Search results for "Quantitative analysis."
showing 10 items of 304 documents
FIA-fluorimetric determination of adrenaline by oxidation with a solid-phase reactor of manganese dioxide incorporated in polyester resin beads
1995
Abstract The FIA-spectrofluorimetric determination of adrenaline was carried out by reaction of the drug with manganese dioxide entrapped in a polymeric material in a solid-phase reactor; the oxidized drug was monitored fluorimetrically at 540 nm (Ioxg. 330.0 nm). The calibration graph for adrenaline was linear over the range 0.5 - 20 μg ml−1 with a relative standard deviation of 2.0% (at 5 ug ml−1) and the sample throughput of 65 h−1. The influence of foreign compounds was studied and the method was applied to the determination of adrenaline content in a pharmaceutical formulation . ∗Present address: Institut of Chemistry, Warsawa University, Bialystok Branch, Bialystok, Poland.
Flow injection biamperometric determination of metronidazole with on-line photodegradation
1999
Abstract The determination of metronidazole is performed in a flow injection assembly, provided with a 40 W low pressure mercury lamp and a home-made biamperometric flow-cell furnished with two platinum electrodes polarized at 100 mV. The sample solution after being irradiated is inserted into a pure water stream. It then merges with an in situ mixed solution containing potassium iodide in sulphuric acid. The calibration graph was linear over the range 0.2–8.0 mg l −1 metronidazole; the 3 σ limit of detection was 0.008 mg l −1 ; the relative standard deviation was 0.6% (for 4 mg l −1 n = 13) and the sample throughput 50 h −1 . The influence of foreign compounds is slight and the method is …
Flow injection-FTIR determination of dithiocarbamate pesticides
2000
A flow injection Fourier transform infrared spectrometric procedure has been developed for the determination the dithiocarbamate pesticides Ziram and Thiram in solid samples. All the operations involved, such as extraction, filtration and measurement, were integrated in the experimental set-up in order to avoid excessive manipulation of samples and standards. Ultrasonic assisted and mechanical extraction were evaluated for the solubilization of the analytes and, additionally, the effect of carrier flow rate, sample loop volume and the ratio between sample mass and volume of solvent employed were studied. Quantitative extractions with chloroform were obtained for both Ziram and Thiram, after…
Qualitative and quantitative thermoluminescence analysis on irradiated oregano
2007
Abstract Thermoluminescence (TL) dosimetry is one of the physical methods used for the identification of irradiated food, suitable for foods from which silicate minerals can be extracted. The aims of the present work were to apply the TL analysis for a qualitative identification of irradiated oregano, and to set up a quantitative procedure to estimate the original treatment dose on the sample. The experimental results show that the TL analysis allows to distinguish irradiated oregano even seven months after the treatment. The additive dose procedure gives a rough estimation of the treatment dose, but can be helpful when the TL ratio method is unsatisfactory.
Comparison of extraction and clean-up procedures for analysis of zearalenone in corn, rice and wheat grains by high-performance liquid chromatography…
2002
The aim of this work was the optimization of some procedures usually used in the analysis of zearalenone (ZEA) in corn and other cereals by high-performance liquid chromatography (HPLC) with photodiode array and/or fluorescence detection. The comparison of five extraction solvents is presented. Three solid-phase extraction cartridges (C-18, silica, Florisil) and immuno-affinity columns were also compared to obtain the best recovery of the mycotoxin with the minimal presence of co-extractives in the chromatograms. Mixtures of methanol-1% aqueous NaCl (80.20 or 60:40 v/v) were the best extraction solvents. Florisil provided higher recovery of ZEA than C-18, and silica proved unsuitable. The i…
A Quantitative Analysis of Metrics on Rn with Almost Constant Positive Scalar Curvature, with Applications to Fast Diffusion Flows
2017
We prove a quantitative structure theorem for metrics on $\mathbf{R}^n$ that are conformal to the flat metric, have almost constant positive scalar curvature, and cannot concentrate more than one bubble. As an application of our result, we show a quantitative rate of convergence in relative entropy for a fast diffusion equation in $\mathbf{R}^n$ related to the Yamabe flow.
Control cuantitativo de la calidad en una empresa del sector servicios = Quantitative quality control in a company of the service industry
2013
<p>En el presente trabajo se aplican herramientas de Control Estadístico de Calidad, habitualmente utilizadas en procesos productivos, a una empresa dedicada a la auditoría y que por tanto pertenece al sector servicios. La elección de las herramientas utilizadas (gráficos de control, indicadores de capacidad, función de pérdida de Taguchi…) obedece a la necesidad de controlar si se cumple el objetivo de la empresa de realizar la auditoría a la empresa cliente 7 días antes de la fecha teórica, lo que conlleva una disminución de costes. También se cuantifica la pérdida que produce el incumplimiento de dicho objetivo y se proponen medidas correctoras que disminuyen la variabilidad del pr…
Assays for Detection of Fungal Hallucinogens Such as Psilocybin and Psilocin
2016
Abstract Methods applicable to the detection of hallucinogenic indole compounds, namely psilocybin, psilocin, and related molecules, that have been developed so far for purposes of mycological research, toxicological studies, or forensic investigations are described in this chapter. The most current literature as well as some interesting older publications are cited, providing a historical overview of the subject. Methods of qualitative and quantitative analysis are presented. Additionally, preliminary purification steps and sample treatment before the exact quantitative determination are proposed. The methods described utilized various analytical techniques for the measurement of psilocybi…
Different approaches to research and innovation in physics education at college and university
2019
Abstract In this article we report a Symposium organized by GTG-Physics Education Research at University (PERU) with different proposals that includes innovative educational approaches and research on problems of teaching-learning physics at university. In the second section, two research projects are described on teaching specific curriculum topics that present special difficulties for students. In the next section the third project on a work experience in the laboratory that takes into account the characteristics of scientific work, is presented. Finally, the fourth project presents a way to investigate the types of student reasoning. In the discussion, the importance of research projects…
Comparison of LIBS and micro-XRF measurements on bronze alloys for monitoring plasma effects
2011
The laser-induced breakdown spectroscopy (LIBS) technique is often used as atomic spectroscopic technique for elemental analysis of materials. However, it presents some drawbacks that make an accurate quantitative analysis difficult. Since the plasma properties, such as spatial inhomogeneity and plume stoichiometry strongly depend on the experimental conditions, the measurements are less reproducible. In order to evaluate the measurement fluctuations, we propose to use the more established micro X-Ray fluorescence (μ-XRF) technique for validating LIBS data. In particular, the quantitative data, obtained by varying the laser fluence, the shot numbers and the temporal acquisition parameters, …