Dr Roberto Fernandez-Maestre, PhD - Universidad de Cartagena  - Analytical chemistry

Dr Roberto Fernandez-Maestre

PhD

Universidad de Cartagena

Analytical chemistry

Cartagena | Colombia

Main Specialties: Chemistry

Additional Specialties: Analytical chemistry

Dr Roberto Fernandez-Maestre, PhD - Universidad de Cartagena  - Analytical chemistry

Dr Roberto Fernandez-Maestre

PhD
Introduction

Primary Affiliation: Universidad de Cartagena - Cartagena , Colombia

Specialties:

Additional Specialties:


View Dr Roberto Fernandez-Maestre’s Resume / CV
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33

Publications

652

Profile Views

10

Reads

11

PubMed Central Citations

Experience
Feb 1997
Universidad de Cartagena, Colombia
Teaching Analytical Chemistry
Top co-authors
Herbert H Hill
Herbert H Hill

Washington State University

3
Ching Wu
Ching Wu

Purdue University

3
Robert Gordon Ewing
Robert Gordon Ewing

Washington State University

1

Publications

33Publications

10Reads

11PubMed Central Citations

Effect of particle size and oxidant concentration in the yield of humic acids from mineral coal using response surface methodology.

Rev. Acad. Colomb. Cienc. Ex. Fis. Nat. 41(160):361-369, julio-septiembre de 2017.

doi: http://dx.doi.org/10.18257/raccefyn.477

View Article
July 2017
3 Reads

Reduced ion mobilities of aspartame, cortisone, betamethasone, butylparaben, propylparaben and vanillin,

Int J Ion Mobil Spectrom 2017, 20(1), 11-13

Int J Ion Mobil Spectrom

https://doi.org/10.1007/s12127-017-0216-9

View Article
January 2017
3 Reads

Synthesis of 2,3-dihydro-1h-1,5-benzodiazepines containing the 8- hydroxyquinolinic fragment.

J Tche Quim.2017

J Tche Quim.

Benzodiazepines are used as anxyolytic, hypnotic, sedative and antidepressant drugs and to treat anxiety, insomnia, and epileptic seizures and show other types of biological activities. In this study, ten new 4(2)-(8-hidroxiquinolinil-5)-2(-4)-aryl-2,3-dihydro-1H-1,5-benzodiazepines and their rearrangement products, 2-substituted benzimidazoles, were synthesized from 1-aryl-3- (8-hydroxyquinolinil-5) propenone-1 (-3) and o-phenylenediamine in methanol-triethylamine (1:1) solution. The reaction between the diamine and chalcones containing the 8-hydroxyquinoline fragment was carried out under mild conditions by base-catalysis amination of the β-enonic fragment of the chalcones followed by cyclocondensation. The structures of these compounds were studied by spectroscopic methods (IR and 1H-NMR) and their chelating properties were demonstrated. We calculated and discuss their theoretical biological activity, and the influence of metal quelation on the electron acceptor hydroxyquinolinic fragment on the electronic spectra.

View Article
December 2016
6 Reads

Mobility shifts when buffer gas temperature increases in ion mobility spectrometry are affected by analyte's intramolecular bonds,

Int J Mass Spectrom 2016

Int J Mass Spectrom

When buffer gas temperatures increase in ion mobility spectrometry (IMS), ions lose hydration molecules and their mobilities increase. Also, when shift reagents (SRs, dopants or modifiers) are introduced into the buffer gas, ions form adducts with these SRs and their mobilities decrease. Some ions, such as methionine and diamines, are not largely influenced by the introduction of SRs or the buffer gas temperatures because they form intramolecular bonds. We used electrospray ionization IMS coupled to quadrupole mass spectrometry to study the drift behavior of these ions using data obtained at different temperatures or with different SRs. In this study, we explain the unusually small mobility shifts in methionine and diamine ions when buffer gas temperature increases in IMS based on the breaking of intramolecular bonds that increase the ions' collision cross-sections. We also explain the small mobility shifts in these ions when buffer gas SRs are introduced in the drift tube based on the formation of these intramolecular bonds. This study is important because when temperature increases in IMS, mobility shifts had been considered to be affected exclusively by declustering and the increase in collision frequency. This information will help understand the behavior of intramolecular bondforming ions in IMS at different temperatures and when buffer gas SRs are introduced in the drift tube, and could be used to demonstrate the presence of these bonds and measure their binding energy.

View Article
August 2016
4 Reads

Shift reagents in ion mobility spectrometry: the effect of the number of interaction sites, size and interaction energies on the mobilities of valinol and ethanolamine.

J Mass Spectrom 2016 May;51(5):378-83

Excellims Corporation, 20 Main Street, Acton, MA, USA.

View Article
May 2016
4 Reads
1 PubMed Central Citation(source)
2.38 Impact Factor

The adduction behavior of water reactant ions with mobility shift reagents in ion mobility spectrometry is determined by the number of locations for adduction, interaction energies, proton affinities, and steric hindrance of these species

Int. J. Ion Mobil. Spectrom. 2016, 19, 1-9 DOI: 10.1007/s12127-016-0199-y http://link.springer.com/

Int. J. Ion Mobil. Spectrom.

The introduction of mobility shift reagents (SRs) into the buffer gas of mobility spectrometers yields SR-ion clusters that decrease ion mobilities and allow the separation of overlapping ions. With a large amount of papers on the introduction of SRs in ion mobility spectrometry (IMS) few investigations explain the behavior of the adducts of reactant ions with SRs and it is not clear what type of peaks to expect which obscures the interpretation of spectra. Electrospray-ionization IMS was coupled to quadrupole mass spectrometry, and 2-butanol (B), ethyl lactate (L), and methanol were introduced as SRs into the buffer gas. The hybrid functional X3LYP/6–311++(d,p) with Gaussian 09 was used for theoretical calculations of SR-ion interaction energies. Adducts of the reactant ions with B and L presented different behaviors; even at low flow rates, L consumed all sodium, reactant ions, and water by adduction, because a) in the experimental conditions, SRs were more concentrated in the buffer gas than reactant ions, b) L’s high proton affinity and c) L’s three electron-donor oxygens, increases adduction. Therefore, chemical equilibria in the buffer gas were only between L and LnH+, LmH3O+, or LxNa+ adducts and, consequently, these sets of adducts had different mobilities. The lower mobility of LmH3O+ compared to LnH+ was explained on the base of the lower steric hindrance in LH3O+ for attachment of L molecules. The behavior of reactant ions with B was different: BnH3O+ and BnH+ overlapped because the relatively low proton affinity and the single and weaker interaction site in B allowed protons and water to be exchanged between species. Finally, L4H+, L4H3O+, B4H+ and B5H+ ions, not reported before, were seen for large SR concentrations. This study explains two different behaviors of the adducts of SRs with reactant ions using interaction energies, proton affinities, steric hindrance, and the number of locations for adduction.

View Article
April 2016
4 Reads

The charge-stripping Effect of tetrahydrofuran-2-carbonitrile Buffer Gas dopant in Ion Mobility Spectrometry

in evaluation

When dopants are introduced into the buffer gas of an ion mobility spectrometer, spectra are simplified due to charge stripping exerted by these molecules. We used electrospray ionization ion mobility spectrometry (IMS) coupled to quadrupole mass spectrometry to inject tetrahydrofuran-2-carbonitrile (F) as a buffer gas dopant. The density functional theory was used for theoretical calculations of dopant-ion interaction energies and proton affinities, using the hybrid functional X3LYP/6-311++(d,p) with the Gaussian 09 program that accounts for the basis set superposition error; analytes structures and theoretical calculations with Gaussian were used to explain the behavior of the analytes upon interaction with F. When F was used as a dopant at concentrations below 1.5 mmol m-3 in the buffer gas, ions were not observed for α-amino acids due to charge stripping by the dopant; this charge stripping capability arises from the production of a dimer with a high formation energy that stabilized the positive charge and created steric hindrance that deterred the equilibrium with analyte ions. F could not completely strip other compounds off their charge because they either showed steric hindrance at the charge site that deterred the approach of the dopant (2,4-lutidine, and DTBP), formed intramolecular bonds that stabilized the positive charge (atenolol), had high proton affinity (2,4-lutidine, DTBP, valinol and atenolol) or were inherently ionic (tetraalkylammonium ions). This selective charge stripping suggests the use of F to simplify spectra of complex mixtures in ion mobility and mass spectrometry in metabolomics, proteomics and other studies that generate complex spectra with thousands of peaks.

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December 2015
5 Reads

Activated carbons from waste of oil-palm kernel shells, sawdust and tannery leather scraps and application to chromium (VI), phenol, and methylene blue dye adsorption.

Water Science & Technology, 2015, doi:10.2166/wst.2015.293

Water Science & Technology,

Phenol, chromium, and dyes are continuously dumped into water bodies; the adsorption of these contaminants on activated carbon is a low-cost alternative for water remediation. We synthesized activated carbons from industrial waste of palm oil seed husks (kernel shells), sawdust, and tannery leather scraps. These materials were heated for 24 h at 600, 700 or 800 WC, activated at 900 WC with CO2 and characterized by proximate analysis and measurement of specific surface area (BET and Langmuir), and microporosity (t-plot). Isotherms showed micro and mesopores in activated carbons. Palm seed activated carbon showed the highest fixed carbon content (96%), and Langmuir specific surface areas up to 1,268 m2/g, higher than those from sawdust (581 m2/g) and leather scraps (400 m2/g). The carbons were applied to adsorption of Cr(VI), phenol, and methylene blue dye from aqueous solutions. Phenol adsorption on activated carbons was 78–82 mg/g; on palm seed activated carbons, Cr(VI) adsorption at pH 7 was 0.35–0.37 mg/g, and methylene blue adsorption was 40– 110 mg/g, higher than those from sawdust and leather scraps. Activated carbons from palm seed are promising materials to remove contaminants from the environment and represent an alternative application for vegetal wastes instead of their dumping into landfills.

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September 2015
5 Reads

Mobilities of amino acid adducts with modifiers in the buffer gas of an ion mobility spectrometer depended on modifier size and modifier-amino acid interaction energy.

Int J Mass Spectrom ISSN 1387-3806, 2015, 380, 21-25.

Int J Mass Spectrom

Buffer gas modifiers have been used to separate overlapping analytes in ion mobility spectrometry (IMS); separation relies on the formation of large and slow modifier-analytes adducts with different mobilities; however, it is unknown the cause of separation and predictions about a given separation cannot be made. Therefore, we vaporized phenylethanol modifier (P) into the buffer gas of an ion mobility spectrometer coupled to a quadrupole mass spectrometer to explain the selective effect of this modifier on the mobilities of asparagine, methionine, and phenylalanine amino acids; amino acid mobilities decreased selectively due to formation of slow phenylethanol:amino acid ion adducts. Mobility reductions were: asparagine (-19.4%), methionine (-19.5%), and phenylalanine (-20.8%). Then, we compared phenylalanine and methionine mobility reductions when 2-butanol (B), methyl 2-chloropropionate (M), and α-(trifluoromethyl)benzyl alcohol (F) modifiers were introduced in the buffer gas; mobility reductions were M> P> F> B for both amino acids. Parameters such as modifier size, modifier-ion interaction energies, modifier proton affinities, steric and inductive effects, and intramolecular hydrogen bond strength explained modifier effect on mobility reduction. High modifier-ion interaction energies increase adduct average lifetimes and large modifiers produce adducts with large collision cross sections, and explain mobility differences between adducts. The other parameters are taken into account when calculating modifier-ion interaction energies.

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April 2015
4 Reads

Separation of Asparagine, Valine and Tetraethylammonium ions Overlapping in an Ion Mobility Spectrometer by clustering with Methanol introduced as a Modifier in the Buffer Gas

just accepted with modifications

Anal. Meth

We introduced methanol into the buffer gas of an ion mobility spectrometer with an electrospray ionization source, coupled to a quadrupole mass spectrometer, and mobilities of selected compounds changed to different extents, depending on their structures, due to formation of slow ion-methanol clusters. This differential change in ion mobility was applied to the baseline separation of a mixture of valine, asparagine, and tetraethylammonium ions (TEA) that overlapped in the mobility spectrum; the drift time of TEA did not increase due to steric hindrance to attachment of methanol molecules to its positive charge by TEA´s four ethyl substituents; valine ion extensively clustered because its positive charge is more accessible for clustering with methanol and, therefore, its drift time increased the most, allowing resolution from TEA and asparagine; asparagine had an intermediate increase in drift time due to formation of intramolecular bridges that hid the positive charge from methanol molecules and delocalized it, for which asparagine had less clustering than valine. Other results show that when methanol concentration increased from 0.0 to 6.3 mmol m-3, changes in ion mobilities were: -5.0% (valine), -4.2% (phenylalanine), -3.2% (asparagine), -1.5% (glutamine), -1.4% (2,4-lutidine), -0.9% (arginine), -0.3% (2,6-di-tert-butylpyridine, DTBP), -0.2% (tetramethylammonium ion), and 0.0% (other tetraalkylammonium ions). Methanol in the buffer gas produced ion clusters with one to three methanol molecules in compounds with little steric hindrance in the charge as ethanolamine. The introduction of buffer gas modifiers has the potential of a tool for resolution of complex mixtures in ion mobility spectrometry.

View Article
December 2014
4 Reads

Explaining the Drift Behavior of Caffeine and Glucosamine After Addition of Ethyl Lactate in the Buffer Gas of an Ion Mobility Spectrometer.

Bull. Korean Chem. Soc. 2014, 35, 4, 1023- 1028. http://dx.doi.org/10.5012/bkcs.2014.35.4.1023. Impa

Bull. Korean Chem. Soc.

http://dx.doi.org/10.5012/bkcs.2014.35.4.1023. Impact Factor: 0.98/2014

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April 2014
5 Reads

Ammonia as a Modifier in Ion Mobility Spectrometry: effects on ion Mobilities and potential as a separation tool,

J. Chil. Chem. Soc., 59, 1, 2398 -2403 (2014).

J. Chil. Chem. Soc., 59, 1, 2398 -2403 (2014).

View Article
January 2014
4 Reads

Synthesis of 8-hydroxyquinoline chalcones: trans configuration, intramolecular hydrogen bonds, bromination, and antifungal activity.

J. Chil. Chem. Soc. 2012, 57, Nº 3, 1-5. Impact Factor: 0.38/2014; 0.65/5 años

J. Chil. Chem. Soc.

View Article
December 2012
3 Reads

Ion mobility spectrometry: history, characteristics and applications

Rev. U.D.C.A Act. & Div. Cient. (Colombia), 15(2), Dic. 2012, 467 – 479.

Rev. U.D.C.A Act. & Div. Cient. (Colombia),

Ion mobility spectrometry (IMS) is an analytical technique that separates ions in the gas phase. Ions are separated at atmospheric pressure under the influence of an electric field, according to their size and shape. IMS is the best choice for detection of narcotics, chemical and biological warfare agents and explosives in airports and customs. IMS can detect almost anything that can be ionized and has been applied to the analysis from the lightest elements such as helium to the most complex mixtures such as proteomes, metabolomes and complete organisms such as bacteria, chiral separations, and structure determination. Although since 2000 there have been approximately fifty reviews of IMS, this review is probably the only general valuation of this technique since then.

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December 2012
8 Reads

Buffer gas modifiers effect resolution in ion mobility spectrometry through selective ion-molecule clustering reactions.

Rapid Commun Mass Spectrom 2012 Oct;26(19):2211-23

Universidad de Cartagena, Programa de Química, Cartagena, Colombia.

View Article
October 2012
1 Read
3 PubMed Central Citations(source)
2.25 Impact Factor

Nitrobenzene as a Buffer Gas Modifier in Ion Mobility Spectrometry

Current Analytical Chemistry, 2012, 8,5, ISSN: 1573-4110

Current Analytical Chemistry, 2012, 8,5, ISSN: 1573-4110, Impact Factor 2013: 1.6

View Article
May 2012
4 Reads

Xanthated cation exchangers from colombian subbituminous Coal effectively removed lead and cadmium from aqueous solutions

Chemistry Today (Mexico), 2011, 1, 5, 23-25, ISSN: 0213-7828.

Chemistry Today (Mexico), 2011, 1, 5, 23-25, ISSN: 0213-7828

In Colombia, low rank coals are almost totally used for power and metallurgical aims,which are activities that produce contamination. In this investigation, as an altemative to the tnlditional use of low rank coals, we prepared cationic xanthated exchangers from a subbituminous coal (67.6% C, 4.6%H,22.4% O,0.6%S, 3.2% ashes and 46.2% volatile matter) of Montelibano-Córdoba; this exchanger showed better exchange capacities for cadmium and lead (1.8 meq/g) than traditional sulphonated exchangers (0.56 and 1.11 meq/g for cadmium and lead respectively). Xanthation was verified at 30 Cand at 5-10 °C with NaOH and CS2. The best performance of xanthation, determined by Infrared spectrometry and ion exchange experiments, occurred at low temperatures maybe due to CS, volatility. By diminishing the particle size of coal the exchange capacity increased. The exchange capacity was evaluated by flame atomic absorption spectrometry.

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January 2011
4 Reads

Using a Buffer Gas Modifier to Change Separation Selectivity in Ion Mobility Spectrometry.

Int J Mass Spectrom 2010 Dec;298(1-3):2-9

Department of Chemistry, Washington State University, Pullman, WA 9914, USA.

View Article
December 2010
3 Reads
4 PubMed Central Citations(source)
1.97 Impact Factor

Chemical standards in ion mobility spectrometry.

Analyst 2010 Jun 6;135(6):1433-42. Epub 2010 Apr 6.

Department of Chemistry, Washington State University, Pullman, WA 99164-4630, USA.

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June 2010
1 Read
3 PubMed Central Citations(source)
4.11 Impact Factor

Ion mobility spectrometry for the rapid analysis of over-the-counter drugs and beverages.

Int J Ion Mobil Spectrom 2009 Aug 1;12(3):91-102. Epub 2009 Jul 1.

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August 2009
1 Read

Hydrocarbon Contamination in Cartagena Bay Colombia.

Marine Pollution Bulletin ISSN: 0025-326X 44, 1, 71 - 81, 2001

Marine Pollution Bulletin

View Article
January 2001
5 Reads

The Pacific coast of Colombia

The Pacific coast of Colombia, in: Sheppard, C.R.C. (Ed.) (2000). Seas at the millennium: an environ

Seas at the millennium: an environmental evaluation:

The Colombian Pacific coast is characterized by a high precipitation during the whole year. It has two seasons: rainy and dry. The waters are relatively warm (from 25 to 26 degrees) with low salinity (from 20 o/oo near the coast and 33.5 o/oo at open sea). These conditions are altered periodically by El Niño phenomenon, which creates disorders in the climatic and oceanographic behavior. The tides in the Colombian Pacific coast are of semidiurnal type, from high mesotidal to macrotidal tendency and reach an approximate maximum amplitude of five meters. There are no hurricanes on the Pacific coast but there are ocassional tsunamis. The waves present heights from 0.5 to 2 m and intervals from 10 to 15 seconds. The coast drift is south-north. The population is distributed in 32 municipalities, mainly in urban centers such as Buenaventura and Tumaco. This region is the poorest in Colombia and it is severly underdeveloped. 40% of the 1.300 Kms of the Pacific coast is steep worked in igneous rocks northwards, and sedimentary rocks southwards. The remaining 60% is a low coast characterized by a great geomorphic variety. The coast line has a erosive tendency from very low to stable. The reefs are small-sized, discontinuous, low developed and subject to a high discharge from rivers. The Colombian Pacific coast is covered by extensive mangrove forests which main uses are: fishery, hunting, ecotourism and community recreation, elaboration of crafts, wood extraction (near 60% of the national market), subsistence agriculture and minor cattle activities. This is the area with highest vegetation coverage of the country. Of approximately 350.000 hectares that were estimated in the fifties, by the year 1973 some 281.300 hectares were left, 86% of which is considered has been intervened. The destruction of mangrove forests is due to the mentioned activities, a inadequate watershed management in the rivers and the growing contamination. In general, the quality of the Colombian Pacific waters is still not considerably affected by contamination which tends to be increased in time and space. The Colombian Pacific Ocean does not make part of the economic engagement of the country but foreign ships take advantage of the resources due to the lack of Coast Guards and a national fishing fleet. The fishing volume is maximum in May and minimum in October. The main species for fishery are prawns, shrimps, molluscs like oysters, mussels and clams. and fish like anchovy, tuna, bonito and sardine. The aquacultural production has increased. The Colombian commercial landings of marine species come mainly from the Pacific Ocean. The legislative framework for the management of fisheries is the 1990´s 13th Law. This law has established fishing quotas, regulation of fishing methods, reserve areas, bans and limitation of the fishing effort. There are three national parks in the Pacific Ocean: The Sanquianga, the Gorgona Island and the Utría Inlet. There are several international juridical instruments subscribed and many organisms to protect the environment http://www.marinespecies.org/imis.php?module=reflist&show=search&autid=7466 http://nmbl.org/cgi-bin/koha/opac-detail.pl?biblionumber=76848

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4 Reads

Cation exchange for mercury and cadmium of xanthated, sulfonated, activated and non-treated subbituminous coal, commercial activated carbon and commercial synthetic resin: effect of pre-oxidation on xanthation of subbituminous coal

Int J Coal Sci Technol (2014) 1(2):235–240 DOI 10.1007/s40789-014-0033-2.

Int J Coal Sci Technol

Abstract A subbituminous coal was oxidized with air at 150 C on a fixed bed for 4 h and xanthated with carbon disulfide in a basic solution, at 30 or 5–10 C. This xanthated coal was evaluated for the removal of Hg2? and Cd2? from 7,000 mg/L aqueous solutions; metal concentrations were determined by atomic absorption spectrometry. The ion exchange of the xanthated coal was compared against those of the original subbituminous coal, a sulfonated subbituminous coal, activated carbon, commercial activated carbon, and commercial synthetic resin. The commercial synthetic resin showed the highest exchange capacity (concentration factor 98 %) followed by the xanthated coal concentration factor 96 %). The retention of cadmium on the sulfonated subbituminous coal was lower (exchange capacity 0.56 meq/g) than that of xanthated coals (1.85 ± 0.09 meq/g). Our xanthated coal showed a better Cd2? removal (81 % against 15 %) than a non preoxidized 40-h-xanthated coal, which shows that oxidation of coal increased the amount of oxygenated groups which enhanced xanthation.

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4 Reads

Activated carbons from Sugar cane bagasse and corn cob for the adsorption of cadmium and lead.

Rev. Acad. Colomb. Cienc. 2011, 35, 136, 387-396.

Rev. Acad. Colomb. Cienc

Se prepararon carbones activados con bagazo de caña de azúcar (BC) y zuro de maíz (ZM) para adsorber cadmio y plomo. BC y ZM fueron carbonizados a 400°C por 1 hora, activados con ácido fosfórico y modificados con ácido nítrico o peróxido de hidrógeno y posterior calentamiento. La activación aumentó el área superficial de los carbones (5 m2/g a 778 m2/g para el ZM y 3 m2/g a 369 m2/g para BC). Los grupos oxigenados se analizaron por IR-DRIFTS. La acidez de los carbones estuvo entre 1.36 y 2.12 meq/g, el pH entre 2.9 y 6.5, y las capacidades de intercambio iónico hasta 0.070 meq/g (absorción atómica).

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4 Reads

Aluminum Contamination in blood and serum dialysates and prevalence of Aluminum-related Diseases in two Colombian hospitals

Rev Costarr Salud Pub 2013, 21, 2, 58-64, ISSN: 1409-1429

Rev Costarr Salud Pub

Objetivo: Se relacionó el grado de contaminación con aluminio en suero sanguíneo de pacientes sometidos a tratamientos de diálisis con el contenido de aluminio en los líquidos de diálisis que usaron estos pacientes y las alteraciones que mostraron en su salud. Método: Se analizaron por espectrometría de absorción atómica con horno de grafito (EAA) muestras de suero sanguíneo de 34 pacientes y dializados de dos instituciones hospitalarias de la ciudad de Cali-Colombia. Las muestras de suero se diluyeron 1:4 con el modificador (nitrato de magnesio y Triton X-100, al 1 %), y las de dializados se acidularon al 1,3 %. Resultados: Los pacientes del Hospital Universitario del Valle (desionizaba el agua para preparar el dializado), mostraron concentraciones de aluminio sérico menores (60 ± 20 mg L-1) que los del Instituto de Seguros Sociales (511 ± 96 mg L-1), donde no trataban esta agua. Los pacientes del Instituto presentaron una mayor incidencia de enfermedades relacionadas con el aluminio que los del Hospital. La exactitud del método analítico estuvo entre 99-101 % y los límites de detección fueron 1,5 para suero sanguíneo y 1,2 mg L-1 para dializados. Conclusión: Hubo una relación directa entre el contenido de aluminio en sangre y dializados con la frecuencia de enfermedades relacionadas con este metal.

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4 Reads

1,3,5-triaryl 2-pyrazolines with 8-hydroxyquinolinic substituent: syntheses, photophysical properties, and biological activity,

accepted

J Tche Quim. PERIÓDICO TCHÊ QUÍMICA • www.periodico.tchequimica.com

Background. 1,3,5-triaryl-2-pyrazolines are organic luminophores with arylic radicals that show a wide biological activity and are used as liquid scintillators and electro-optic materials. Experimental. Eleven 2-pyrazolines were synthesized from phenylhidrazine and chalcones of the 8-hydroxyquinoline series: 3-(8-hydroxyquinolin-5-yl)-1-(3-R)-phenylprop-2-enone and 1-(8-hydroxyquinolin-5-yl)-3--(3-R)-phenylprop-2-enone, where R = H, CH3, OCH3, N(CH3)2, Cl, Br, and NO2. The structures were confirmed by elemental analysis, IR, 1H-NMR, and electronic spectroscopy. Results and discussion. The 1- and 3- aryl substituents of the pyrazoline ring produced shifts to shorter or longer wavelengths, in absorbance and fluorescence. The electron acceptor hydroxyquinolinic fragment influenced the absorption and luminescence spectra; the possible cause of low quantum yields in pyrazolines 4а-g (1-phenyl-3-(4-R phenyl)-5-(8-hydroxyquinolinil-5)-2-pyrazoline) may be the specific intramolecular fluorescence quenching in bicromophores, characteristic of 5-acceptor substituted pyrazolines, and, in series 5а-g (1-phenyl-5-(4-R phenyl)-3-(8-hydroxyquinolinil-5)-2-pyrazoline) of excited-state intramolecular proton transfer (ESIPT) reactions, and the increasing donor-acceptor intramolecular interaction of their excited molecules; Density functional calculations (method PM6) were used to probe the electronic structure and energy ordering of the emissive and the electron-transfer states; PM6 results agreed with the experimental data. 1-phenyl-3-(4-R phenyl)-5-(8-hydroxyquinolinil-5)-2-pyrazoline showed fungistatic and fungicide activities. Additionally, all our pyrazolines showed wide theoretical biological activities.

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7 Reads

Total hydrocarbons in waters, superficial sediments and bioindicator bivalves in the Pacific Colombian Coast.

Mar Poll Bull 39, 9, 819-23,1999 http://dx.doi.org/10.1016/S0025-326X(99)00050-8

Mar Poll Bull

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5 Reads

Buffer gas temperature inhomogeneities and design of drift-tube ion mobility spectrometers: warnings for real-world applications by non-specialists,

Review of Scientific instruments, 2017, 88, 9, 096104

Review of Scientific instruments,

http://dx.doi.org/10.1063/1.5001845

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4 Reads

5. Fernandez-Maestre R. Accuracy of reduced mobilities and measurement of instrumental parameters in ion mobility spectrometry,

October 2017, 421, 8-13 Int J Mass Spectrom.

Int J Mass Spectrom.

https://doi.org/10.1016/j.ijms.2017.05.018

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3 Reads
Top co-authors
Herbert H Hill
Herbert H Hill

Washington State University

3
Ching Wu
Ching Wu

Purdue University

3
Robert Gordon Ewing
Robert Gordon Ewing

Washington State University

1