboxylation of histidine, and so it is a customary constituent of fermented foodstuffs such as wine and cheese, and foods with a fairly high histidine concentration (e.g., tuna fish) that have been exposed to microbial degradation. It is routinely determined in foods using fluorimetric methods involving condensation with OPA. Second-derivative synchronous fluorescence spectrometry has also been used for the direct quantification of histamine in wine and canned tuna. 

Wakeham [14] has discussed the application of synchronous fluorescence spectroscopy to the characterization of indigenous and petroleum derived hydrocarbons in lacustrine sediments. The author reports a comparison, using standard oils, of conventional fluorescence emission spectra and spectra produced by synchronously scanning both excitation and emission monochromators. 

The second observed trend is an association of derivatisation with others instrumental methods. Every set of digital data can be subjected derivatisation. So this mathematical approach was applied for data processing with synchronous fluorescence spiectroscopy. The second derivative synchronous fluorimetry was used for simultaneous determination of sulpiride and its degradation product [49]. For quantification were used amplitudes of peaks at 295.5 nm and at 342 nm corresponded to main compound and its degradate, respectively. The method was applied for studies of the kinetics of alkaline degradation of drug. 

SPLS is very sensitive and selective for organic trace analysis. Detection limits of a nanogram or even a picogram can be obtained. The methodology is simple, inexpensive, relatively precise (2-20%), relatively rapid, can handle small samples, and can be very selective in mixture analysis when solid-phase fluorescence (SPF) and solid-phase phosphorescence (SPP) are combined or when using derivative, synchronous, or time-resolved SPLS. Additionally, SPLS is well suited to being combined directly with both thin-layer and paper planar chromatography. 

Recent research has intensified the search for portable instruments for real-time monitoring of airborne PAHs, particularly in the industrial enviromnent. A derivative UV absorption spectrophotometer has been used for real-time monitoring of a small number of aromatic vapors. When synchronous fluorescence and room-temperature phosphorescence (using a... 

Kalbitz, K., and Geyer, W. (2001). Humiflcation indices of water-soluble fulvic acids derived from synchronous fluorescence spectra - effects of spectrometer type and concentration, J. Plant Nutr. Soil Sci., 164(3), 259-265. 

Fig. 7. Excitation, fluorescence, and synchronously-scanned spectra of oestrone in ethanol, and their second derivatives. A, excitation spectrum monitored at a fluorescence wavelength, Af B, fluorescence spectrum obtained at an excitation wavelength, Aex C, synchronously-scanned spectrum obtained with a constant interval, AA, between the excitation and emission monochromators. (From A. F. Fell, in Proc. 1st Symp. Anal. Steroids, Eger, Hungary, S. Gorog (Ed.), Amsterdam, Elsevier Press, 1982, pp. 495-510.)...

Fluorescence polarization has proved to give high sensitivity in determination of avidin and biotin by means of the fluorescein conjugate. Synchronous derivative spectroscopy can also be useful as exemplified by measurement of pesticide compositions . 

Lin CH, Fukii H, Imasaka T, et al. 1991. Synchronous scan luminescence techniques monitoring resonance and non-resonance fluorescence in supersonic jet spectrometry applied to anthracene derivatives. Anal Chem 63(14) 1433-1440. 

Fluorescence applied to oil identification has been an active field, with 17 papers presented on the subject at the last three Pittsburgh Conferences. A number of interesting developments for fluorescence and low-temperature luminescence (LTL) are described by Eastwood et al. (58). These include synchronous scanning, difference spectrofluorometry, synchronous difference spectroscopy, derivative spectroscopy, and total luminescence (or contour) spectroscopy and combinations of these techniques. In a recent presentation, Eastwood and Hendrick (59) reported an extension of their low-temperature luminescence studies to include polarized excitation and emission spectroscopy, and time-resolved phosphorescence. Preliminary studies of polarization effects indicate that differences exist in low-temperature polarized luminescence spectra of oils, which may aid in oil identification. In the time-resolved phosphorescence spectra of oils, the most significant difference observed was enhancement of the vanadyl porphyrin signal at approximately 700 nm for short delay times (20 fxsec). 

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