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At least 721 records · Page 40Linked to original sources
PubMed1977

A rapid assay for urinary porphyrins by dual-wavelength spectrophotometry.

A procedure has been developed for the separation and quantitative assay of urinary porphyrins. Urine was directly diluted to a final concentration of 1 MHCl and the amount of porphyrins was determined from the peak-to-trough height deflection of the first derivatives of the absorption spectrum in the region of the Soret band. The ratio uro-/coproporphyrin was determined from the wavelength at which the spectrum intercepted the baseline. The specificity (as shown by a correlation coefficient of 0.99 compared to the method of Doss and Schmidt (1971) Z. Klin. Chem. Klin. Biochem. 9, 415-418), precision (coefficient of variation 5.2 percent) and sensitivity (lower detection limit approx. 0.01 mumol/l) of the present method were highly sufficient to estimate total and different porphyrins in the routine laboratory.

Coproporphyrins↗
PubMed2005

Determinations of fluoroquinolones and nonsteroidal anti-inflammatory drugs in urine by extractive spectrophotometry and photoinduced spectrofluorimetry using multivariate calibration.

Multivariate calibration methods are chemometric tools that may be applied to the analysis of spectroscopic data with multichannel detection. Two procedures, based on spectrophotometric and fluorimetric signals, are reported for the simultaneous determination of two fluoroquinolones (ciprofloxacin and ofloxacin) and two nonsteroidal anti-inflammatory drugs (diclofenac and mefenamic acid) using first- and second-order multivariate calibration methods. In the spectrophotometric method, an extractive procedure into chloroform using trioctylmethylammonium chloride-adogen as counter ion was optimized, with the object of extracting the analytes from urine samples and eliminating matrix interferences. After separation, the absorption spectrum of the organic phase was used as the analytical signal in a partial least squares method. A photoinduced spectrofluorimetric (PIF) method using excitation-emission fluorescence matrices, is proposed, to apply three-way chemometric calibration, with the aim of analyzing ofloxacin, ciprofloxacin, and diclofenac in urine samples without the previous extractive sample-cleaning step. For both procedures, recoveries around 100% were found for all the analytes. However, the PIF three-way chemometric method provides the most sensitive and selective procedure as the urine interferences are modulated using the three-way chemometric technique.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2005

Quantitative determination of ketoprofen in gels and ampules by using flow-injection UV spectrophotometry and HPLC.

A flow-injection UV spectrophotometric method for the determination of ketoprofen in gels and ampules was developed. Quantitative determination of ketoprofen was realized by using distilled water as a carrier for gels and citrate buffer, pH 6.5, for ampules at 261 nm. No spectrophotometric interferences from additives of gels, carboxypolymethylene and triethanolamine, were observed. There were also no spectrophotometric interferences resulting from additives of ampules named as benzyl alcohol and arginine. The detection limits were 0.436 and 0.303 microg/ml for gels and ampules, respectively. Throughout the study, the flow rate, loop volume and the number of injection per hour were 13.8 mlmin(-1), 193 mcirol and 85, respectively. Analytical signal of the ketoprofen was linear in the concentration range of 7.5-75 microg/ml. Quantitative results of ketoprofen in gels, 25.25+/-0.27 (mean+/-S.D.), and in ampules, 99.42+/-0.44 were in good agreement with the labeled quantities (25 mg/1g gel, 100 mg/2 ml ampule). The recoveries were in the range of 98.65-100.63 and 99.1-101.5% for gels and ampules, respectively. Results obtained were in accordance with those obtained by HPLC. It was seen that the proposed method was fast, accurate, precise and suitable for automation as an analytical method.

Acrylic Resins↗