scholarly journals Chemical characterization of agroforestry solid residues aiming its utilization as adsorbents for metals in water

2015 ◽  
Vol 19 (1) ◽  
pp. 77-83 ◽  
Author(s):  
Francisco H. M. Luzardo ◽  
Fermin G. Velasco ◽  
Clemildes P. Alves ◽  
Ivea K. da S. Correia ◽  
Lázaro L. Cazorla
Keyword(s):  
Adsorption Capacity ◽  
Functional Groups ◽  
Chemical Structure ◽  
Chemical Characterization ◽  
Soluble Solids ◽  
Carbonyl Groups ◽  
Specific Chemical ◽  
Coconut Shells ◽  
Potential Use

In this work, a study of the correlation between the functional groups present in the chemical structure of the fibers of coconut shells, cocoa and eucalyptus, and their adsorption capacity of Cd+2 and Cu+2 ions from water was performed. The content of soluble solids and reactive phenols in aqueous extracts were determined. The chemical functional groups present in the fibers were examined using the IR spectra. The adsorption capacity of the peels was determined using atomic absorption spectrophotometer. For Cd+2, a significant correlation between the adsorption capacity and some specific chemical functional groups present in the fiber was verified. The potential use of these peels, as adsorbent of Cd+2 ions, is based on the presence of OH functional groups such as aryl-OH, aryl-O-CH2 of phenol carboxylic acids, as well as carbonyl groups derived from carboxylic acid salts, in these fibers.

scholarly journals Chemical Evaluation of Eumelanin Maturation by ToF-SIMS and Alkaline Peroxide Oxidation HPLC Analysis

2020 ◽  
Vol 22 (1) ◽  
pp. 161
Author(s):  
Martin Jarenmark ◽  
Peter Sjövall ◽  
Shosuke Ito ◽  
Kazumasa Wakamatsu ◽  
Johan Lindgren
Keyword(s):  
Molecular Structure ◽  
Secondary Ion Mass Spectrometry ◽  
Chemical Characterization ◽  
Experimental Treatment ◽  
Negative Ion ◽  
Pressure Treatment ◽  
Peroxide Oxidation ◽  
Specific Chemical ◽  
Tof Sims

Residual melanins have been detected in multimillion-year-old animal body fossils; however, confident identification and characterization of these natural pigments remain challenging due to loss of chemical signatures during diagenesis. Here, we simulate this post-burial process through artificial maturation experiments using three synthetic and one natural eumelanin exposed to mild (100 °C/100 bar) and harsh (250 °C/200 bar) environmental conditions, followed by chemical analysis employing alkaline hydrogen peroxide oxidation (AHPO) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Our results show that AHPO is sensitive to changes in the melanin molecular structure already during mild heat and pressure treatment (resulting, e.g., in increased C-C cross-linking), whereas harsh maturation leads to extensive loss of eumelanin-specific chemical markers. In contrast, negative-ion ToF-SIMS spectra are considerably less affected by mild maturation conditions, and eumelanin-specific features remain even after harsh treatment. Detailed analysis of ToF-SIMS spectra acquired prior to experimental treatment revealed significant differences between the investigated eumelanins. However, systematic spectral changes upon maturation reduced these dissimilarities, indicating that intense heat and pressure treatment leads to the formation of a common, partially degraded, eumelanin molecular structure. Our findings elucidate the complementary nature of AHPO and ToF-SIMS during chemical characterization of eumelanin traces in fossilized organismal remains.

scholarly journals EVALUATION OF ALKALINE PRETREATMENT ON THE ENZYMATIC HYDROLYSIS OF CARNAUBA STRAW RESIDUE

2019 ◽  
Vol 8 (3) ◽  
Author(s):  
Alan De Oliveira Campos ◽  
Francinaldo Leite Da Silva ◽  
Emilianny Rafaely Batista Magalhães ◽  
Gorete Ribeiro De Macedo ◽  
Everaldo Silvino Dos Santos
Keyword(s):  
Enzymatic Hydrolysis ◽  
Cellulosic Ethanol ◽  
Chemical Characterization ◽  
Crystallinity Index ◽  
Biomass Pretreatment ◽  
Cellulose Conversion ◽  
Hydrolysis Of ◽  
Potential Use ◽  
Second Generation Ethanol

Carnauba (Copernicia prunifera) straw residue generated from production of its wax is rich in cellulose, thus showing a potential use in the production of second generation ethanol. However, the high lignin and hemicellulose load associated with cellulose makes it difficult the enzymatic attack, thus having the need of an adequate pretreatment of this material. The objective of this study was to optimize the enzymatic hydrolysis of carnauba straw residue, focusing on the alkaline biomass pretreatment. Therefore, NaOH solutions at concentrations of 1.0% (w/v) (PA1), 2.0% (w/v) (PA2), 3.0% (w/v) (PA3) and 4.0% (w/v) (PA4) were used. The chemical and physical characterization of natural and pre-treated carnauba straw were according to the NREL, and DRX and FTIR performed analyzes. The materials chemical characterization showed that all the used pretreatments were able to remove a significant amount of lignin and hemicellulose, which can improve the enzymes access, favoring the increase of cellulose conversion. In relation to DRX analysis an increase in crystallinity index happens reaching up to 55.15% after the pretreatment PA4, which may be associated to the removal of hemicellulose and amorphous lignin, related to cellulose. After a period of 96 hours of enzymatic hydrolysis, the PA4 pretreated residue showed the best performance with a cellulosic conversion of 78%. Spite of a slightly lower performance of the residue that presented higher cellulose conversion, the pretreated material PA2 is an alternative to reduce costs in the cellulosic ethanol production.

Quantum chemical shape: new density domain relations for the topology of molecular bodies, functional groups, and chemical bonding

1994 ◽  
Vol 72 (3) ◽  
pp. 928-935 ◽  
Author(s):  
Paul G. Mezey
Keyword(s):  
Functional Groups ◽  
Chemical Bonding ◽  
Quantum Chemical ◽  
Chemical Characterization ◽  
Finite Sequence ◽  
Molecular Shape ◽  
Wide Range ◽  
Density Values ◽  
Skeletal Model

A density domain (DD) is the formal body enclosed by a molecular isodensity contour (MIDCO) surface. Individual nuclear neighborhoods and various formal molecular fragments can be regarded as fuzzy moieties of electron densities, dominated by one or several nuclei. Such a fuzzy fragment involves a whole range of density values, hence it cannot be described by a single MIDCO, but it can be represented by a sequence of density domains. Within the chemically important range of density values, there are only a finite number of topologically different bodies of density domains. In the Density Domain Approach, chemical bonding is described by the interfacing and mutual interpenetration of local fuzzy charge density clouds. The bonding between fragments of a molecule is characterized by a finite sequence of density domains within a wide range of density values and by the correponding sequence of topological patterns of the mutual interpenetration of these fragments. In earlier works, the DD approach was advocated as an alternative to the conventional "skeletal model" of chemical bonding. The classically motivated line diagrams as representatives of bonding are replaced by the pattern of interpenetration of fuzzy fragment bodies at various density thresholds. In this study, novel DD relations are described, suitable for a quantum chemical characterization of functional groups, the local shape properties of such groups, and their contributions to global molecular shape.

scholarly journals Biometric and Chemical Characterization of Fruits From Selections of Platonia insignis Mart., Native of the State of Maranhão, Brazil

2019 ◽  
Vol 11 (2) ◽  
pp. 376
Author(s):  
R. F. Santos ◽  
J. R. G. Araujo ◽  
A. C. V. Neves Junior ◽  
P. A. F. R. Melo ◽  
L. P. V. Silva ◽  
...  
Keyword(s):  
Chemical Characterization ◽  
Soluble Solids ◽  
Pulp Yield ◽  
Transverse Diameter ◽  
Fruit Species ◽  
Coefficients Of Variation ◽  
Significant Difference ◽  
Nutritional Characteristics ◽  
Superior Genotypes

Brazil has a range of fruit species, especially native ones, which play an important role in the life of local populations, but are still little studied, as is the case of bacuri (Platonia insignis Mart.). P. insignis is a fruit tree species native from Amazon region and has great economic potential, mainly due to its excellent organoleptic and nutritional characteristics. Therefore, there is a need for research that seeks the proper use of the species, as well as the selection of superior genotypes. Thus, the objective of this study was to characterize biometric and chemically fruits of eight selections of native P. insignis plants, from the municipalities of Presidente Juscelino and Santa Rita both located in Lower Munim region, state of Maranhão, Brazil. For the biometric characterization, 20 fruits, individually, were analyzed as to mass, longitudinal diameter, transverse diameter, conformation index, seed number, parthenocarpic segments number, pulp yield and bark mass, and for the chemical characterization, samples composed of six fruits were analyzed as to soluble solids (°Brix), total acidity (% citric acid), soluble solids/acidity ratio and pH. There was significant difference for all characteristics evaluated. High coefficients of variation were observed, indicating variability among the selections and possibility of taking advantage for the genetic improvement. The results allow to indicate the fruits analyzed, both for the industrial market and for the in natura consumption, especially for the ‘Domingão’ and ‘Mamão’ selections.

scholarly journals Physical and chemical characterization of yacon tuberous roots at different altitudes and planting times

2018 ◽  
Vol 36 (2) ◽  
pp. 199-204 ◽  
Author(s):  
Diego MN Silva ◽  
Raquel R Lima ◽  
Fábio L Oliveira ◽  
Luciano JQ Teixeira ◽  
Leonard CA Machado
Keyword(s):  
Reducing Sugars ◽  
Chemical Characterization ◽  
Soluble Solids ◽  
Tuberous Roots ◽  
Compression Cycle ◽  
Solids Content ◽  
Physical And Chemical ◽  
Different Altitudes

ABSTRACT The post-harvest quality of yacon tuberous roots produced at different altitudes and planting times were characterized in this study. The experiment was conducted in the South of Espírito Santo State in two locations, one at 837 m altitude and the other one at 113 m altitude. The experimental design, in each place, was randomized blocks with four replications, and the treatments consisted of three planting seasons: April (autumn), July (winter) and September (spring). After harvest of the tuberous roots, we evaluated pH, titratable total acidity, moisture content, soluble solids, reducing sugars, crude fiber and ash, as well as color, hardness (maximum force recorded in the first penetration or compression cycle) and chewiness index (energy required to chew food, given by gumminess x elasticity). Tuberous roots grown at 837 m altitude, independent of planting times, presented higher soluble solids content and lighter juice, conferring better quality. However, at 113 m altitude, from April to July, the roots showed better quality, since it presents lower hardness and lighter juice.

scholarly journals A New Silver Complex with Ofloxacin – Preliminary Study

2016 ◽  
Vol 62 (2) ◽  
pp. 192-198 ◽  
Author(s):  
Aura Rusu ◽  
Gabriel-Cosmin Popescu ◽  
Silvia Imre ◽  
Valentin Ion ◽  
Szende Vancea ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Chemical Structure ◽  
Chemical Characterization ◽  
Silver Complex ◽  
Stoichiometric Ratio ◽  
Scanning Calorimetry ◽  
Thermal Methods ◽  
Physico Chemical ◽  
Preliminary Study

AbstractObjective: Silver complexes of antibacterial quinolones have the potential advantage of combining the antibacterial activity of silver and fluoroquinolones. The objective of our study was the preparation and the preliminary physico-chemical characterization of a silver complex with ofloxacin.Methods: To achieve our goals several spectroscopic methods (ultraviolet spectrophotometry, mass spectrometry, and Fourier transform infrared spectroscopy) and thermal methods (differential scanning calorimetry and thermogravimetric analysis) were used in order to elucidate the chemical structure of the complex.Results: Using mass spectrometry we established the stoichiometric ratio silver:ofloxacin as 1:2. Experimental data suggest a particular coordination for ofloxacin, as a monodentate ligand, in the formation of a complex with silver, through the nitrogen atom from the methyl-piperazine cycle.Conclusions: The obtained complex has a chemical structure likely [Ag(Ofloxacin)2]NO3, requiring evaluation through other physico-chemical methods.

scholarly journals Partial Chemical Characterization of Immunomodulatory Polysaccharides from Plantago palmata Hook. f. s. Leaves

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Gabriel Biringanine ◽  
Moustapha Ouedraogo ◽  
Bernard Vray ◽  
Anne Berit Samuelsen ◽  
Pierre Duez
Keyword(s):  
Chemical Structure ◽  
Chemical Characterization ◽  
Biologically Active ◽  
Size Exclusion ◽  
Plantago Major ◽  
Activated Macrophages ◽  
Exclusion Chromatography ◽  
Very High ◽  
Partial Chemical

A previous work on Plantago palmata polysaccharides (PS) attributed immunomodulatory properties of leaves to a polysaccharide fraction (PS50) that stimulated NO and TNF-α production by interferon gamma- (IFN-γ-) activated macrophages. The present work aims to elucidate the chemical structure of these immunomodulatory polysaccharides. Size exclusion chromatography showed that the active polymers present an active fraction with a very high molecular weight (about 1200 kDa). These polysaccharides are pectic in nature, with a predominantly unbranched galacturonan domain and with a domain bearing side chains that consist of highly branched arabinan, galactan, and/or arabinogalactan. Comparatively to the well-known Plantago major biologically active PS, Plantago palmata PS50 contained less arabinogalactan-proteins (AGPs) and had a different composition in glucose, galactose, and galacturonic acid. DNA contamination of the polysaccharide was estimated at about 0.04%, a concentration much lower than those reported immunomodulatory in hyaluronic acid preparations (3 to 15%). Therefore, the eventuality of a contaminating DNA-mediated biological activity could be ruled out.

scholarly journals Morphological and chemical characterization of fruits of Capsicum spp. accessions

2011 ◽  
Vol 29 (3) ◽  
pp. 364-371 ◽  
Author(s):  
Elizanilda R do Rêgo ◽  
Mailson M do Rêgo ◽  
Izadora Wally F de Matos ◽  
Lidiany Aparecida Barbosa
Keyword(s):  
Dry Matter ◽  
Chemical Characterization ◽  
Matter Content ◽  
Breeding Program ◽  
Soluble Solids ◽  
Dry Matter Content ◽  
Capsicum Frutescens ◽  
Fresh Market ◽  
Capsicum Spp

This study aimed to evaluate 69 Capsicum accessions from the Germplasm Bank of Universidade Federal de Roraima, for some fruit quality traits. The experiment was performed in a completely random design, with 69 treatments and 3 replications. The 69 accessions were evaluated for fourteen quantitative and two qualitative traits of ripe fruits. Quantitative fruits data were subjected to an analysis of variance, and the means were grouped by Scott-Knott test (p<0.01). All characteristics had significant effect of treatments (p<0.01) for all evaluated traits. The data showed high genetic variability to future use in a Capsicum breeding program. The accessions 33, 44 and 41 showed major values for dry matter content and total soluble solids; these should be used to improve these traits in a paprika breeding program. On the other hand, the accession 48 showed major values for fresh weight, major fruit length and fruit width. The accession 33, belonging to the Capsicum frutescens species, with high vitamin C content should be used in a fresh market Capsicum breeding program.

Characterization of Physical and Chemical Evaluation on Six Apple Varieties

2013 ◽  
Vol 807-809 ◽  
pp. 1954-1959
Author(s):  
Li Yan Gong ◽  
Bin Li ◽  
Jin Feng Bi ◽  
Sha Sha Bai ◽  
Xian Jun Meng
Keyword(s):  
Chemical Properties ◽  
Chemical Characterization ◽  
Principal Component ◽  
Hierarchical Cluster ◽  
Soluble Solids ◽  
Physical And Chemical Properties ◽  
Apple Varieties ◽  
Physical And Chemical ◽  
And Chemical Properties

Physical and chemical characterization of 6 apple varieties (Early Golden Delicious, Jonagold, Hanfu, Ralls, Rainier and Fuji) from China was performed using pattern recognition tools. Measurements were taken on 12 parameters including weigh, colour, fruit firmness, crude fiber, total soluble solids, titration acid, water, Vitamin C, edible rate and juice yield .The results showed that physical and chemical properties existed different variance in apple varieties. The coefficient of variance of 12 properties was from 2.15% to 69.04%. The different apple varieties were investigated by principal component analysis (PCA) and hierarchical cluster analysis (HCA). PCA revealed that the first four components represented 95.13% of the total variability in properties and different apple groups. HCA classified samples into three groups on the basis of the physical and chemical properties.

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