Abundant Chemical Groups Research Articles

Characterization of Fast Pyrolysis Bio-Oil from Hardwood and Softwood Lignin

The depletion of fossil fuel reserves and the increase of greenhouse gases (GHG) emission have led to moving towards alternative, renewable, and sustainable energy sources. Lignin is one of the significant, renewable and sustainable energy sources of biomass and pyrolysis is one of the most promising technologies that can convert lignocellulosic biomass to bio-oil. This study focuses on the production and characterization of bio-oil from hardwood and softwood lignin via pyrolysis process using a bench-scale batch reactor. In this study, a mixed solvent extraction method with different polarities was developed to fractionate different components of bio-crude oil into three fractions. The obtained fractions were characterized by using gas chromatography and mass spectrometry (GCMS). The calculated bio-oil yields from Sigma Kraft lignin and Chouka Kraft lignin were about 30.2% and 24.4%, respectively. The organic solvents, e.g., toluene, methanol, and water were evaluated for chemical extraction from bio-oil, and it was found that the efficiency of solvents is as follows: water > methanol > toluene. In both types of the bio-oil samples, phenolic compounds were found to be the most abundant chemical groups which include phenol, 2-methoxy, 2-methoxy-6-methylphenol and phenol, 4-ethyl-2-methoxy that is due to the structure and the originality of lignin, which is composed of phenyl propane units with one or two methoxy groups (O-CH3) on the aromatic ring.

Determination of Antioxidant Value and Chemical Groups in Selected Medicinal Plants Used for Conditions Associated with Herpes Simplex and Herpes Zoster Infections in Kakamega County, Kenya

Aims: To Determine antioxidant value and chemical groups in selected medicinal plants used for conditions associated with Herpes simplex and Herpes zoster infections in Mukhwa sub-location, Kakamega County, Kenya.
 Study Design: A qualitative ethnobotanical survey for plant identification and chemical analysis for antioxidant assay and chemical group detection.
 Place and Duration of Study: Plant samples were collected in Mukhwa sub-location in September 2014. Sample processing and chemical group detection was carried out at the Center of Traditional Medicine and Drug Research of Kenya Medical Research Institute. Antioxidant assay was carried out at the Department of Medical Laboratory Sciences of the Kenya Medical Training College.
 Methodology: All 12 Community Health Workers, comprising 7 females and 5 males, were interviewed for identification of plant species. Antioxidant assay was carried out using the 2,2-Diphenyl-1-picrylhydrazyl (DPPH) reduction assay and detection of flavonoids, terpenoids, alkanoids, saponins and phenols carried out using physicho-chemical methods.
 Results: Caesalpinia decapetala, Garcinia buchananii and Entada abyssinica, were the most potent sources of antioxidant with the concentration giving 50% DPPH reduction (RSa50) of 50, 20 and 10 µg/ml, respectively. The most abundant chemical groups were; alkaloids in Schkuhria pinnata, terpenoids in E. abyssinica, flavonoids in G. buchananii, the latter also contained the highest amount of phenols.
 Conclusion: The findings of antioxidant and chemical groups in selected medicinal plants support their use for HIV conditions.

Polydopamine Modified Graphene Oxide-TiO2 Nanofiller for Reinforcing Physical Properties and Anticorrosion Performance of Waterborne Epoxy Coatings

Nano-polydopamine-graphene oxide-TiO2 (nano-PDA@GO-TiO2) composites were prepared by dopamine modified graphene oxide (GO) and loaded nano-TiO2 on the surface of GO. The structure and morphology of nano-PDA@GO-TiO2 composites were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman, X-ray photoelectron spectroscopy (XPS), Scanning electron microscope (SEM), and Transmission electron microscope (TEM) Results demonstrate that the introduction of dopamine to functionalize the GO could self-polymerize polydopamine (PDA) on the surfaces of the GO and endow abundant chemical groups reduce the GO. The interaction between the GO and nano-TiO2 particles could prevent graphene nanosheets from restacking and nano-TiO2 particles from agglomeration. Nano-PDA@GO-TiO2 composite material was used as the nano-filler, and nano-PDA@GO-TiO2 composites waterborne epoxy resin coatings (PGT/WEP) were prepared by dispersing a different content of nano-PDA@GO-TiO2 composites into waterborne epoxy resin with the help of ultrasonic dispersion and mechanical agitation. The physical properties of PGT/WEP coatings, such as hardness, impact resistance, and adhesion, were tested and the electrochemical performance was evaluated. The results show that dispersing 2% nano-PDA@GO-TiO2 composites in waterborne epoxy resin could significantly improve the physical properties and corrosion resistance of waterborne epoxy resin coating when compared with pure waterborne epoxy coating.

Simultaneous elimination of multicomponent toxic industrial chemicals by Cu-carbon beads

Protecting the staff on site from exposure risk to toxic industrial chemicals (TICs) in an efficient way is of great significance. However, simultaneous removal of multicomponent TICs with different physical and chemical properties is a challenge for porous carbon materials. In this work, Cu-carbon beads with tailored porous structure and chemical property were synthesized via phase inversion-carbonization (PIC) route. The in-situ introduction of copper species was accomplished via coupling solidification-reduction of copper species and PIC process. The obtained Cu-carbon beads possessed uniform spherical shape (Φ1.3 mm) with good mechanical strength, developed porous structure and abundant chemical groups. Three kinds of TICs with different chemical properties, i.e. benzene (nonpolar), ethanol (polar) and H2S (inorganic), were selected as probes to evaluate the simultaneous elimination performance of Cu-carbon beads. The optimized Cu-beads-3 exhibited excellent performance for multicomponent TICs with capacities of 491.9 mg benzene/g, 192.1 mg ethanol/g and 76.2 mg H2S/g, representing 74.0, 60.3 and 99.2% capacities compared with monocomponent TICs. The enhanced adsorption of H2S were ascribed to chemisorption of copper species and basic groups on Cu-carbon beads. These results indicated that Cu-carbon beads would be a promising candidate for the simultaneous elimination of TICs with different chemical properties.

Influence of different pig genotype on aroma, colour and fatty acid composition of smoked dry-cured ham

The aim of this study was to determine the influence of different genotypes of pigs ((Landrace x large Yorkshire) x Duroc (LYD) and Black Slavonian (BS) pig) on the colour, fat content and fatty acid composition of smoked dry-cured ham and identify volatile aroma-active compounds. The fat content was determined by applying the Smedes method and the composition of fatty acids by using the gas chromatography, while volatile aroma-active compounds were investigated by using the headspace-solid phase microextraction (HS-SPME) and the gas chromatography-mass spectrometry (GC-MS). Different genotypes of pigs did not show a statistically significant difference (p>0.05) in total fat content, but there was a difference in the proportion of individual fatty acids. We identified a total of 103 volatile compounds belonging to the following groups of chemical compounds: 19 aromatic hydrocarbons, 17 aliphatic hydrocarbons, 17 ketones, 15 phenols, 14 aldehydes, 11 alcohols, 5 acids, 2 terpenes and 1 sulphur compound. The most abundant chemical groups of compounds in samples of smoked dry-cured ham from LYD pigs were aldehydes, phenols and aromatic hydrocarbons, while the most abundant chemical groups of compounds in samples of smoked dry-cured ham of BS genotype were phenols, aldehydes and alcohols.

Accumulation of flame retardants in paired eggs and plasma of bald eagles

In this study, we measured the concentrations of 58 flame retardants (and related compounds) in bald eagle (Haliaeetus leucocephalus) egg and plasma samples from the Michigan. These analytes include polybrominated diphenyl ethers (PBDEs), novel flame retardants (nFRs), Dechlorane-related compounds (Decs), and organophosphate esters (OPEs). A total of 24 paired eaglet plasma and egg samples were collected from inland (IN, N = 13) and the Great Lakes (GL, N = 11) breeding areas from 2000 to 2012. PBDEs were the most abundant chemical group with a geometric mean of 181 ng/g wet weight (ww) in egg and 5.31 ng/g ww in plasma. Decs were barely found in plasma samples, but they were frequently found in eggs (geometric mean 23.5 ng/g ww). OPE levels were comparable to those of PBDEs in the plasma but lower than those of PBDEs in eggs. Dec and PBDE concentrations were significantly higher in GL than in IN (p < 0.05). The ratio of egg to plasma concentrations (lipid normalized) varied with chemicals and correlated with the chemical's octanol-water partition coefficient. The lipid normalized bald eagle egg and plasma concentrations from Lake Superior and Huron were one to three orders of magnitude higher than concentrations measured in composite lake trout (Salvelinus namaycush) from the same lake, implying that they biomagnify in the environment.

Surface Modification of Graphene Oxide with Pyrene Derivatives and their Photo-Switching Behaviors

The characteristics of surface and interface of nanocomposites are favor for exerting some functional properties and widening new applications. Some low-dimensional materials generally have abundant chemical groups and reaction activities. These surface chemical groups of nanomaterials provide a large platform to develop new nanocomposites and applications by surface chemical reaction and surface reconstruction of another kind of materials. Among so many hot-fields materials, graphene and its nanocomposite are developed rapidly. The graphene oxide not only has good charge transferring property, but also has abundant chemical groups on its surface, such as, -COOH, -OH and epoxide group. Therefore, graphene oxide is a good candidate substrate for further constructing other functional materials in nanoscale. The graphene oxide and pyrene derivatives were selected as representative materials for studies. Assembly of pyrene containing –NH2 groups on the surface of graphene oxide was carried out. A series of characterizations were performed by SEM (scanning electron microscopy), TEM (transmission electron microscopy), the FTIR (Fourier-Transform Infrared ) spectra, The UV-Vis (Ultra-violet visible spectroscopy), photoluminescence spectra, et al. The results indicated that the UV-Vis of nanocomposite was almost covered the whole region of visible light, and the results of PL showed strong fluorescence quenching. There was strong interaction between the graphene oxide and pyrene. The photoconductivity response to weak visible light and 808 nm laser were studied based on interdigital electrodes of Au on flexible PET(polyethylene terephthalate) film substrate with casting method. The results showed that graphene oxide modified with pyrene derivatives exhibited that the photocurrent increased obviously to visible light, and photoresponse to weak 808 nm laser emerged photo-switching behavior. It would be developed the light detector to NIR, biomimetic fields or external stimuli driven nanocarriers for biomedical fields, et al.

Effects of rigorous emission controls on reducing ambient volatile organic compounds in Beijing, China

102 volatile organic compound (VOC) species were measured online using a gas chromatography–mass spectrometry/flame ionization detector (GC–MS/FID) at an urban site in Beijing in 11 August to 3 September 2015, when a series of rigorous air quality control measures were implemented in Beijing city and neighbouring provinces. Positive matrix factorization (PMF) was applied to identify emission sources from 1h averaged values of VOC data. Based on the online VOC data and the PMF analysis results, the effectiveness of different control measures were investigated. The PMF results were compared with an emission inventory data. Results show that the rigorous air quality restrictions implemented were successful. The averaged ambient VOC mixing ratios during the emission control period and non-control period were 27.53 and 45.42ppbv, respectively. The mixing ratios of total VOC during the control period were reduced by 40%. Alkanes were the most abundant chemical group in the two periods, followed by oxygenated volatile organic compounds (OVOCs). Almost all quantified VOC species decreased during the control period. Tracers of industrial sources and vehicle exhaust reduced most, including some halocarbons, esters and aromatics. Eight sources were resolved by online PMF analysis for ambient VOCs in Beijing. Contributions of those sources varied significantly during the control and non-control period. Compared with the values before control, contributions of vehicle-related sources were most reduced, followed by solvent utilization. Reductions of vehicle-related sources, solvent utilization, secondary formation, fuel combustion, and biogenic were responsible for 65%, 19%, 10%, 5%, and 1% of the reductions in ambient VOCs. Both PMF results and emission inventory data indicated that the control measure on traffic was very effective in reducing ambient VOCs in Beijing, with the emission reductions of about 50%.

DNA-carbon dots function as fluorescent vehicles for drug delivery.

Carbon dots (CDs) are a new representative in the carbon-based material family, attracting tremendous interest in a large variety of fields, including biomedicine. In this report, we described a facile and green system for synthesizing DNA-CDs using genomic DNA isolated from Escherichia coli. DNA-CDs can be purified using a simple column centrifugation-based system. During DNA-CD synthesis, ribose was collapsed, accompanied by the release of nitrogen, and several new bonds (C-OH, N-O, and N-P) were formed, while the other covalent bonds of DNA were largely maintained. The presence of abundant chemical groups, such as amino or hydroxyl groups on DNA-CDs, may facilitate their future functionalization. These highly biocompatible DNA-CDs can serve as a new type of fluorescent vehicle for cell imaging and drug delivery studies. Our research may hasten the development of CDs for prominent future biomedical applications.

Phytochemical composition of the essential oil of Prunella grandiflora

Prunella grandiflora (L.) Scholler, Lamiaceae, is a termophilous, European–W–Asiatic perennial herb which has been used traditionally as an external remedy for the treatment of wounds. Although the majority of Lamiaceae species are aromatic, as far as we know there is no report on the essential oil composition of P. grandiflora. Therefore, P. grandiflora essential oil was isolated by hydrodistillation and analysed by GC and MS. Total of 40 volatiles were identified, and two non-terpene compounds dominated in the oil: (E, E)-hepta-2, 4-dienal (17.8%) and phenylacetaldehyde (13.2%). Aliphatic aldehydes and alcohols were abundant in the oil: (E, E)-hepta-2, 4-dienal followed by (E)-hex-2-enal, (Z)-hex-3-en-1-ol, (E, E)-hexa-2, 4-dienal and oct-1-en-3-ol. Other abundant chemical group of identified volatile organic compounds constituted of oxygenated monoterpenes that contained ubiquitous essential oil constituents such as linalool (7%), trans-pinocarveol (6.5%), myrtenol (3.8%), terpinen-4-ol (3.2%), menthol (3%) and others. Beside phenylacetaldehyde, two isomers thymol (2.8%) and carvacrol (3.5%) were found among phenylpropane derivatives. Due to presence of oxygenated monoterpenes along with thymol and carvacrol that exhibit well known biological activity (such as antioxidant or antimicrobial) the essential oil could contribute to previously observed therapeutic application of the plant. Only few sesquiterpenes were found: α-copaene, (E)-β-caryophyllene, spathulenol and caryophyllene oxide. Unlike most aromatic plants, monoterpene hydrocarbons were hardly present (low percentages of β-pinene, p-cymene and (Z)-β-ocimene) among P. grandiflora L. volatile compounds. Comparison with constituents of the essential oil from three plants of Prunella (P. vulgaris L., P. asitica Nakai and P. hispida Benth.) revealed major differences.

Physico‐chemical characterisation of a non‐conventional food protein source from earthworms and sensory impact in arepas

SummaryThis study aimed to characterise a non‐conventional protein source: a powder made from earthworms, and to evaluate its potential use as human food. The way it was prepared led to low solubility and wide particle size distribution. Sensory analysis was used to assess the acceptability and the organoleptic properties of maize‐based pan‐cakes fortified with this novel protein powder. Satisfying products were obtained with a substitution level of 5.5% (w/w) earthworm powder in pan‐cakes. GC‐MS allowed the identification of more than seventy volatile compounds that may be responsible for the off‐odour of the powder. The most abundant chemical groups found in the volatile fraction were ketones with undecan‐2‐one, alcohols with pentan‐1‐ol, and aldehydes with hexanal. Partial delipidation was tested as a way to improve the organoleptic quality of the powder. It clearly led to less intensely coloured samples but delipidation must be optimised to have an impact on odour.

Indoor Volatile Organic Compounds in Atopy Patients' Houses in South Korea

This study was undertaken to determine the concentrations of volatile organic compounds (VOCs) in the indoor air of atopy patients' (atopic dermatitis 50, allergic asthma 36) and control houses (28 nonpatients). A goal of this study was also to investigate whether indoor VOCs were risk factors for the development of atopic sensitization. Eleven alkanes, 13 aromatics, 7 chlorinated hydrocarbons, 3 terpenes, and 15 aldehyds were measured from 10 March to 15 June, 2006. Aldehyde compounds are the most abundant chemical group in all indoor air, followed by aromatic compounds. The geometric mean concentrations of total VOC (TVOC) in indoor air in atopic dermatitis and allergic asthma patients' houses were 317.1 and 219.2 mg m -3, respectively. However, TVOC concentrations did not differ significantly between control and patient houses in indoor and outdoor air. The geometric mean concentrations of benzene, ethylbenzene ( p&lt;0.05), o-xylene, m-, p-xylene, styrene, levels of 1,3,5-trimethylbenzene and formaldehyde ( p&lt;0.01) in the indoor air of houses of patients with atopic dermatitis, and levels of o-xylene and 1,3,5-trimethylbenzene ( p&lt;0.01) in houses of allergic asthma patients were significantly higher than those in control houses. The multiple linear regression model in this study indicated several indoor origins of VOCs. House age and floor or wall coverings that had been refurbished within 1 year were correlated with higher concentrations of formaldehyde. Limonene and αpinene concentrations were significantly increased by the replacement of furniture and the use of cleaning products. The type of heating system was significantly associated with indoor benzene, toluene, ethylbenzene, nonane, decane, and undecane concentrations in atopy patient houses.

Volatile Constituents of Mandarin (Citrus reticulata Blanco) Peel Oil from Burundi

The essential oil constituents of mandarin (Citrus reticulata Blanco) grown in Burundi were extracted by cold-pressing method and analyzed by GC and GC/MS. Fifty-eight constituents, amounting to 97.2% of the total volatiles were identifed. Monoterpene hydrocarbons accounted for the most abundant chemical group (94.7%). Limonene was the most prominent constituent (84.8%), followed by γ-terpinene (5.4%), myrcene (2.2%) and α-pinene (1.1%). Sesquiterpene hydrocarbons accounted for a minor quantity (0.2%), where germacrene D and valencene were the main constituents. Oxygenated compounds of various chemical groups constituted 2.3%. Aliphatic aldehydes (0.7%) and terpene alcohols (0.7%) were the major chemical groups. The main constituents were linalool (0.7%), octanal (0.5%) and decanal (0.2%). Octyl acetate, α-sinensal, decanol and perillaldehyde occurred at 0.1% levels. Thymol, α-sinensal, methyl thymol, and the acetate esters, bornyl, α-terpinyl, geranyl, citronellyl and decyl acetates were detected, each at < 0.05%.

Characteristics of dissolved organic matter and phenolic compounds in forest soils under silver birch (Betula pendula), Norway spruce (Picea abies) and Scots pine (Pinus sylvestris)

SummaryThe aim was to characterize dissolved organic matter in soils under different tree species. Molecular size distribution and chemical composition of dissolved organic carbon and nitrogen were determined in water extracts from humus layers and mineral soils taken from silver birch (Betula pendula Roth.), Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.) stands. Concentrations of tannins and 15 phenolic acids in the humus layers were measured. Per unit of organic matter, the concentrations of dissolved organic C and N were larger in birch and spruce humus layers than in the pine humus layer. In the underlying mineral soil, the concentrations of dissolved organic C were similar at all sites, but the concentration of dissolved organic N was greater in spruce and pine soils than in birch soil. In all soils, the 10–100 kDa fraction was the most abundant molecular size group and hydrophobic acids the most abundant chemical group of dissolved organic C. In all humus layers, hydrophobic acids and hydrophilic bases were the major components of dissolved organic N. There were only minor differences in the concentrations of total tannins in the humus layers under different tree species. Small‐molecule tannins (about &lt; 0.5 kDa) were most abundant in the birch humus, and large‐molecule tannins in the pine humus. Coniferous humus contained more ferulic and p‐coumaric acids than did the birch humus. The concentrations of 3,4 and 3,5‐dihydroxybenzoic acid, vanillic acid and 4‐hydroxybenzoic acid were similar in all soils.