We describe the separation of protoporphyrin and related porphyrins by reversed-phase "high-performance" liquid chromatography, with fluorometric detection. We used the method to demonstrate that acid hydrolysis of the dimethyl ester of protoporphyrin IX is complete in 2 to 3 h and is followed by the acid-catalyzed conversion of protoporphyrin IX to a chemical species that chromatographic evide...

A simple, rapid and highly sensitive fluorometric method for the determination of pazufloxacin mesilate (PZFX) is described. It is based on the formation of the complex [Tb(PZFX)2](3+), which shows the intensive characteristic bands of Tb3+. Optimum conditions for the determination were investigated. Under the optimum experimental condition, the fluorescence intensity responds linearly to the P...

Current cell-based assays for determining the functional properties of high-density lipoproteins (HDL) have limitations. We report here the development of a new, robust fluorometric cell-free biochemical assay that measures HDL lipid peroxidation (HDLox) based on the oxidation of the fluorochrome Amplex Red. HDLox correlated with previously validated cell-based (r = 0.47, p<0.001) and cell-free...

A simple batch method for the fluorometric determination of hydrogen peroxide using phosphine-based fluorescent reagents has been developed. A rapid, mild and selective derivatization reaction was achieved by adding sodium tungstate dihydrate to the reaction mixture of hydrogen peroxide and a phosphine-based fluorescent reagent. When 4-diphenylphosphino-7-methylthio-2,1,3-benzoxadiazole was use...

A highly sensitive and selective fluorometric method for the determination of histamine and histidine has been developed. This method is based on an intramolecular excimer-forming fluorescence derivatization with a pyrene reagent followed by reversed-phase liquid chromatography. The analytes, containing two amino moieties in a molecule, were converted to the corresponding dipyrene-labeled deriv...

A method is described for the simultaneous automated fluorometric estimation of noradrenaline and dopamine in brain extracts. It is based on a slight modification of the automated method for dopamine published recently. Interference of noradrenaline in the estimation of dopamine, and vice versa, is low (0.8 and 1.4%, respectively). Interferences of other catechols and related compounds have als...

The advantages of time-resolved fluorometry over conventional fluorometric analysis are well known. However, time-resolved fluorescence has not as yet found wide applications in protein microarray or other multiparametric methods of analysis. Here we describe a general method which is suitable for multiparametric and microarray analysis, based on time-resolved fluorometry. A polystyrene surface...

a sensitive fluorometric method for the determination of deferiprone (dfp) based on the formation of a luminescent complex with tb3+ ions in aqueous solutions is reported. the maximum excitation and emission wavelengths were 295 and 545 nm, respectively. the effects of various factors on the luminescence intensity of the system were investigated and optimized, then under the optimum conditions,...

Several different types of assay procedure have been proposed for the quantitative determination of thiamine. In a discussion (1) of the difficulties encountered in some of the methods, it has been pointed out that calorimetric (2, 3) and fluorometric (4) methods often suffer from a lack of sufficient sensitivity or specificity. The procedure described in the present communication, while not so...

Detailed cytochrome P450 (P450) inhibition profiles are now required for the registration of novel molecular entities. This method uses combined substrates (phenacetin, diclofenac, S-mephenytoin, bufuralol, and midazolam) with combined recombinant P450 enzymes (CYP1A2, 2C9, 2C19, 2D6, and 3A4) in an attempt to limit interactions with other more minor P450s and associated reductases. Kinetic ana...