Marcos N Eberlin

National Institute of Metrology, Quality and Technology (Inmetro), Rio de Janeiro, Rio de Janeiro, Brazil

Are you Marcos N Eberlin?

Claim your profile

Publications (692)2006.07 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: This work evaluated the effect of electron beam irradiation (E-beam) on sugarcane juice and compared the results with preliminary tests performed on sugarcane juice treated with gamma irradiation. The samples were irradiated at 5, 10 and 20 kGy doses and results were compared wile control samples without irradiation. The results showed a significant increase (p≤0.05) of phenolic compounds in both treatments. We also observed increased contents of reducing sugars (glucose and fructose) for the samples irradiated with gamma rays and E-beam measured by the DNS methods. However, there was no significant difference of sugars content measured by chromatographic analyses performed in the sugarcane juice treated with E-beam. Therefore reducing sugars content could be overestimated by the DNS method because salts in sugarcane juice. The treatments were able to reduce sugarcane juice ICUMSA color intensity in both treatments with irradiation. E-beam reduced sugarcane juice color by roughly 49% compared the control, while gamma irradiation reduced it by 30%.
    No preview · Article · Apr 2016
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The Itajaí-Açu estuarine region is one of the most important estuarine systems of south Brazil, due to the location of the Itajaí Harbor, which is the major route of international trading of the state and the largest national fishing pole landing. In addition, industries as well as urban and tourism activities are potential sources of pollution in this area. In the present study, sediment samples from 12 stations along the estuarine system were collected and extracted followed by ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) analysis. Eight sterols were identified and quantified, indicating natural and anthropogenic sources. Coprostanol concentrations ranged from <4 up to 8930ngg(-1) of dry weight sediment with higher values being observed in the area next to the Itajaí Harbor and under influence of Itajaí-Mirim River flow, which receives wastewater from several cities. Concentrations and selected sterol ratios were useful tools used to distinguish anthropogenic and biogenic organic matter (OM) sources in the studied area, where coprostanol concentrations higher than 500ngg(-1) were observed in 42% of the stations analyzed, indicating strong sewage contamination. Factor analysis with principal component analysis (FA/PCA) has distinguished two different groups of samples, with high and low total sterol concentrations. FA/PCA results revealed that the stations located in the estuary were separated by PC1 because they are clearly contaminated by sewage, also pointed by coprostanol/(coprostanol+cholestanol) and coprostanol/cholesterol ratios and by the higher concentrations of fecal sterols.
    Full-text · Article · Feb 2016 · Science of The Total Environment
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this study we modeled the in vitro antibacterial activity of the extracts of green, white and black tea mixtures using the response surface methodology. Camellia sinensis var sinensis tea mixtures were prepared according to a 3-component simplex-centroid design containing ten formulations. The antibacterial activity was used to assess the inhibition ability of the tea mixtures against a range of seven Gram positive, Gram negative, vegetative cells and sporeforming bacteria. A formulation of tea mixtures was then optimized by the desirability function aiming to maximize the inhibition of different strains and/or serotypes of Salmonella. The best tea formulation was chemically characterized by electrospray ionization mass spectrometry (ESI–MS). The linear effects of white and black teas were statistically significant (p < 0.05) as well as the interaction between green and white and green and black on the inhibition of S. Thyphimurium. Although the optimized tea mixture was effective against all Salmonella strains, the inhibition was substantially greater for specific serotypes, with differences observed even among strains of the same serotype (p < 0.05). A total of 11 phenolic constituents such as gallic acid, quinic acid, (+)-catechin/(−)-epicatechin, (−)-gallocatechin/(−)-epigalocatechin, coumaroylquinic acid, galloylquinic acid, and caffeoylquinic acid were tentatively identified using ESI–MS.
    Full-text · Article · Jan 2016
  • [Show abstract] [Hide abstract]
    ABSTRACT: This review is the first to summarize a decade of studies testing the use of easy ambient sonic-spray ionization mass spectrometry (EASI-MS) and its several sister techniques, Venturi (V-EASI), thermal imprinting (TI-EASI) and Spartan (S-EASI) mass spectrometry in food quality control and authentication. Since minimal or no sample preparation is required, such ambient desorption/ionization techniques have been shown to provide direct, fast and selective fingerprinting characterization at the molecular level based on the pools of the most typical components. They have also been found to be applicable on intact, undisturbed samples or on simple solvent extracts. Fundamentals of EASI-MS and its sister techniques, including mechanisms, devices, parameters and strategies, as well as the many applications reported for food analysis, are summarized and discussed.
    No preview · Article · Jan 2016 · The Analyst
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Ambient mass spectrometry has been demonstrated, via various proof-of-concept studies, to offer a powerful, rather universal, simple, fast, nondestructive, and robust tool in forensic chemistry, producing reliable evidence at the molecular level. Its nearly nondestructive nature also preserves the sample for further inquiries. This feature article demonstrates the applicability of ambient mass spectrometry in forensic chemistry and explains the challenges that need to be overcome for this technique to make the ultimate step from the academic world into forensic institutes worldwide. We anticipate that the many beneficial and matching figures of merit will bring forensic chemistry and ambient mass spectrometry to a long-term relationship, which is likely to get strongly consolidated over the years.
    Preview · Article · Jan 2016 · Analytical Chemistry
  • [Show abstract] [Hide abstract]
    ABSTRACT: The presence of fullerenes as natural constituents of carbonaceous materials or their formation as laser artifacts during laser desorption ionization (LDI) mass spectrometry (MS) analysis is reinvestigated and reviewed. The results using asphaltenes samples with varying composition as well as a standard polycyclic aromatic hydrocarbons (PAH) and fullerene samples as models have demonstrated that indeed Cn ring fullerenes are not natural constituents being formed as common and predominant artifacts upon laser radiation, and a series of incorrect assignments based on LDI-MS data of several carbonaceous materials, unfortunately, seems to have been made. When the present results are evaluated also in light of the vast literature on LDI-MS of carbonaceous materials, the formation of fullerene artifacts seems particular important for LDI-MS analysis of alphaltenes and other carbonaceous samples with considerably high levels of PAH and vary according to the type of laser used, and the intensity of the laser beam.
    No preview · Article · Jan 2016 · The Analyst
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Easy ambient sonic-spray ionization mass spectrometry (EASI-MS) is applied to the analysis of biodiesel blends prepared from soybean and animal fat biodiesel. A correlation was established between the ratio of abundance of linoleic acid (L) and oleic acid (O) methyl ester ions with the biodiesel blend composition. To compare these results from the EASI-MS technique, the L/O ratio of these blends was also determined using both gas chromatography with flame ionization detection (GC-FID) and gas chromatography with mass spectrometry (GC-MS). Both these classical techniques confirmed that the ratio between the mass fraction of FAME from L and O as measured by EASI-MS is indeed correlated with the blend composition of soybean-animal fat biodiesel.
    Full-text · Article · Jan 2016 · Analytical methods
  • Source

    Full-text · Article · Jan 2016 · Journal of the Brazilian Chemical Society
  • Source

    Full-text · Dataset · Dec 2015
  • Source
    Renan Galaverna · Nilton S Camilo · Marla N Godoi · Fernando Coelho · Marcos Nogueira Eberlin
    [Show abstract] [Hide abstract]
    ABSTRACT: Neutral and charge tagged reagents were used to investigate the mechanism of the classical Morita-Baylis-Hillman (MBH) reaction as well as its aza-version using mass spectrometry with electrospray ionization (ESI-MS). The use of an acrylate (activated alkene) with a methylimidazolium ion as charge tag eliminates the requirement for adding acids as ESI(+) additives, which are normally used to favor protonation and therefore detection of reaction partners (reagents, intermediates and products) by ESI(+)-MS. For both charge tagged reactions (MBH/aza-MBH), most reactants, intermediates and the final adducts were efficiently detected in the form of abundant doubly and singly charged ions. Characterization of the reactions partners was performed via both tandem mass spectrometry (ESI(+)-MS/MS) and accurate m/z measurements. The charge tagged reactions also showed faster conversion rates when compare to the neutral reaction, indicating a dualistic role for the charge tagged acrylate. It acts as both the reagent as well as a co-catalyst due to an inherent ionic-coordination nature of methylimidazolium ion, in which stabilizes the zwitterionic intermediates and reagents through different types of coordination ion pairs. Hemiacetal intermediates for the rate-limiting proton transfer step were also intercepted and characterized for both classical and aza-MBH charge tagged reactions.
    Full-text · Article · Dec 2015 · The Journal of Organic Chemistry
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Direct analysis of microbial cocultures grown on agar media by desorption electrospray ionization mass spectrometry (DESI-MS) is quite challenging. Due to the high gas pressure upon impact with the surface, the desorption mechanism does not allow direct imaging of soft or irregular surfaces. The divots in the agar, created by the high-pressure gas and spray, dramatically change the geometry of the system decreasing the intensity of the signal. In order to overcome this limitation, an imprinting step, in which the chemicals are initially transferred to flat hard surfaces, was coupled to DESI-MS and applied for the first time to fungal cocultures. Note that fungal cocultures are often disadvantageous in direct imaging mass spectrometry. Agar plates of fungi present a complex topography due to the simultaneous presence of dynamic mycelia and spores. One of the most devastating diseases of cocoa trees is caused by fungal phytopathogen Moniliophthora roreri. Strategies for pest management include the application of endophytic fungi, such as Trichoderma harzianum, that act as biocontrol agents by antagonizing M. roreri. However, the complex chemical communication underlying the basis for this phytopathogen-dependent biocontrol is still unknown. In this study, we investigated the metabolic exchange that takes place during the antagonistic interaction between M. roreri and T. harzianum. Using imprint-DESI-MS imaging we annotated the secondary metabolites released when T. harzianum and M. roreri were cultured in isolation and compared these to those produced after 3 weeks of coculture. We identified and localized four phytopathogen-dependent secondary metabolites, including T39 butenolide, harzianolide, and sorbicillinol. In order to verify the reliability of the imprint-DESI-MS imaging data and evaluate the capability of tape imprints to extract fungal metabolites while maintaining their localization, six representative plugs along the entire M. roreri/T. harzianum coculture plate were removed, weighed, extracted, and analyzed by liquid chromatography-high-resolution mass spectrometry (LC-HRMS). Our results not only provide a better understanding of M. roreri-dependent metabolic induction in T. harzianum, but may seed novel directions for the advancement of phytopathogen-dependent biocontrol, including the generation of optimized Trichoderma strains against M. roreri, new biopesticides, and biofertilizers.
    Full-text · Article · Dec 2015 · Analytical Chemistry
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This work aimed to evaluate the effect of hydrogen peroxide on the composition of sugarcane juice through mass spectrometry. The sugarcane juice was treated with different doses of hydrogen peroxide (1,000 and 50,000 ppm) and samples were collected during 2 h. The color reduction occurred only at a dose of 50,000 ppm and the peroxide promotes sedimentation of non-sugars in sugarcane juice under the conditions studied as there was increased relative abundance of sucrose within the ranges with increased reaction time.Practical ApplicationsIn this paper, we studied the mechanism of color reduction of sugarcane juice as a new innovative technology to crystal sugar production as a substitute for sulfur use, which was related to health problems.
    Full-text · Article · Dec 2015 · Journal of Food Processing and Preservation
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This study proposes a new and fast protocol using ultra-high resolution (Rp of 100,000) and accuracy (≤1 ppm) mass spectrometry in a "zig-zag" time-of-flight analyzer with electrospray ionization in the negative ion mode (ESI(-)-UHR TOF-MS) for direct screening of free fatty acids (FA) in sediments. As a proof-of-concept study, the profiles of FA in surface sediments from contrasting environments, including estuarine, coastal, and polar samples, and a sedimentary core were assessed. The profiles of saturated FA from C12-C36 revealed a strong even-over-odd preference with specific distributions for each selected environment. The terrigenous/aquatic ratio (TAR) and average chain length (ACL) proxies were calculated based on results obtained by ESI(-)-UHR TOF-MS and GC-MS for all the samples to validate the proposed protocol. Applying the paired t-test at a confidence level of 95%, we found a t-statistic equal to 2.05 for TAR and 2.01 for ACL, which are lower than the critical value of t. Thus, there is no significant difference between the results obtained by the two techniques at a confidence level of 95%. In addition, ESI(-)-UHR TOF-MS exhibited lower limits of quantification for free FA (10ng/ml) compared to those obtained by GC-MS for fatty acid methyl esters (FAME) (50ng/ml). Direct ESI(-)-UHR TOF-MS offers therefore a reliable, fast, and relatively simple MS protocol to obtain free FA profiles from sediments. The results strongly suggest that the method presented herein has future geochemical applications in the rapid screening of FA biomarkers in sediment samples, reducing both sample preparation as well as analysis time.
    Full-text · Article · Dec 2015 · Organic Geochemistry
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background: Chromobacterium violaceum (C. violaceum) occurs abundantly in a variety of ecosystems, including ecosystems that place the bacterium under stress. This study assessed the adaptability of C. violaceum by submitting it to nutritional and pH stresses and then analyzing protein expression using bi-dimensional electrophoresis (2-DE) and Maldi mass spectrometry. Results: Chromobacterium violaceum grew best in pH neutral, nutrient-rich medium (reference conditions); however, the total protein mass recovered from stressed bacteria cultures was always higher than the total protein mass recovered from our reference culture. The diversity of proteins expressed (repressed by the number of identifiable 2-DE spots) was seen to be highest in the reference cultures, suggesting that stress reduces the overall range of proteins expressed by C. violaceum. Database comparisons allowed 43 of the 55 spots subjected to Maldi mass spectrometry to be characterized as containing a single identifiable protein. Stress-related expression changes were noted for C. violaceum proteins related to the previously characterized bacterial proteins: DnaK, GroEL-2, Rhs, EF-Tu, EF-P; MCP, homogentisate 1,2-dioxygenase, Arginine deiminase and the ATP synthase β-subunit protein as well as for the ribosomal protein subunits L1, L3, L5 and L6. The ability of C. violaceum to adapt its cellular mechanics to sub-optimal growth and protein production conditions was well illustrated by its regulation of ribosomal protein subunits. With the exception of the ribosomal subunit L3, which plays a role in protein folding and maybe therefore be more useful in stressful conditions, all the other ribosomal subunit proteins were seen to have reduced expression in stressed cultures. Curiously, C. violeaceum cultures were also observed to lose their violet color under stress, which suggests that the violacein pigment biosynthetic pathway is affected by stress. Conclusions: Analysis of the proteomic signatures of stressed C. violaceum indicates that nutrient-starvation and pH stress can cause changes in the expression of the C. violaceum receptors, transporters, and proteins involved with biosynthetic pathways, molecule recycling, energy production. Our findings complement the recent publication of the C. violeaceum genome sequence and could help with the future commercial exploitation of C. violeaceum.
    Full-text · Article · Dec 2015 · BMC Microbiology
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Flaxseed (Linum usitatissimum L.) oil was obtained via subcritical n-propane fluid extraction (SubFE) under different temperatures and pressures with an average yield of 28% and its composition, purity and oxidative stability were compared to oils obtained via conventional solvent extraction methods (SEMs). When the oxidative stability was measured by differential scanning calorimetry, the oil was found to be up to 5 times more resistant to lipid oxidation as compared to the SEM oils. Direct infusion electrospray ionization mass spectrometry (ESI-MS) analysis showed characteristic and similar TAG profiles for SubFE and SEMs oils but higher purity for the SubFE oil. The flaxseed oil content of β-tocopherol, campesterol, stigmasterol and sitosterol were quantified via GC-MS. SubFE showed to be a promising alternative to conventional SEM since SubFE provides an oil with higher purity and higher oxidation stability and with comparable levels of biologically active components. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Full-text · Article · Dec 2015 · Food Chemistry
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: RationaleBrazil is the largest producer of sugar cane bioethanol in the world. Isotope ratio mass spectrometry (IRMS) is the technique of choice to certify the origin/raw materials for ethanol production, but the lack of certified reference materials (CRMs) for accurate measurements of δ13C values traceable to Vienna Pee Dee Belemnite (VPDB), the international zero point for 13C/12C measurements, certified and compatible with gas chromatography (GC)/IRMS instruments may compromise the accuracy of δ13C determinations.Methods We evaluated the influence of methods for the calibration and normalization of raw δ13C values of ethanol samples. Samples were analyzed by GC/C/IRMS using two different GC columns. Different substances were used as isotopic standards for the working gas calibration. The δ13C values obtained with the three methods of normalization were statistically compared with those obtained with elemental analyzer (EA)/IRMS, since the δ13C results obtained using EA are traceable to VPDB via the NBS 22 reference material.ResultsIt was observed that both the isotopic reference material for CO2 calibration and the GC column have a major effect on the δ13C measurements, leading to a bias of almost 2–3 ‰ in the δ13C values. All three methods of normalization were equivalent in performance, enabling an improvement in the GC/C/IRMS accuracy, compared with the EA/IRMS reference values for the samples.Conclusions All the methods of CO2 calibration, chromatography and normalization presented in this work demonstrated several sources of traceability and accuracy loss for the determination of δ13C values in ethanol fuel samples by GC/C/IRMS. This work has also shown the importance of using proper CRMs traceable to VPBD that should be compatible and certified using GC/C/IRMS, ideally in a wide range of δ13C values. This is important not only for bioethanol fuel samples, but also for many analytes commonly analyzed by IRMS. Copyright © 2015 John Wiley & Sons, Ltd.
    Full-text · Article · Nov 2015 · Rapid Communications in Mass Spectrometry
  • Source

    Full-text · Conference Paper · Nov 2015
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Understanding the molecular basis of schizophrenia is essential for disease management, and several molecular biology tools have been employed for this purpose. Mass spectrometry, which is used mostly in proteomic and metabolomic studies, is one such tool. Here, we present the first psychiatric study to use mass spectrometry imaging (MSI) with desorption electrospray ionization (DESI). Preparation of samples for use with DESI-MSI is remarkably simple and quick and preserves the spatial distribution of analytes. By using this tool, we found differences in the phospholipid content in schizophrenia postmortem brains. These results validate both the role of phospholipids in schizophrenia and the value of this MS tool in furthering the understanding of the molecular aspects of the disease.
    Full-text · Article · Nov 2015 · Schizophrenia Research
  • Source

    Full-text · Conference Paper · Oct 2015
  • [Show abstract] [Hide abstract]
    ABSTRACT: Purpose: The aim of the present study was to analyze the lipid profile of follicular fluid from patients with endometriosis and endometrioma who underwent in vitro fertilization treatment (IVF). Methods: The control group (n = 10) was composed of women with tubal factor or minimal male factor infertility who had positive pregnancy outcomes after IVF. The endometriosis group consisted of women with endometriosis diagnosed by videolaparoscopy (n = 10), and from the same patients, the endometriomas fluids were collected, which composed the endometrioma group (n = 10). From the follicular fluid and endometriomas, lipids were extracted by the Bligh and Dyer method, and the samples were analyzed by tandem mass spectrometry. Results: We observed phosphatidylglycerol phosphate, phosphatidylcholine, phosphatidylserine, and phosphatidylnositol bisphosphate in the control group. In the endometriosis group, sphingolipids and phosphatidylcholines were more abundant, while in the endometrioma group, sphingolipids and phosphatidylcholines with different m/z from the endometriosis group were found in high abundance. Conclusion: This analysis demonstrated that there is a differential representation of these lipids according to their respective groups. In addition, the lipids found are involved in important mechanisms related to endometriosis progress in the ovary. Thus, the metabolomic approach for the study of lipids may be helpful in potential biomarker discovery.
    No preview · Article · Oct 2015 · Journal of Assisted Reproduction and Genetics

Publication Stats

12k Citations
2,006.07 Total Impact Points


  • 2015
    • National Institute of Metrology, Quality and Technology (Inmetro)
      • Division of Chemical Metrology
      Rio de Janeiro, Rio de Janeiro, Brazil
  • 1988-2015
    • University of Campinas
      • Institute of Chemistry
      Conceição de Campinas, São Paulo, Brazil
  • 2014
    • Federal University of Juiz de Fora
      Juiz de Fora, Minas Gerais, Brazil
  • 2004-2014
    • University of São Paulo
      • • Faculdade de Ciências Farmacêuticas (FCF)
      • • Instituto de Química (IQ) (São Paulo)
      San Paulo, São Paulo, Brazil
    • São Paulo State University
      • Instituto de Química - Araraquara
      São Paulo, Estado de Sao Paulo, Brazil
    • University of California, Santa Barbara
      • Department of Chemistry and Biochemistry
      Santa Barbara, California, United States
  • 2010
    • Universidade Federal de São Paulo
      San Paulo, São Paulo, Brazil
    • Federal University of Santa Catarina
      Nossa Senhora do Destêrro, Santa Catarina, Brazil
    • Federal University of Rio de Janeiro
      Rio de Janeiro, Rio de Janeiro, Brazil
  • 2009
    • Indian Institute of Chemical Technology
      • Molecular Modelling Group (IICT)
      Bhaganagar, Andhra Pradesh, India
  • 2007
    • Universidad de Talca
      Talca, Maule, Chile
  • 1998-2007
    • Federal University of Minas Gerais
      • Departamento de Química
      Belo Horizonte, Estado de Minas Gerais, Brazil
  • 2006
    • Universidade Bandeirante de São Paulo (UNIBAN)
      San Paulo, São Paulo, Brazil
  • 1991-2006
    • Purdue University
      • Department of Chemistry
      West Lafayette, Indiana, United States
  • 2005
    • Federal Rural University of Rio de Janeiro
      সেরওপেডিকা, Rio de Janeiro, Brazil
  • 2002
    • University of Helsinki
      • Division of Pharmaceutical Chemistry
      Helsinki, Uusimaa, Finland
  • 2001
    • University of Naples Federico II
      Napoli, Campania, Italy
    • Federal University of Pernambuco
      • Departamento de Química Fundamental
      Arrecife, Pernambuco, Brazil