Eduardo Marchevsky | UNSL Universidad Nacional de San Luis (original) (raw)

Papers by Eduardo Marchevsky

Nutritional parameters of "mate cocido" with milk prepared from two species of Ilex and their com... more Nutritional parameters of "mate cocido" with milk prepared from two species of Ilex and their commercial mixture for school age population Parámetros nutricionales del "mate cocido" con leche preparado a partir de dos especies de Ilex y su mezcla comercial, para la población en edad escolar

Talanta, Mar 1, 1993

Reaction between pdolinium(II1) and 2-(S-hromo-2-pyridylazo)-S-diethylamitmphenol (5. Br-PADAP) w... more Reaction between pdolinium(II1) and 2-(S-hromo-2-pyridylazo)-S-diethylamitmphenol (5. Br-PADAP) was studied for delineating optimal conditions for complexation. This reagent can be used for the ~~ophoto~t~c determination of C%(III) in ~o~~tio~s ranging from 0.04 to 1.2 ppm (a = I.X(fO.f.S~ x I@ (I.-' mole-' j an]. The reaction takes plae at a pH between 9.2 and II.& In the presence of Trlton X-100 this complex is soluble in water. In order to overcome dilikultks caused by the presence of other lanthanides, an ion exchange chromatographic technique was used.

Anales De La Asociacion Quimica Argentina, Dec 1, 2006

The paper proposes a procedure for determination of lead in water samples by solid phase spectrop... more The paper proposes a procedure for determination of lead in water samples by solid phase spectrophotometry (SPS). It is based on the reaction of Pb(II) ion with 2-(5-Bromo2-pyridylazo)-5-(diethylamino)phenol (5-Br-PADAP) immobilized on an anion-exchange resin, that gives rise to a coloured complex, whose absorbance is measured directly in the solid phase. The method provides a detection limit of 2.4 µg L -1 and a sample throughput of 2 h -1 . The relative standard deviation (R.S.D.) was 1.7% for a Pb(II) concentration of 10.0 µg L -1 . The calibration graph obtained was linear with a correlation coefficient of 0.9995, in the range from the detection limit up to at least 100 µg L -1 . This method was successfully applied to the determination of Pb(II) in natural superficial waters from the Parana River in Argentina.

Analytical Sciences, 2011

Natural Products: An Indian Journal, Jun 1, 2010

Fresenius Journal of Analytical Chemistry, Nov 6, 2000

A simple and fast analytical pocedure is proposed for the simultaneous spectrophotometric determi... more A simple and fast analytical pocedure is proposed for the simultaneous spectrophotometric determination of lanthanum, holmium and manganese in synthetic ceramics, (La(0.8–x) Hox Sr0.2 MnO3), by using the partial least-squares (PLS) method. As chromogenic agent 5-Br-PADAP [2-(5-bromo-2-pyridylazo)-5-diethylaminophenol] was used, which form colored complexes with the three elements studied. To avoid metal hydrolysis, a mixture ¶of ethanol and Triton X-100 at

Instrumentation Science & Technology, Jul 1, 2005

Asociación Química Argentina, Oct 25, 2016

Journal of Environmental Hydrology Volume 10 Paper 4 July 2002 1 A graphical method is applied to... more Journal of Environmental Hydrology Volume 10 Paper 4 July 2002 1 A graphical method is applied to display the physical-chemical characteristics of the Miriñay River, Corrientes Province, Argentina. The graphical results show the following parameters: pH, alkalinity, chlorides, hardness, dissolved oxygen, N-ammonium, conductivity, and total dissolved solids. The graphical patterns allow easy identification and highlighting of water body characteristics. A PHYSICAL -CHEMICAL CHARACTERIZATION OF THE MIRIÑAY RIVER, ARGENTINA, BY GRAPHICAL METHODS

Introduction: "pearl fruit” or “Partridge herb" is a shrub that grows in South America ... more Introduction: "pearl fruit” or “Partridge herb" is a shrub that grows in South America where it is native. Infusions of the aerial parts: leaves and stems are used in folk medicine fundamentally for the treatment of several urinary disorders. No studies were found about of the mineral content of the aerial parts neither infusion for this species. Objectives: to determine the concentration of mineral elements in aerial parts and infusions of Margyricarpus pinnatus (Lam.) Kuntze. Methods: samples of M. pinnatus in San Luis, Argentina were collected. Concentrations of thirty-two elements in the aerial parts and infusions were determined by optical emission spectroscopy inductively coupled plasma. Results: concentrations in the aerial parts of twenty-four elements were found, while, at infusions only concentrations of fourteen elements were detected. The rest of the elements showed result below the limit of quantification. Extraction efficiency for the order Potassium> Calc...

Afinidad, 2006

Miel. PCA. Determinaciones. Interacciones.En el presente trabajo fueron evaluados los parametros ... more Miel. PCA. Determinaciones. Interacciones.En el presente trabajo fueron evaluados los parametros de las determinaciones analiticas de 23 muestras de origen natural de la Provincia de La Pampa (Argentina), utilizando analisis de componentes principales (PCA) como herramienta multivariada para la evaluacion y analisis de los resultados. Se realizaron las siguientes determinaciones analiticas: pH, humedad, contenidos de azucares reductores, sacarosa, HMF, acidez libre, acidez total y actividad diastasica de acuerdo a metodos oficiales. A traves de los resultados obtenidos mediante PCA, se pueden explicar fenomenos que ocurren sobre las variables estudiadas, tales como el comportamiento de la actividad diastasica, las interacciones entre HMF y acidez e interacciones entre sacarosa y azucares reductores, que permiten evaluarlas relaciones existentes entre las distintas variables analizadas.

Environmental Science: an Indian journal, 2010

In La Pampa,Argentina, soil bioremediation is one of the most widely used methods for the elimina... more In La Pampa,Argentina, soil bioremediation is one of the most widely used methods for the elimination of oil residues. Oil was treated with bacteria to degrade its organic compounds deposited in the soil. However, crude oil contains several transition elements, which can be accumulated in the soil after the bioremediation process is finished. For this reason, this paper discusses the determination of transition elements in bioremediated soils - including the concentration of Co, Cr, Cu, Fe,Mn,Mo, Ni, and Ti to evaluate its contribution to environmental impact in bioremediation zones from La Pampa, Argentina. The determinations of metals were carried out by inductively coupled plasma optical emission spectroscopy (ICP-OES) in soil samples proceeding from a remediation zone in the southwest of La Pampa. Testing samples without oil from the same zone were analyzed to determine the basal levels of elements. Results showthat oil has a contribution of transition elements and can be accumu...

Microchemical Journal, 2020

In this work, a novel low-cost and non-destructive method for true cinnamon authentication-based ... more In this work, a novel low-cost and non-destructive method for true cinnamon authentication-based on Nearinfrared diffuse reflectance spectroscopy and chemometrics-is presented. The use of cinnamon as a spice and flavouring agent is widespread throughout the world. Due to its high cost, true cinnamon-Cinnamon verum, which is only produced in Sri Lanka-it is adulterated with Cinnamon cassia due to its low commercial value. On the other hand, Cinnamon cassia contain a high content of coumarin (1%) which is a family of compounds containing 1,2-benzopyrone structures that are present only in minimal amounts in the barks of Cinnamon verum (0.04%). Due hepatotoxic effects of coumarin in animals and sensitive persons, the Food Safety Regulatory Agencies have imposed restrictions on the use of coumarin in their countries. Near-infrared diffuse reflectance spectroscopy (NIRS) and chemometric analysis were used jointly for evaluate adulterations of true cinnamon.

Journal of Chemometrics, 2020

Soybean (Glycine max (L.) Merril) is a popular foodstuff and crop plant, used in human and animal... more Soybean (Glycine max (L.) Merril) is a popular foodstuff and crop plant, used in human and animal food. In this work, multielement analysis of soybean grains samples in combination with chemometric tools was used to classify the geographical origins. For this purpose, 120 samples from three provinces of Argentina were analyzed for a panel of 20 trace elements by inductively coupled plasma mass spectrometry. First, we used principal component analysis for exploratory analysis. Then, supervised classification techniques such as support vector machine (SMV) discriminant analysis (SVM‐DA), random forest, k‐nearest neighbors, and class‐modeling techniques such as soft independent modeling of class analogy (SIMCA), potential functions, and one‐class SVM were applied as tools to establish a model of origin of samples. The performance of the techniques was compared using global indexes. Among all the models tested, SVM and SIMCA showed the highest percentages in terms of prediction ability ...

Microchemical Journal, 2018

Microchemical Journal, 2016

Tracing the geographical origin of Argentinean lemon juices based on trace element profiles using... more Tracing the geographical origin of Argentinean lemon juices based on trace element profiles using advanced chemometric techniques,