Search results for "metan"
showing 10 items of 60 documents
Simultaneous Kinetic Determination of Carbamate Pesticides after Derivatization withp-Aminophenol by Using Partial Least Squares
1996
Abstract A method has been developed for the fast spectrophotometric determination of propoxur, carbaryl, and ethiofencarb in water samples using injection analysis in the stopped-flow mode. The method is based on the reaction between p -aminophenol and the phenolic compounds obtained from the pesticides, after a previous hydrolysis with 0.05 M NaOH at room temperature for 15 min. The partial least-squares treatment of the spectrophotometry kinetic data provides a simultaneous determination of the three carbamate pesticides assayed with a relative accuracy error lower than 5% in complex mixtures also containing formetanate, which is only partially hydrolyzed under the experimental condition…
Detection of banned drugs in sport by micellar liquid chromatography
1992
Abstract A rapid method for the determination of banned drugs in sport (including stimulants, anabolic steroids and diuretics) based on micellar liquid chromatography is proposed. The mobile phase is an aqueous solution of a surfactant (sodium dodecyl sulphate in this instance) and the stationary phase is octadecylsilica. The retention parameters of the drugs were established and the effect of a mobile phase organic modifier on the chromatographic behaviour of the compounds was studied. Improvements in efficiency were achieved by control of the temperature of the mobile phase. This method allows the direct injection of urine samples for the determination of drugs excreted free in urine: ami…
Spectrophotometric flow injection determination of formetanate and m-aminophenol in water after reaction with p-aminophenol
1992
Abstract An automated procedure has been developed for the determination of formetanate and its metabolite m -aminophenol (MAP) in water samples. MAP can be selectively determined in the presence of formetanate by direct on-line reaction with p -aminophenol and spectrophotometric measurement of the absorbance at 576 nm in the presence of KIO 4 , as oxidizing agent. The method has a limit of detection of 5 × 10 −7 M , it provides a recovery percentage from 95 to 104% and permits one to carry out 120 measurements/hr. The spectrophotometric determination of formetanate must be carried out after a previous hydrolysis to MAP. To determine formetanate in the presence of MAP, two steps are necessa…
Rapid microwave assisted hydrolysis of formetanate
1993
Abstract A fast microwave-assisted hydrolysis procedure has been developed for the derivatization of formetanate previously to the flow-injection spectrophotometric determination of m -aminophenol by reaction with p -aminophenol. Formetanate is quantitatively hydrolyzed with 0.1 M NaOH in 150 s using a closed polyetrafluoroethylene reactor with 115 ml internal volume and a radiation power of 390 W. The above procedure has been applied, as a previous step, for the flow-injection spectrophotometric determination of formetanate in spiked water samples and accurate and precise results have been found. The method permits to obtain a limit of detection of 0.025 mg 1 −1 of formetanate. The relativ…
Oral manifestations in drug users : a review
2020
Background: In the dental environment there is not much talk about the oral manifestations resulting from the use of drugs, because in general the issue of drugs is a very difficult subject to deal with. Therefore, the objective of this work is to understand what are the most obvious manifestations in the oral cavity and as the dentist can detect them. Material and Methods: In order to carry out this bibliographical review, a scientific article search was made by consulting the PubMed database. The abstracts were read to recruit only what was consistent with the chosen topic. Results: The 23 sources of information affirmed the relationship between a bad state of general health, and more in …
Influenza della copertura superficiale sulle emissioni diffuse di metano da discarica: analisi di casi studio
2015
La quantizzazione delle emissioni di CH4 da discariche rappresenta un tema di rilievo nella gestione dei rifiuti. La capacità emissiva delle discariche, direttamente correlata alla decomposizione anaerobica della sostanza organica in esse smaltita, può durare per decine di anni sebbene la massima produzione di biogas si registra nei primi anni seguenti l’abbancamento dei rifiuti. Nella nota si riferisce dei risultati di alcune campagne di misura eseguite su discariche controllate per rifiuti urbani, dotate di differente tipo di copertura; in particolare, la prima discarica è dotata di capping definitivo, la seconda di capping temporaneo. I risultati ottenuti hanno evidenziato una significat…
Indoor and outdoor determination of pesticides in air by ion mobility spectrometry.
2016
Abstract The use of ion mobility spectrometry (IMS) has been evaluated as analytical methodology to detect and evaluate the occupational exposure to pesticides. The developed IMS methodology was used, in positive and negative modes, to determine the presence of pesticides in air and to evaluate possible inhalation exposures of workers and users based on active sampling on Teflon membranes and direct thermal desorption IMS. The negative IMS mode was used to determine bensulfuron, clorpyrifos, diniconazole, diuron, flutolanil and imidacloprid, while the positive mode was employed to evaluate formetanate, metalaxyl, metamitrone, metribuzin, paclobutrazol and pirimicarb. The IMS measurements pr…
Metanola noteikšana ar eksprestestu metodi
2019
Metanola noteikšana ar eksprestestu metodi. Milekhina N., zinātniskais vadītājs Dr. chem., doc. Ģībietis J. Bakalaura darbs, 57 lappuses, 28 attēli, 14 tabulas, 76 literatūras avoti. Latviešu valodā. Darbā apkopota informācija par metanola izmantošanu, tā ietekmi uz cilvēka organismu, tā noteikšanu ar kvantitatīvās analīzes metodēm. Eksperimentāli iegūts kalibrēšanas grafiks spektrofotometriskai metanola noteikšanai ar hromotropskābi un spektrofotometriskai noteikšanai ar p-nitroanilīnu. Aprobēta ekspresmetode metanola noteikšanai alkoholiskos dzērienos un izveidots testkomplekts šī uzdevuma veikšanai.
Metanarrative of the "New Father" and Narratives of Young Finnish First-Time Fathers
2011
The metanarrative of the “new father” has become well-established in both the public and academic discourses on families. This study analyzes the narratives and storylines about fatherhood told by young Finnish first-time fathers, and examines the interrelationship between these narratives and the metanarrative of the “new father.” Three different narratives were identified—the modern, the transition and the postmodern narratives of fathering. Although constructed differently, all three narratives engaged with the metanarrative of the new father by reflecting on it and by drawing a distinction between their perceptions of fatherhood and the narratives of the past. In conclusion, the idea of…
Pathology-selective antiepileptic effects in the focal freeze-lesion rat model of malformation of cortical development
2021
Malformations of cortical development (MCD) represent a group of rare diseases with severe clinical presentation as epileptic and pharmacoresistant encephalopathies. Morphological studies in tissue from MCD patients have revealed reduced GABAergic efficacy and increased intracellular chloride concentration in neuronal cells as important pathophysiological mechanisms in MCD. Also, in various animal models, alterations of GABAergic inhibition have been postulated as a predominant factor contributing to perilesional hyperexcitability. Along with this line, the NKCC1 inhibitor bumetanide has been postulated as a potential drug for treatment of epilepsy, mediating its antiepileptic effect by red…