Analysis of total glucosinolates and chromatographically purified benzylglucosinolate in organic and conventional vegetables

The limited availability of foods that are free of pesticides has led Brazil to search for alternative production methods to meet the desires of consumers. Currently, organic cultivation represents a production system that complies with general expectations of producers and consumers. Organic cultivation is particularly interesting mainly because of its effect on plant secondary metabolite content, which may help plants to naturally combat pests; in humans, these substances can also contribute to the prevention of chronic diseases. We report on the extraction of glucosinolates (both as total glucosinolates and as benzylglucosinolate) with trifluoroacetic acid addition in a 70:30 MeOH:water (v/v). Total glucosinolates, determined by a thioglucosidase coupled assay, were measured in different Brassicaceae species and were similar to values reported in the literature. For broccoli, analyses were carried out separately on inflorescences, leaves and stalks; analyses were also conducted on thermally processed samples to simulate cooking. Furthermore, when the analysis was conducted on conventional and organic products, the highest concentrations of these substances were most often found in organically cultivated Brassicaceae. The benzylglucosinolate concentrations were evaluated on the same samples using HPLC. The concentration of benzylglucosinolate was significantly higher in organically cultivated vegetables, as well. © 2012 Elsevier Ltd.

Electrochemical Determination of Organic Compounds in Automotive Fuels

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Characterization and thermal study of organic extracts of urban solid waste

The urban residues put in landfill of the city of Sa˜o Carlos-SP, Brazil, in 2004 represent 58.7 % of decomposed organic material. The aim of this research was to characterize samples of urban solid waste and its organic extracts targeting the use of this residue without damaging the environment. The curves were obtained in a nitrogen atmosphere, a heating rate of 20 C min-1 , the temperature of 30–600 C. In the original sample after humidity loss, an event occured concerning the water constitution in the TG curve with an endothermic peak in the DTA curve. There was a presence of inorganic residue in the ashes. The organic matter present in the USR sample disposed in the landfill is constituted by several polarity, organics compounds from the degradation of lignin, cellulose, lipids, and other materials which thermal stabilities are distinct. The hexane extract features in its constitution two fatty acids, stearic and triacontano´ic, which are nonpolar compounds originating from bacteria present in the residue. The acids groups in extract hexane also were evidenced by X-ray diffraction and FTIR.

Continuous enzymatic interesterification of milkfat with soybean oil produces a highly spreadable product rich in polyunsaturated fatty acids

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cooperative effects of H+ and H- hydrido carbonyl ruthenium derivatives; role of homogeneous and heterogeneous protonic and lewis acids in catalytic hydrocarbonylation reactions

The role played by H+ hydrido iodocarbonyl and H- hydrido carbonyl ruthenium catalysts in the different catalytic steps of hydroformylation and hydroesterification of olefins, and in the homologation of alcohols has been investigated. The H- hydrido carbonyl species are mainly involved in the activation of olefins and in the hydrogenation of the acyl intermediates to aldehydes and alcohols, whereas the H+ hydrido iodocarbonyl derivatives are involved in the activation of alcohols and other oxygenated substrates, and in their carbonylation to esters. The cooperation between the two species, possible under particular reaction conditions, results in an improvement of the selectivity towards homologation (carbonylation plus hydrogenation) products. Heterogeneous Lewis acid promoters, easily recyclable from the reaction mixture, have also been successfully used in the hydrocarbonylation of alcohols, resulting in an increase of the carbonylation and homologation products. A reaction pathway in agreement with the experimental results is discussed. © 1989.

Fatty acid profile, trans-octadecenoic, alpha-linolenic and conjugated linoleic acid contents differing in certified organic and conventional probiotic fermented milks

Development of dairy organic probiotic fermented products is of great interest as they associate ecological practices and benefits of probiotic bacteria. As organic management practices of cow milk production allow modification of the fatty acid composition of milk (as compared to conventional milk), we studied the influence of the type of milk on some characteristics of fermented milks, such as acidification kinetics. bacterial counts and fatty acid content. Conventional and organic probiotic fermented milks were produced using Bifidobacterium animalis subsp. lactis HN019 in co-culture with Streptococcus thermophilus TA040 and Lactobacillus delbrueckii subsp. bulgaricus LB340. The use of organic milk led to a higher acidification rate and cultivability of Lactobacillus bulgaricus. Fatty acids profile of organic fermented milks showed higher amounts of trans-octadecenoic acid (C18:1, 1.6 times) and polyunsaturated fatty acids, including cis-9 trans-11. C18:2 conjugated linoleic (CLA-1.4 times), and alpha-linolenic acids (ALA-1.6 times), as compared to conventional fermented milks. These higher levels were the result of both initial percentage in the milk and increase during acidification, with no further modification during storage. Finally, use of bifidobacteria slightly increased CLA relative content in the conventional fermented milks, after 7 days of storage at 4 degrees C, whereas no difference was seen in organic fermented milks. (C) 2012 Elsevier Ltd. All rights reserved.

New routes to enantioenriched substances through small organic molecules

In this thesis we will disclose the results obtained from the diastereoisomeric salt formation (n salt, p salt and p1,n1 salt) between non-racemic trans-chrysanthemic acid (trans-ChA) and pure enantiomers of threo-2-dimethylamino-1-phenyl-1,3-propanediol (DMPP). The occurrence of p1,n1 salt formation can have profound effects on enantiomer separation of scalemic (non-racemic) mixtures. This phenomenon when accompanied by substrate self-association impedes the complete recovery of the major enantiomer through formation of an inescapable racemate cage. A synthetic sequence for the asymmetric synthesis of bicyclo[3.2.0]heptanones and bicyclo[3.2.0]hept-3-en-6-ones through a cycloaddition strategy is reported. The fundamental step is a [2+2]-cycloaddition of an enantiopure amide derived from the reaction between a set of acids and an oxazolidinone as the chiral auxiliary. The inter- and intramolecular cycloaddition of in situ-generated keteniminium salts gives bicycles with a good enantioselection. A key intermediate of Iloprost, a chemically stable and biologically active mimic of prostacyclin PGI2 is synthesized following a ‘green approach’. An example of simple optical resolution of this racemic intermediate involving the diastereoisomeric salt formation is described.

DNA hybrid materials consisting of oligonucleotides and organic molecules: synthesis, characterization and applications

The goal of this thesis was to increase the functionality of pristine DNA scaffolds by functionalizing them with fluorescent dyes and hydrophobic moieties. Two important steps were necessary to realize this aim successfully. First, nucleic acids needed to be synthesized making use of multidisciplinary toolbox for the generation and manipulation of polynucleic acids. The most important techniques were the solid phase synthesis involving the incorporation of standard and modified phosphoramidite building blocks as well as molecular biology procedures like the polymerase chain reaction, the bacterial amplification of plasmids and the enzymatic digestion of circular vectors. Second, and evenly important, was the characterization of the novel bioorganic hybrid structures by a multitude of techniques, especially optical measurements. For studying DNA-dye conjugates methods like UV/Vis and photoluminescence spectroscopy as well as time resolved luminescence spectroscopy were utilized. While these measurements characterized the bulk behavior of an ensemble of DNA-dye hybrids it was necessary for a complete understanding of the systems to look at single structures. This was done by single-molecule fluorescence spectroscopy and fluorescence correlation spectroscopy. For complete analysis the optical experiments were complemented by direct visualization techniques, i.e. high resolution transmission electron microscopy and scanning force microscopy.

Study of the genes involved in Naphthenic acids (NAs) degradation by Rhodococcus spp.

Naphthenic acids (NAs) are an important group of organic pollutants mainly found in hydrocarbon deposits. Although these compounds are toxic, recalcitrant, and persistent in the environment, we are just learning the diversity of microbial communities involved in NAs- degradation and the mechanisms by which NAs are biodegraded. Studies have shown that naphthenic acids are susceptible to biodegradation, which decreases their concentration and reduces toxicity. Nevertheless, little is still known about their biodegradability. The present PhD Thesis’s work is aimed to study the biodegradation of simple model NAs using bacteria strains belonging to the Rhodococcus genus. In particular, Rh. sp. BCP1 and Rh. opacus R7 were able to utilize NAs such as cyclohexane carboxylic acid and cyclopentane carboxylic acid as the sole carbon and energy sources, even at concentrations up to 1000 mg/L. The presence of either substituents or longer carboxylic acid chains attached to the cyclohexane ring negatively affected the growth by pure bacterial cultures. Moreover, BCP1 and R7 cells incubated in the presence of CHCA or CPCA show a general increase of saturated and methyl-substituted fatty acids in their membrane, while the cis-mono-unsaturated ones decrease, as compared to glucose-grown cells. The observed lipid molecules modification during the growth in the presence of NAs is suggested as a possible mechanism to decrease the fluidity of the cell membrane to counteract NAs toxicity. In order to further evaluate this toxic effect on cell features, the morphological changes of BCP1 and R7 cells were also assessed through Transmission Electron Microscopy (TEM), revealing interesting ultrastructural changes. The induction of putative genes, and the construction of a random transposon mutagenesis library were also carried out to reveal the mechanisms by which these Rhodococcus strains can degrade toxic compounds such as NAs.

Development and application of mass-spectrometric methods for the quantification and characterization of organic compounds in ice cores

Eisbohrkerne stellen wertvolle Klimaarchive dar, da sie atmosphärisches Aerosol konservieren. Die Analyse chemischer Verbindungen als Bestandteil atmosphärischer Aerosole in Eisbohrkernen liefert wichtige Informationen über Umweltbedingungen und Klima der Vergangenheit. Zur Untersuchung der α-Dicarbonyle Glyoxal und Methylglyoxal in Eis- und Schneeproben wurde eine neue, sensitive Methode entwickelt, die die Stir Bar Sorptive Extraction (SBSE) mit der Hochleistungsflüssigchromatographie-Massenspektrometrie (HPLC-MS) kombiniert. Zur Analyse von Dicarbonsäuren in Eisbohrkernen wurde eine weitere Methode entwickelt, bei der die Festphasenextraktion mit starkem Anionenaustauscher zum Einsatz kommt. Die Methode erlaubt die Quantifizierung aliphatischer Dicarbonsäuren (≥ C6), einschließlich Pinsäure, sowie aromatischer Carbonsäuren (wie Phthalsäure und Vanillinsäure), wodurch die Bestimmung wichtiger Markerverbindungen für biogene und anthropogene Quellen ermöglicht wurde. Mit Hilfe der entwickelten Methoden wurde ein Eisbohrkern aus den Schweizer Alpen analysiert. Die ermittelten Konzentrationsverläufe der Analyten umfassen die Zeitspanne von 1942 bis 1993. Mittels einer Korrelations- und Hauptkomponentenanalyse konnte gezeigt werden, dass die organischen Verbindungen im Eis hauptsächlich durch Waldbrände und durch vom Menschen verursachte Schadstoffemissionen beeinflusst werden. Im Gegensatz dazu sind die Konzentrationsverläufe einiger Analyten auf den Mineralstaubtransport auf den Gletscher zurückzuführen. Zusätzlich wurde ein Screening der Eisbohrkernproben mittels ultrahochauflösender Massenspektrometrie durchgeführt. Zum ersten Mal wurden in diesem Rahmen auch Organosulfate und Nitrooxyorganosulfate in einem Eisbohrkern identifiziert.

Development, characterization, and application of flowing atmospheric-pressure afterglow ionization for mass spectrometric analysis of ambient organic aerosols

Addressing current limitations of state-of-the-art instrumentation in aerosol research, the aim of this work was to explore and assess the applicability of a novel soft ionization technique, namely flowing atmospheric-pressure afterglow (FAPA), for the mass spectrometric analysis of airborne particulate organic matter. Among other soft ionization methods, the FAPA ionization technique was developed in the last decade during the advent of ambient desorption/ionization mass spectrometry (ADI–MS). Based on a helium glow discharge plasma at atmospheric-pressure, excited helium species and primary reagent ions are generated which exit the discharge region through a capillary electrode, forming the so-called afterglow region where desorption and ionization of the analytes occurs. Commonly, fragmentation of the analytes during ionization is reported to occur only to a minimum extent, predominantly resulting in the formation of quasimolecular ions, i.e. [M+H]+ and [M–H]– in the positive and the negative ion mode, respectively. Thus, identification and detection of signals and their corresponding compounds is facilitated in the acquired mass spectra. The focus of the first part of this study lies on the application, characterization and assessment of FAPA–MS in the offline mode, i.e. desorption and ionization of the analytes from surfaces. Experiments in both positive and negative ion mode revealed ionization patterns for a variety of compound classes comprising alkanes, alcohols, aldehydes, ketones, carboxylic acids, organic peroxides, and alkaloids. Besides the always emphasized detection of quasimolecular ions, a broad range of signals for adducts and losses was found. Additionally, the capabilities and limitations of the technique were studied in three proof-of-principle applications. In general, the method showed to be best suited for polar analytes with high volatilities and low molecular weights, ideally containing nitrogen- and/or oxygen functionalities. However, for compounds with low vapor pressures, containing long carbon chains and/or high molecular weights, desorption and ionization is in direct competition with oxidation of the analytes, leading to the formation of adducts and oxidation products which impede a clear signal assignment in the acquired mass spectra. Nonetheless, FAPA–MS showed to be capable of detecting and identifying common limonene oxidation products in secondary OA (SOA) particles on a filter sample and, thus, is considered a suitable method for offline analysis of OA particles. In the second as well as the subsequent parts, FAPA–MS was applied online, i.e. for real time analysis of OA particles suspended in air. Therefore, the acronym AeroFAPA–MS (i.e. Aerosol FAPA–MS) was chosen to refer to this method. After optimization and characterization, the method was used to measure a range of model compounds and to evaluate typical ionization patterns in the positive and the negative ion mode. In addition, results from laboratory studies as well as from a field campaign in Central Europe (F–BEACh 2014) are presented and discussed. During the F–BEACh campaign AeroFAPA–MS was used in combination with complementary MS techniques, giving a comprehensive characterization of the sampled OA particles. For example, several common SOA marker compounds were identified in real time by MSn experiments, indicating that photochemically aged SOA particles were present during the campaign period. Moreover, AeroFAPA–MS was capable of detecting highly oxidized sulfur-containing compounds in the particle phase, presenting the first real-time measurements of this compound class. Further comparisons with data from other aerosol and gas-phase measurements suggest that both particulate sulfate as well as highly oxidized peroxyradicals in the gas phase might play a role during formation of these species. Besides applying AeroFAPA–MS for the analysis of aerosol particles, desorption processes of particles in the afterglow region were investigated in order to gain a more detailed understanding of the method. While during the previous measurements aerosol particles were pre-evaporated prior to AeroFAPA–MS analysis, in this part no external heat source was applied. Particle size distribution measurements before and after the AeroFAPA source revealed that only an interfacial layer of OA particles is desorbed and, thus, chemically characterized. For particles with initial diameters of 112 nm, desorption radii of 2.5–36.6 nm were found at discharge currents of 15–55 mA from these measurements. In addition, the method was applied for the analysis of laboratory-generated core-shell particles in a proof-of-principle study. As expected, predominantly compounds residing in the shell of the particles were desorbed and ionized with increasing probing depths, suggesting that AeroFAPA–MS might represent a promising technique for depth profiling of OA particles in future studies.

Accurate relative pKa calculations for carboxylic acids using complete basis set and Gaussian-n models combined with continuum solvation methods

The complete basis set methods CBS-4, CBS-QB3, and CBS-APNO, and the Gaussian methods G2 and G3 were used to calculate the gas phase energy differences between six different carboxylic acids and their respective anions. Two different continuum methods, SM5.42R and CPCM, were used to calculate the free energy differences of solvation for the acids and their anions. Relative pKa values were calculated for each acid using one of the acids as a reference point. The CBS-QB3 and CBS-APNO gas phase calculations, combined with the CPCM/HF/6-31+G(d)//HF/6-31G(d) or CPCM/HF/6-31+G(d)//HF/6-31+G(d) continuum solvation calculations on the lowest energy gas phase conformer, and with the conformationally averaged values, give results accurate to ½ pKa unit. © 2001 American Institute of Physics.

Acoustic Detection of Organic Enrichment in Sediments at a Salmon Farm Is Confirmed by Independent Groundtruthing Methods

Acoustic backscatter contrast in depositional sediments under salmon farm cages in the Bay of Fundy, Canada, was correlated with localized changes in (unknown) sediment geotechnical properties, as indicated by 4 independent measures of organic enrichment. Sediment total sulfides and redox potentials, enzyme hydrolyzable amino acids, sediment profile imaging and macrofaunal samples, taken at mid-cage positions, each rejected the null hypothesis that salmon cage footprints, defined acoustically as high backscatter areas, were indistinguishable from nearby reference areas. Acoustic backscatter imaging appears capable of mapping organic enrichment in depositional sediments caused by excessive inputs of salmon farm wastes associated with intensive aquaculture.