Search results for "pero"
showing 10 items of 3365 documents
Influence of water sample storage protocols in chemiluminescence detection of trace elements.
2002
This paper shows the influence of different sample storage protocols, on the chemiluminescence signal of some metal ions. The storage protocols studied were: acid addition (HCl or HNO(3)) and no reagent addition to filtered and refrigerated (T=4 degrees C) samples. Light emission was produced for the chemiluminescence reaction between luminol and hydrogen peroxide in buffer carbonate conditions (pH 10.8) catalysed by Cr(III), Co(II) and Cu(II). Batch and/or flow modes in different conditions were tested. Fe(II), Fe(III), Ni(II) and Mn(II) did not give chemiluminescence in the studied conditions. A parallel study of sensitivity and selectivity was performed. Then the presence or absence of t…
Determination of mercury in rice by cold vapor atomic fluorescence spectrometry after microwave-assisted digestion.
2010
Abstract A cold vapor atomic fluorescence spectrometry method (CV-AFS) has been developed for the determination of Hg in rice samples at a few ng g−1 concentration level. The method is based on the previous digestion of samples in a microwave oven with HNO3 and H2O2 followed by dilution with water containing KBr/KBrO3 and hydroxylamine and reduction with SnCl2 in HCl using external calibration. The matrix interferences and the effect of nitrogen oxide vapors have been evaluated and the method validated using a certified reference material. The limit of detection of the method was 0.9 ng g−1 with a recovery percentage of 95 ± 4% at an added concentration of 5 ng g−1. The concentration level …
GFAAS determination of selenium in infant formulas using a microwave digestion method.
1994
A method for determining the selenium content of infant formulas is proposed. It includes wet digestion with nitric acid and hydrogen peroxide in medium pressure teflon bombs in a microwave oven and determination by graphite furnace atomic absorption spectrometry (GFAAS). The absence of interferences is checked. Values obtained for the limit of detection (19.4 ng/g), precision (RSD = 2.2%) and accuracy by analysis of a reference material show that the method is reliable.
FI automatic method for the determination of copper(II) based on coproporphyrin I-Cu(II)/TCPO/H(2)O(2) chemiluminescence reaction for the screening o…
2004
Abstract In this paper, an automatic method for the screening of water samples containing Cu(II) was proposed, based on peryoxalate chemiluminescence reaction using coproporphyrin I as fluorophor compound to provide selectivity and a simple flow injection (FI) chemiluminescence detector (CLD). FI system conditions were chosen in order to distinguish samples over or under legislation limit established (50 μg l−1) with high reliability. The detection limit found was 9 μg l−1 and the linear dynamic range was 15–125 μg l−1 of Cu(II). Repeatibility and reproducibility studies gave good precision and accuracy with recovery near 100%. Under these conditions, the method resulted selective and only …
Photo-induced chemiluminescence determination of the pesticide Buminafos by a Multicommutation flow-analysis assembly
2008
Abstract The preliminary experiments in this paper deal with the photo-induced chemiluminescent behaviour of Buminafos family, after the experimental screening tests and several of them resulted positive, the herbicide Buminafos was selected to develop a new analytical method. The determination of Buminafos was performed with the aid of a Multicommutation (a solenoid valve set) assembly. The method involves the on-line photo-degradation of the analyte (stopped flow, 5 s) with the selected suitable medium (0.05% hydrogen peroxide) and its subsequent chemiluminescent oxidation by the potassium permanganate. Sample solution alternated segments with the photo-degradation medium; and, after the …
Enhanced nanoscopy of individual CsPbBr3 perovskite nanocrystals using dielectric sub-micrometric antennas
2020
We demonstrate an efficient, simple, and low-cost approach for enhanced nanoscopy in individual green emitting perovskite (CsPbBr3) nanocrystals via TiO2 dielectric nanoantenna. The observed three- to five-fold emission enhancement is attributed to near-field effects and emission steering promoted by the coupling between the perovskite nanocrystals and the dielectric sub-micrometric antennas. The dark-field scattering configuration is then exploited for surface-enhanced absorption measurements, showing a large increase in detection sensitivity, leading to the detection of individual nanocrystals. Due to the broadband spectral response of the Mie sub-micrometric antennas, the method can be e…
REATTORE E PROCEDIMENTO PER EFFETTUARE REAZIONI SELETTIVE
2015
La presente invenzione riguarda un reattore e un procedimento per eseguire processi di cristallizzazione reattiva con elevata selettività, consentendo di evitare la miscelazione diretta tra le due soluzioni contenenti i reagenti della reazione e di minimizzare l’effetto di reazioni secondarie indesiderate. Per brevità, nel testo seguente tale reattore e procedimento verrà indicato con l’acronimo CrIEM (Crystalliser with Ion Exchange Membrane).
Development of a specific assay using RISA for detection of the bacterial agent of 'basses richesses' syndrome of sugar beet and confirmation of a Pe…
2007
International audience; A technique for the specific diagnosis in insects of SBRp (the γ-3 proteobacterium associated with the syndrome ‘basses richesses’ (SBR) of sugar beet crops in eastern France), using the RISA (rDNA intergenic spacer analysis) technique, was developed. PCR using the Alb1/Oliv1 primer pair specifically amplified a 16S-ITS region of SBRp and produced a characteristic DNA fingerprint. This PCR assay did not detect other closely related organisms, including the Arsenophonus endosymbiont of Diaphorina citri, the secondary endosymbiont of Glycaspis brimblecombei, or ‘Candidatus Phlomobacter fragariae’, a related phytopathogenic γ-3 proteobacterium. Six different ribosomal o…
Innovative and Applied Research in Biology: Proceedings
2022
The collection contains SCIENTIFIC articles on the topics of the LU 80 conference reports. The main focus is on innovative and applied research in biology and interdisciplinary fields.
The pyrrole moiety as a template for COX-1/COX-2 inhibitors
2000
Aroyl- and thiophene-substituted pyrrole derivatives have been synthesized as a new class of COX-1/COX-2 inhibitors. The inhibition of COX-1 was evaluated in a biological system using bovine PMNLs as the enzyme source, whereas LPS-stimulated human monocytes served as the enzyme source for inducible COX-2. The determination of the concentration of arachidonic acid metabolites was performed by HPLC for COX-1 and RIA for COX-2. Variation of the substitution pattern led to a series of active compounds which showed inhibition for COX-1 and COX-2. Structural requirements for the development of COX-1/COX-2 inhibitors are discussed.