High spectrofluorimetry

Chemical Testing. Adequate instrumentation for a variety of different test methods should be available. Most stability-indicating chemical assays are performed by high-performance liquid chromatography. Occasionally, gas chromatography, infrared spectrophotometry, or spectrofluorimetry are used. Test... 

Saber et al. [75] reported on the quantitative determination of polyaromatic hydrocarbons in extracts of lacustrine sediments using high resolution Shpol skii Spectrofluorimetry at 10°K. 

Garrigues and Emald [76] give details of a procedure for the determination of polycyclic aromatic hydrocarbons in sediment samples by high resolution Spectrofluorimetry in n-alkane matrices. 

Saber et al. [75] used high resolution Shpol skii spectrofluorimetry at 10°K to quantitatively determine polyaromatic hydrocarbons in lacustral sediments. Polyaromatic hydrocarbons incorporated into w-alkanc matrix... 

Various analytical techniques have been employed to determine the drug content in nanoparticles after the separation procedures. High performance liquid chromatography and UV/vis spectroscopy are two of the most extensively used techniques [133], Other techniques used include scintillation counting [186], spectrofluorodensitometry [176], microbiological assays [136], spectrofluorimetry [187], and polarization fluoroimmunanalysis [67],... 

Those experimentalists who use spectrophotometry or spectrofluorimetry to measure rates of biochemical reactions should always be mindful that bubble clearance frequently displays first-order kinetics. This applies to bubbles adhering to the inside wall of the cuvette as well as bubbles released from solution itself. The presence of bubbles within a cuvette may introduce artifactual kinetic behavior resulting (a) from refractive index differences between the gas trapped in the bubbles and that of the test solution, and (b) from the high reflectance of the air/water interface surrounding some bubbles. 

MA Rouet-Mayer, O Valentova, E Simond-Cote, J Daussant, C Thevenot. Critical analysis of phospholipid hydrolyzing activities in ripening tomato fruits. Study by spectrofluorimetry and high performance liquid chromatography. Lipids 30 739-746, 1995. 

The variety of sampling methods available in spectrofluorimetry makes it a very versatile technique. The most frequent mode of sample presentation is as a dilute solution, although gases, suspensions, and solid surfaces can also be examined. Combinations of spectrofluorimetry with thin-layer chromatography and high pressure liquid chromatography are particularly advantageous for sensitive and selective detection offluorophores. 

Because of the biological and pharmaceutical interest in phenothiazine derivatives, these compounds have been used in a variety of analytical studies and applications. For a number of years, several analytical methods have been proposed by various groups for the determination of phenothiazine and its derivatives in pharmaceutical formulations and biological fluids, including thin-layer chromatography (TLC) [51-54], high-performance liquid chromatography (HPLC) [55-58], spectrofluorimetry, either direct or with derivatization [59-64], flow-injection analysis (FIA) [10,65-73] and other techniques [11,74-76]. 

Zerbinati, O., Ostacoli, G., Gastaldi, D., and Zelano, V., Determination and identification by high-performance liquid chromatography and spectrofluorimetry of twenty-three aromatic sulfonates in natural waters, J. Chromatogr., 640, 231-240, 1993. 

Shpol skii spectrofluorimetry has been used for the determination of PAHs in crude enviromnental sample extracts with minimum sample cleanup. This technique gives a vibrationally resolved fluorescence spectrum of samples dissolved in a suitable solvent (usually an -alkane) at cryogenic temperatures, e.g., 26 K. It combines the selectivity of an infrared spectrum with the sensitivity of fluorimetry, though the sensitivity suffers considerably from the presence of large amounts of interfering substances such as fatty components in crude extracts since these give a poor-quality matrix with a high sample absorbance. 

We have seen the relationship between absorption spectrophotometry and spectrofluorometry. A similar relationship exists between atomic absorption spectrophotometry and atomic fluorescence spectrophotometry. In atomic fluorescence, the flame retains its role as a source of atoms these atoms, however, are excited by an intense source of radiation and their fluorescent emission is assayed at an angle of 90° in a manner similar to that of spectrofluorimetry. Lack of sufficiently intense source for many elements has been the limitation of this technique, however, with time instrumental developments are overcoming this problem. High intensity hollow-cathode lamps, or xenon or mercury discharge lamps are used. 

To study the interaction of retinol-binding protein (RBP) with its plasma carrier, transthyretin (TTR), spectrofluorimetry, and circular dichroism have previously been used. Both these techniques require milligram quantities of the proteins and this sets limitations on the use of these techniques for the study of RBP-TTR interactions using recombinant proteins. The Escherichia coll expression system described in Chapter 11 does not readily produce milligram quantities of RBP for routine use. For this reason, we have developed a highly sensitive method which employs radioiodinated I-RBP (unpublished). The method requires only microgram quantities of protein. This chapter describes a method to radioiodinate RBP without loss of activity and protocols for its use in the study of its interaction with TTR. 

In a study by spectrofluorimetry, Duggan, Bowman, Brodie and Uden-friend found that in phosphate buffer pH 7, cyanocobalamin had an activation maximum at 275 m t and a fluorescence maximum at 305 m/bc and that a practical sensitivity of 0-003 jug of cyanocobalamin per ml was obtainable. Since fluorometric methods usually have high sensitivity and specificity, these considerations may enable a valuable method to be developed for the determination of cyanocobalamin, in particular since it may overcome interference by analogues and other cobalamins. 

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