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Fluorimetric Method (fluorimetric + method)

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Chemistry100%

Selected Abstracts

Flow-Through Assay of Quinine Using Solid Contact Potentiometric Sensors Based on Molecularly Imprinted Polymers

ELECTROANALYSIS, Issue 24 2009
Ayman
Abstract Miniaturized potentiometric membrane sensors for quinine incorporated with molecular imprinted polymer (MIP) were synthesized and implemented. Planar PVC based polymeric membrane sensors containing quinine-methacrylic and/or acrylic acid-ethylene glycol methacrylate were dispensed into anisotropically etched wells on polyimide wafers. The determination of quinine was carried out in acidic solution at pH,6, where positively charged species predominated prevalently. The suggested miniaturized planner sensors exhibited marked selectivity, sensitivity, long-term stability and reproducibility. At their optimum conditions, the sensors displayed wide concentration ranges of 4.0×10,6,1.0×10,2mol L,1 and 1.0×10,5,1.0×10,2 mol L,1 with slopes of about 61.3,55.7,mV decade,1; respectively. Sensors exhibit detection limits of 1.2×10,6 and 8.2×10,6 mol L,1 upon the use of methacrylic and acrylic acid monomers in the imprinted polymer, respectively. Validation of the assay method according to the quality assurance standards (range, within-day repeatability, between-day variability, standard deviation, accuracy, and good performance characteristics) which could assure good reliable novel sensors for quinine estimation was justified. Application of the proposed flow-through assay method for routine determination of quinine in soft drinks was assayed and the results compared favorably with data obtained by the standard fluorimetric method. [source]

A fluorimetric method for the determination of trace pentachlorophenol, based on its inhibitory effect on the redox reaction between the improved Fenton reagent and rhodamine B

LUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 5 2007
Huiqin Guo
Abstract A sensitive fluorimetric method is presented and discussed for the determination of pentachlorophenol in aqueous solutions. This method is based on the inhibitory effect of pentachlorophenol on the reaction of conventional Fenton [Fe(III) + H2O2] reagent with rhodamine B in the medium of perchloric acid, which results in the fluorescence quenching of rhodamine B. It was further found that the sensitivity for the determination was improved significantly when the molecular ligand EDTA was added. This improved system was therefore presented for the determination of pentachlorophenol. The characteristics of the excitation and emission spectra, optimization of the experimental conditions, the stability of the system and the influence of foreign matter have all been investigated. Under optimal conditions, the linear range for the determination of pentachlorophenol is 12,480 ng/mL with a 3, limit of detection of 0.96 ng/mL. Compared with the conventional Fenton system, the improved system shows obvious advantages in both sensitivity and selectivity. By combination with the pretreatment of samples using ion exchange resins and XDA-1 absorption resin, the improved Fenton method was used for the first time for the determination of pentachlorophenol in synthetic samples and natural water samples, and satisfactory results, in agreement with those of the HPLC method, were achieved. The possible mechanism of the reactions has also been discussed. Copyright © 2007 John Wiley & Sons, Ltd. [source]

A New Fluorimetric Reagent for Determination of Trace Amounts of Europium

CHINESE JOURNAL OF CHEMISTRY, Issue 9 2002
Peng Lin
Abstract In this paper, a new ligand, 2, 9-bis [N, N -bis (carboxymethyl) -aminomethyl] ,1, 10-phenanthroline, was synthesized and used to establish a novel fluorimetric method for the determination of trace amounts of europium. The fluorescence intensity was a linear function of the concentration of europium in the range,of 4.0 × 10,9,1.0 × 10,6 mol/L. The detection limit was 1.0 × 10,9 mol/L. The standard addition method was used to determine the europium in a synthetic rare-earth sample and high purity Y2O3 matrix with satisfactory results. [source]