Phase fluorimetry

Triprolidine hydrochloride in syrups and tablets can be analyzed by fluorimetry. A portion of the tablets or syrup is made basic with IN NaOH and extracted with ethylene chloride. The organic phase is then extracted with 0.1N I SO. The fluorescence of the acid extract is determined with a fluorometer using a UG11 filter for excitation and a Wratten 2A filter for emission. The fluorescence of the sample preparation is compared against a Reference Standard prepared in the same manner22. 

J. R. Lakowicz, H. Szmacinski, and M. Karakelle, Optical sensing of pH and pC02 using phase-modulation fluorimetry and resonance energy transfer. Anal. Chim. Acta 272, 179-186 (1993). 

J. R. Lakowicz and B. Maliwal, Optical sensing of glucose using phase-modulation fluorimetry,... 

The use of off-gas analysis, however, is a relatively expensive proposition as a means ofmonitoring/controlling extracellular parameters. It is also an indirect method and is generally used to obtain information about the synthesis of products that cannot be analyzed directly. It is possible, however, to use inexpensive phase fluorimetry-based pCD and pCCh sensors to obtain the same information. 

T. Parassassi, F. Conti, M. Glaser, and E. Gratton, Detection of phospholipid phase separation. A multifrequency phase fluorimetry study of l,6-diphenyl-l,3,5-hexatriene fluorescence, J. Biol. Chem. 259, 14011-14017 (1984). 

Ion exchanger colorimetry has been used as a sensitive and rapid method for vanadium analysis by immobilization of 2[2-(3-5-dibromopyri-dyl)azo]-5-dimethylaminobenzoic acid onto an ion exchanger resin AG 1X2 [75]. Solid phase fluorimetry can be useful for the analysis of very dilute solutions in water analysis or trace metal determination thus a chelating 8-(benzene-sulfonamido)quinoline, immobilized on Amberlite XAD2 support, has been used for the spectrofluorimetric determination of Zn(II) and Cd(II) [76]. 

B) Phase-shift methods. The phase shift method for determining fluorescence lifetimes is based on the principle that if fluorescence is excited by suitably modulated light source, emitted radiation will also be similarly modulated. With reference to a scattering substance, emission from a fluorescent substance will introduce a time lag due to finite time between absorption and emission. This, by definition is the lifetime of the excited state. The time lag will cause a phase-shift relative to the exciting light. Phase fluorimetry requires a modulated light source and a phase sensitive detector. 

The substrate and two products are separated on a //.Bondapak TM C]8 column (3.9 mm x 300 mm). The mobile phase consisted of 0.05 M acetate buffer (pH 4.7), 10 mM Na2S205, 1 mM EDTA, and 25% methanol. The column effluent was monitored by fluorimetry with exdtation, and emission wavelengths being 295 and above 340 nm, respectively. 

Phase fluorimetry is another useful fluorimetric technique for the determination of substances with overlapping fluorescence spectra. In phase fluorometry, the... 

Ce Reversed-phase bis-(2-ethylhexyl)phos-phate Sea water Fluorimetry + 1 ng/1 167)... 

In Reversed-phase tri-butylphosphate Gallium Fluorimetry + Rhodamin G 18 ppm 135)... 

Se Reversed-phase as -piazselenol or diethyl-dithiocarbamate UV, fluorimetry ng- To pg-Levels ... 

Further applications are described for sulfur (Fig. 2.6) and copper in water by reversed-phase or ion-exchange high-performance liquid chromatography . Also anions such as thiosulphate and polythionates were separated from environmental samples by HPLC (anion-exchange) . The sensitive detection was made possible by reaction with Ce(lV) after separation and fluorimetry of Ce(lII) ions. 

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