Search results for "quantitative analysis"
showing 10 items of 304 documents
Analytical Study of Raw Materials of Zinc Oxide Used for Enamels on Industrial Ceramics: Quantitative Analysis of Zinc, Lead, and Sulfur in These Sam…
2006
Abstract An analytical study is carried out to optimize X‐ray fluorescence (XRF) and flame atomic absorption spectrometry (FAAS) quantitative analysis of Zn, Pb, and S in ZnO samples commonly used to obtain industrial ceramic enamels. Pb and S in the raw materials often contaminate ZnO and are very detrimental in industrial applications. Thus, very accurate analytical determination of these elements in ceramic samples is extremely important. First of all, a mineralogical study by X‐ray diffraction (XRD) on the different components in these raw materials and the materials produced during the firing process is performed in order to establish the mineral forms in a reference sample for analysi…
Acute effects of low doses of methyl parathion on human EEG.
2005
Abstract Biological monitoring of workers exposed to organophosphates consists mainly of measuring serum or erythrocyte cholinesterase activity. However, animal experiments and a field study suggest that quantitative analysis of EEG may be more sensitive. In a parallel group design, 25 farmers were investigated, spraying methyl parathion or water for 50 min. EEG was recorded before and after spraying. Serum and erythrocyte cholinesterase activity was compared with intraindividual pre-exposure values. Plasma methyl parathion concentrations ranged up to 12.1 μg/l, methyl paraoxon was not detectable. Based on plasma concentrations, two exposed subgroups were defined. In EEG recorded with close…
Determination of Calcium in Certain Fertilizers by Inductively Coupled Plasma Atomic Emission Spectrometry: Studies of Some Spectral and Interelement…
1997
Abstract Four analytical wavelengths (393.366, 396.847, 317.933, and 422.673 nm) were used to determine Ca in 2 fertilizers by inductively coupled plasma atomic emission spectroscopy (ICP-AES). Matrix effects were studied by adding to real fertilizer solutions fertilizer elements that are known or believed to interfere with Ca determination. Matrix effects were calculated by multiple linear regression. Interference was caused by S, K, or B. At 422.673 nm, the interference of B and K is a spectral effect, and at 396.847 and 317.933 nm, the interference of S and K is an interelement effect. At 393.366 nm, no linear interference was found. The best wavelength for determining Ca in fertilizers …
Automated determination of clozapine and major metabolites in serum and urine.
1997
Clozapine is an atypical neuroleptic that is increasingly used for the treatment of schizophrenia. An automated method was developed for the routine quantification of clozapine and its major metabolites, N-desmethylclozapine and clozapine N-oxide, in human serum and urine by column switching and online high-performance liquid chromatography with ultraviolet detection. The method included adsorption of clozapine and its metabolites on a cyanopropyl-coated clean-up column (10 microns; 10 mm x 4.0 mm ID), washing interfering serum constituents to waste by deionized water, and, after column switching, separation on C18 ODS Hypersil reversed-phase material (5 microns; 250 mm x 4.6 mm ID). The co…
Determination of Phenylephrine Hydrochloride by Flow Injection Analysis with Chemiluminescence Detection
2001
Abstract A new method is proposed for the determination of phenylephrine hydrochloride by flow injection analysis with direct chemiluminescence detection. The method is based on the oxidation of the drug by potassium permanganate in sulfuric acid medium at 80°C. The calibration graph is linear over the range 0.03–8 ppm phenylephrine hydrochloride, with a relative standard deviation (n = 51, 0.5 ppm) of 1.1% and sample throughput of 134/h. The influence of 38 different foreign compounds was tested, and the method was applied to the determination of phenylephrine hydrochloride in 8 different pharmaceutical formulations.
Determination of Magnesium in Fertilizers by Inductively Coupled Plasma Atomic Emission Spectrometry: Studies of Some Spectral and Interelement Effec…
1995
Abstract Four analytical wavelengths of magnesium were tested for determination of Mg from fertilizers by inductively coupled plasma atomic emission spectroscopy (ICP-AES): 202.528, 285.213, and 383.826 nm (Mg I) and 279.553 (Mg II). The effects of fertilizer matrix elements on Mg determination were examined by adding matrix elements to fertilizer solutions. Multiple linear regression calculations proved a valuable technique for evaluating the effects of matrix elements on Mg determination. The observed interferences at Mg wavelengths may be both spectral and interelement. Interelement effects were typically caused by Na, K, and Ca, and spectral effects, by P, Fe, and S. The best wavelength…
Kinetische Analyse der Calcium-Kompartimente im Meerschweinchenherzen unter Kontrollbedingungen und Strophanthineinwirkung
1974
A quantitative analysis of myocardial Ca-metabolism was carried out on isolated, isovolumetric (10 ml/min) perfused guinea pig hearts by combined determinations of the total Ca-content and kinetics of 45Ca-efflux (collecting period 60 min) (Fig. 1). The kinetics of 45Ca-uptake was estimated by extrapolating 45Ca-efflux curves of heart muscles isotopically loaded for different times (2, 5, 10, 30 60 min) to the end of the loading-period (Fig. 2).
Enhanced chemiluminescent determination of chloramphenicol and related nitro compounds by ‘on-line’ photochemical reaction
2000
The viability of tandem photochemical reaction-chemiluminescence detection was studied for a heterogeneous family of nitro compounds using chloramphenicol as a test substance. The 'on-line' chemical photodegradation of chloramphenicol was performed in a flow injection assembly by using a photoreactor consisting of a 725 cm x 0.5 mm id piece of PTFE tubing coiled around an 8 W low-pressure mercury lamp. Photodegraded chloramphenicol was detected by oxidizing photo-fragments from the parent compound and their subsequent reaction with a luminol-Co(II) system. The calibration graph was linear up to 3 x 10(-5) mol l-1 chloramphenicol, the limit of detection was 3 x 10(-9) mol l-1, the relative s…
A quantitative analysis of university student reasoning lines in the field of thermally activated phenomena
2018
In this contribution we present a research aimed at studying the effectiveness of two workshops in improving reasoning skills in undergraduate students. Both the workshops are based on the Feynman Unifying Approach. A questionnaire containing six open-ended questions on the temperature dependence of evaporation of a liquid and of a chemical reaction was administered to the students of both groups before instruction. A second one, similar to the first but focused on a physical content different from both the pre-instruction test one and the content dealt with during the workshops, was administered after instruction. The responses to the pre- and post-instruction questionnaires are analyzed b…
A quantitative analysis of wild herbaceous plant species for medicinal uses in four Regional Parks in Sicily (Italy)
2019
This paper illustrates the results of a study carried out in 4 regional Parks in Sicily (Italy) from 2009 to 2010. The study area covers a surface of 2076 km2, the 8% of the territory of Sicily, includes 90 towns and it is characterized by a high degree of plant biodiversity. The main aim of the study was to analyse the extent of the current knowledge on medicinal uses of wild shrub and herbaceous plants in the area, using quantitative indices. The information was obtained using semi-structured interview format performed on a sample of 802 people over the age of 60 who were considered experts in rural traditions. The results highlight that most of the species are used against general health…