Anca-Iulia Stoica

Differential pulse cathodic stripping voltammetric determination of selenium in pharmaceutical products

The aim of this paper is to determine selenium from pharmaceutical products by differential pulse cathodic stripping voltammetry. Firstly, were established the optimum parameters for voltammetric determination of selenium (electrolyte, deposition time, pulse duration, pulse amplitude, etc.) and secondly, the content of selenium was determined in five pharmaceutical products. The drug samples were treated with a mixture of 6 ml HNO(3) and 1 ml H(2)O(2) in the microwave oven. Due to the matrix effects the method of addition is preferred. The peak potential is -0.545 V vs. Ag/AgCl, and the calibration curve is linear up to 0.125 ng/ml, but selenium was determined from pharmaceutical products used the calibration curve in the range 8-64 ng/ml, due to the concentration of selenium in these tablets.

Determination of Copper, Cadmium, Zinc And Lead In ArgeŞ River In Romania During Four Seasons By Inductively Coupled Plasma Atomic Emission Spectrometry And Anodic Stripping Voltammetry

ABSTRACT The paper represents a continued study of selected heavy metals concentration in the Argeş River, the fifth river in length from Romania. For the determination of metal ion concentration in Argeş river was used Atomic Absorption Spectrometry for sodium, potassium and magnesium; Direct Coupled Plasma Atomic Emission Spectrometry for calcium; Inductively Coupled Plasma Atomic Emission Spectrometry for copper, cadmium, zinc, aluminium, lead, titanium, zirconium, chromium, molybdenum, manganese, iron and nickel. Copper, cadmium, zinc and lead concentration were determined by ICP–AES and ASV and results were reliable. By comparison of the results a good agreement between these two techniques is observed.

Differential Pulse Voltammetric Determination of 8‐Aminoquinoline Using Carbon Paste Electrode

Abstract This paper describes the differential pulse voltammetric determination of 8‐aminoquinoline using carbon paste electrode. The optimum parameters for this determination were established (supporting electrolyte, pH, time of accumulation). In 0.1 mol · dm−3 H3PO4, it is possible to determine 8‐aminoquinoline down to 2.10−6 mol · dm−3 by differential pulse voltammetry. And, 0.1 mol · dm−3 NaOH enables us to achieve the limit of determination 2.10−7 mol · dm−3 using adsorptive stripping voltammetry. The possibility of determining 8‐aminoquinoline in the presence of 5‐aminoquinoline was also investigated. This research was supported by the Grant Agency of the Czech Republic (grant no. 203/03/0182).

Analytical studies on the pollution of argeş river

Using two analytical techniques (ICP‐AES and ASV) the heavy metal pollution of Argeş River was studied. These techniques are characterized by similar analytical performances. The samples were collected from 13 sites starting from Capra Lake (altitude 2241 m) and finishing at Oltenita city (altitude 10 m). Argeş River is the fifth longest river in Romania after Siret, Mureş, Olt and Someş, its length is 340 km and the river flows through four cities, Curtea de Argeş, Piteşti, Gaeşti and Oltenita. The results of the determinations of Cu, Cd, Zn and Pb, indicate that the Argeş River shows relatively low pollution.

Voltammetric and amperometric determination of 2,4-dinitrophenol metabolites

Methods for determination of 2-amino-4-nitrophenol and 4-amino-2-nitrophenol, metabolites of 2,4-dinitrophenol, were developed using differential pulse (DP) voltammetry and HPLC with amperometric and spectrophotometric detection. The applicability of these methods was tested by the determination of the analytes in model samples of urine after preliminary separation by solid-phase extraction. Voltammetry enabled parallel determination of both analytes, but its application in real matrix was severely limited due to the interference of other compounds present in urine. HPLC allowed the determination in real urine matrix down to micromolar concentrations; amperometric detection proved to be more sensitive and selective than the spectrophotometric one.

Analytical contributions to the evaluation of painting authenticity from Princely church of Curtea de Arges.

The present study contains the analyses performed for pigment samples taken from the Princely church of Curtea de Arges, one of the oldest churches in Romania. The results of our investigations have shown the source of these samples, thus being identified the pigments: natural ultramarine, cinnabar, red earth, and calcium carbonate in the painting from the 14th century, the pigments: lead white, zinc white, and Prussian blue in the repainting from the 19th century and the pigments zinc white, titanium dioxide white, bone white, yellow ochre, red ochre, green earth, artificial ultramarine, and mars red in the interventions carried out in the 20th century. The analyses consisted of light microscopy (LM) and microchemical tests, as well as energy dispersive X-ray (EDX) analysis. This system of analyses allows one to precisely determine the authenticity of certain pigments, thus avoiding the dating errors for different interventions carried out on the original mural painting from the Saint Nicholas Princely church of Curtea de Arges.

Analytical Studies on the Pollution of Arges River

The Arges River arises from the ice lake Capra, which is situated in the Fagaras mountains, and is flows into the Danube River near Oltenita city. During this “trip” it collects, more or less cleaned, industrial or home-originated wastewater and other waste materials. Some of these are deposited on the river bed, others are transported downstream by water or fish. Among antropogenic compounds, heavy metal ions may be the most harmful pollutants. While many other compounds are more or less biodegradable, heavy metal ions could be retained in the ecosystem, indefinitely. The water samples were collected between Cumpana and Oltenita from 12 sites placed in the middle of the stream. Heavy metal ions concentration in the samples were quantified by Atomic Absorption Spectrometry and by Inductively Coupled Plasma Atomic Emission Spectrometry. The values were compared with Anodic Stripping Voltammetry delivered results (Cu, Cd, Zn, Pb), which provided a good agreement. The values determined within our work repres...

Kemula, Pungor, and Guilbault Creators of New Fields in Analytical Chemistry

The present paper proposes to discuss the contributions of Kemula, Pungor, and Guilbault to the field of Analytical Chemistry. Their studies established new fields of Analytical Chemistry as Anodic Stripping Voltammetry (ASV), Ion Selective Electrodes, and Enzymatic Methods of Analysis. These techniques are characterized by high sensitivity and a good selectivity.

George-Emil Baiulescu: The Senior of Romanian Analytical School 1931–2009

George-Emil Baiulescu was born in Transylvania on August 4, 1931, between the two World Wars and into a famous family, which included lawyers and priests. He received a strong education from family and the capacity to appreciate the values of life. He studied at the Faculty of Chemistry, University of Bucharest and obtained his B.Sc. in 1954, Ph.D. title in 1960, D.Sc. in 1970, and in 1971, he received the authorization to direct Ph.D. students. Beginning in 1958, George-Emil Baiulescu was an assistant, lecturer, reader, and professor at the Faculty of Chemistry. In 1961, Professor George-Emil Baiulescu, together with Professor Grigore Popa, founded the Department of Analytical Chemistry from the Faculty of Chemistry, University of Bucharest. His research, developed over half a century, started with organic reagents used for different ion determination, followed by environmental studies, ion selective electrodes, separation methods, atomic absorption, emission spectrometry, molecular emission spectrometry, chromatographic techniques. One of the most important fields in which Professor Baiulescu contributed was sampling. He considered that the ‘‘Sampling process consists of many preliminary steps before measurement, including separation.’’ His research has been published in more than 200 papers in important industry journals such as Analytical Chemistry, Talanta, Trends in Analytical Chemistry, Analytica Chimica Acta, Critical Reviews in Analytical Chemistry, Analyst, Analytical Letters, Mikrochimica Acta, etc. Professor George-Emil Baiulescu published his ideas and knowledge in books in Romanian publishing houses: in 1974, ‘‘Physical Methods of Trace Analysis’’ in Editura Tehnică, Bucharest; in 2004, ‘‘Environmental Analytical Chemistry. Concepts’’ through Ars Docendi; and in foreign publishing houses: ‘‘Stationary Phases in Gas Chromatography’’ in 1975, published by Pergamon Press, Oxford; ‘‘Applications of Ion Selective Membrane Electrodes in Organic Analysis,’’ in 1977 published at Ellis Horwood, translated in 1980, also in Russian, Mir-Moscow; ‘‘Education and Teaching in Analytical Chemistry,’’ in 1982, published at Ellis Horwood, Chichester and translated in China, 1993; ‘‘Sampling’’ in 1991; and one chapter in Gold Mining: Formation and Resource Estimation, Economics and Environmental Impact, ‘‘The Influence of Gold Mining Industry on the Pollution of Roşia Montana District,’’ through Nova Publishers House, 2009. Analytical Letters, 43: 1254–1256, 2010 Copyright # Taylor & Francis Group, LLC ISSN: 0003-2719 print=1532-236X online DOI: 10.1080/00032711003707928

Green Chemistry—Correlation Between Cause and Effect: A Guest Editorial

Abstract Green chemistry represents an actual tendency to improve the quality of different kinds of technologies used in chemical industries. It represents an improvement of chemical engineering to develop unpolluted systems for producing various kinds of chemicals. The development of this idea is due to the studies on environmental pollution of air, water, and soil, using up‐to‐date analytical techniques. It represents a perfect correlation between chemical technologies (cause) and analytical techniques (which study the pollutants, effects). In these conditions is imposed a perfect cooperation between technologist and system analyst to assure an improvement, step by step, of chemical production.