Carboxylic Acid Compounds Research Articles

Effect of long-term moderate exercise on muscle cellularity and texture, antioxidant activities, tissue composition, freshness indicators and flavor characteristics in largemouth bass (Micropterus salmoides)

Fish fillet is heavily influenced by swimming exercise and other factors leading to a great change in fish physiology. During the present study, muscle cellularity, texture and composition, antioxidant activities and flavor characteristics were assessed and compared between non-exercised (N-EXF) and long-term exercised Largemouth bass. Exercised fish (EXF) showed improve in muscle cellularity and texture with high protein, hydroxyproline, collagen and low crude lipid compared to N-EXF. In addition, EXF showed Higher INOS, T-AOC, CAT and lower MDA, indicating high antioxidant activities in EXF compared to N-EXF. Furthermore, EXF showed lower hydrocarbons and alcohols content but higher in carboxylic acid, esters and aromatic compounds content compared N-EXF. EXF also showed lower TMAO, TMA, HX and high IMP content, indicating better freshness. Generally, EXF largemouth bass should be preferred depends on its high nutrition value, better flesh and freshness quality; and pleasant flavor.

Polyethyleneimine Functionalized Multi-walled Carbon Nanotubes-Based Solid Phase Extraction for Selective Screening of Carboxylic Acid Compounds in Natural Products

In this work, by adopting polyethyleneimine functionalized multi-walled carbon nanotubes as the absorbent, a solid phase extraction based method for fast and selective screening of carboxylic acid compounds was developed. The structure and morphology of the polyethyleneimine functionalized multi-walled carbon nanotubes were confirmed via scanning electron micrograph, transmission electron microscopy, Fourier transform infrared spectra and X-ray photoelectron spectroscopy. And the proposed approach was successfully applied to screen carboxylic compounds from the crude extract of Perilla frutescens. As a result, seven polyhydric compounds with carboxyl including caffeic acid, luteolin-7-O-diglucuronide, apigenin-7-O-diglucuronide, sagerinic acid, scutellarein-7-O-glucuronide, rosmarinic acid, and apigenin-7-O-glucuronide were favorably screened out from compounds without carboxyl group. Similar screening results were also obtained via generalizing the method to the crude extract of Chrysanthemum. This strategy could serve as a rapid and efficient pathway for preliminary screening of certain types of compounds from complex natural products.

Designing of acyl sulphonamide based quinoxalinones as multifunctional aldose reductase inhibitors.

A series of quinoxalinone scaffold-based acyl sulfonamides were designed as aldose reductase inhibitors and evaluated for aldose reductase (ALR2)/aldehyde reductase (ALR1) inhibition and antioxidation. Compounds 9b-g containing styryl side chains at C3-side exhibited good ALR2 inhibitory activity and selectivity. Of them, 9g demonstrated the most potent inhibitory activity with an IC50 value of 0.100 μM, and also exhibited excellent antioxidant activity, even comparable to the typical antioxidant Trolox. Compounds 9 had higher lipid-water partition coefficients relative to the carboxylic acid compounds 8, indicating that they may have better lipophilicity and membrane permeability. Structure-activity relationship (SAR) studies found that acyl trifluoromethanesulfonamide group at N1 and the C3-dihydroxystyryl side chain were the key structure for improving the aldose reductase inhibitory activity and antioxidant activity.

Hydrodeoxygenation of Octanoic Acid over Supported Ni and Mo Catalysts: Effect of Ni/Mo Ratio and Catalyst Recycling

AbstractHydrodeoxygenation of octanoic acid over supported NiMo bimetallic catalysts was investigated as a representative of carboxylic acid compounds in bio‐oils. A series of MCM‐41supported Ni and Mo bimetal catalysts were prepared with the wetness impregnation method. The microstructural and physicochemical properties of the fresh and recovered bimetal catalysts were characterized by various methods such as X‐ray diffraction (XRD), Scanning electron microscopy (SEM) and X‐ray photoelectron spectroscopy (XPS), etc.. The results show that the bulk NiO particles were well‐uniformly dispersed on the surface of the bimetal catalyst, and Mo4+ was founded as the main valence of Mo inside solid. Under the optimal conditions, i. e. the reaction temperature of 270 °C, reaction pressure of 3 MPa, and reaction time of 7 h, the 3Ni7Mo/MCM‐41 sample exhibits selectivity to octane 72.6% with a high conversion of octanoic acid 96.1%. Only a slight decrease in catalytic activity was observed after reused for three times. Moreover, the recovered sample was easily regenerated only with simple calcination and deoxidization, but has the similar microstructure compared with the fresh one.

Influence of the Treatment of Nonbonded Interactions on the Thermodynamic and Transport Properties of Pure Liquids Calculated Using the 2016H66 Force Field.

The effect of different treatments of the nonbonded interactions in simulations employing the recently introduced GROMOS-compatible 2016H66 force field is evaluated based on calculations carried out with the GROMACS software. This is done considering four thermodynamic and transport properties (pure liquid density, vaporization enthalpy, surface-tension coefficient, and self-diffusion constant) of 58 organic liquids representative of the chemical groups alcohol, ether, aldehyde, ketone, carboxylic acid, ester, amine, amide, thiol, sulfide, disulfide, and aromatic compounds, also including water (SPC model). A dipalmitoylphosphatidylcholine bilayer system is considered as well. The simulated properties are found to be very sensitive to the treatment of the long-range dispersion interactions, notably for the least polar systems. In general, the treatment of the long-range electrostatic or Lennard-Jones interactions using homogeneous correction terms or lattice-sum approaches yield similar results, with punctual discrepancies. The combination of a lattice-sum approach for the electrostatic interactions with a straight-cutoff truncation of the Lennard-Jones interactions at a distance of at least 1.2 nm is found to represent a good compromise setup within GROMACS for achieving compatibility with the reference results obtained using GROMOS as well as a comparable level of agreement with the experimental data. This study also reveals two potential issues with the GROMACS software, related to an incorrect calculation of the pressure when using LINCS in version 4.0.7 and an inadequate implementation of the twin-range scheme in version 5.1.2.

Determination of 10 perfluorinated carboxylic acid compounds in water by gas chromatography-mass spectrometry coupled with negative chemical ionization

A method was developed for the simultaneous determination of 10 perfluorinated carboxylic acid compounds in water by gas chromatography-mass spectrometry coupled with negative chemical ionization (GC-NCI-MS). Perfluorinated carboxylic acid compounds were derivatized by trifluoro-N-methyl-N-(trimethylsilyl) acetamide (MSTFA) as the trimethylsilyl derivatization reagent. The water sample was purified and enriched through a weak anion exchange solid phase extraction column and analyzed via GC-NCI-MS. The sample pretreatment, derivation and instrument conditions were optimized. The results showed that the linearity of the 10 perfluorinated carboxylic acid compounds was good in the range of 0.1-10 mg/L with correlation coefficients of 0.9956-0.9993. The limits of detection (LODs) and limits of quantification (LOQs) were 0.5-1.5 μg/L and 1.5-4.5 μg/L, respectively. The spiked recoveries of the blank samples ranged from 70.2% to 112.6% with the relative standard deviations (RSDs) between 2.1% and 14.5% (n=6). The method is simple, sensitive, accurate and precise, and can be used to detect the 10 perfluorinated carboxylic acid compounds in water.

Conversion of lignin into renewable carboxylic acid compounds by advanced oxidation processes

The present study was designed to investigate formation of possible carboxylic acids from oxidation of lignin by Fenton and UV-Fenton advanced oxidation processes (AOPs). The study was performed with model lignin monomers (syringaldehyde (SA), 4-hydroxybenzaldehyde (4-HBA), 2-methoxyphenol (2-MP) and 2,6-dimethoxyphenol (2,6-DMP)) and also with lignin isolated from eastern red cedar. Products in samples withdrawn from the reactor mixture at different oxidation stages were determined by GC-MS. Oxidation of one of lignin monomer (2-MP) was also performed with a different AOPs (UV/TiO2) for comparison of oxidation products.Depending on the oxidation stages, various carboxylic acids having aromatic and non-aromatic structures with mono- or di-carboxyl functional groups were determined. Performing oxidation of 2-MP with UV/TiO2 led to formation of 2-hydroxypropanoic acid as a low-carbon chain monocarboxylic acid which was not formed in Fenton and UV-Fenton. Oxidation products from the lignin fraction had mono- and di-carboxylic acid products in low percentages.

Ion Chromatography Method of Four Carboxylic Acids in Workplace Air

Objective: To assess psychological acceptance and occupational stress of medical staff, analyze the relationship among personality, psychological acceptance and occupational stress and discuss the direct or indirect effects of personality to occupational stress. Methods: The gaseous four kinds of carboxylic acids in the workplace air were simultaneously collected by silica gel tube, and then desorbed by deionized water and eluted by ion chromatograph. The the content was detected by conductivity detector. Results: The linear relationship was good in the concentration range of about 0~140 mg/L. The correlation coefficient r>0.999, and the maximum detection limit was 4.5 μg/mL. The sampling efficiency of the four carboxylic acids ranges from 96.10%~100.27%. Through the sample added recovery experiments, the low and high content of the silicone tube samples were detected; and the range of desorption efficiency was 82.18%~100.12%; the range of precision was 0.70%~3.71%. Conclusion: This method adopts deionized water to desorb samples, and the application of ion chromatography detection have reached the requirements of《Guidelines for the establishment of occupational health standards, Part 4: Determination of chemical substances in workplace air》, which can be used in four kinds of workplace air detection of carboxylic acid compounds.

Growth Rate and Chemical Composition of Secondary Metabolite Extracellular Polysaccharide (EPS) in Microalga Porphyridium cruentum

Porphyridium cruentum microalgae have great potential to be developed as a source of active ingredients in various fields of health. It excretes secondary metabolites in the form of extracellular polysaccharides (EPS), potentially as antibacterial, antihyperglycemic, and immunostimulant components. This study aims to obtain the best culture density of P. cruentum , the active component of P. cruentum (EPS), and the chemical composition of EPS. The P. cruentum was cultivated on 15%, 20% and 25% culture stock, with an addition of silicate, Fe and vitamins in sterile seawater medium with salinity 35‰, pH 8, temperature 25-27°C, with continuous aeration and 2500 lux continuous 24 hours, for 14 days of culture period. The results of this study indicate differences in growth rates and abundance of microalgae to each culture stock. The 15%, 20% and 25% culture stocks each showed stationary phase at days 10 th , 12 th and 14 th , with EPS concentrations of 10 ppt, 12 ppt, and 15 ppt, respectively. Variation of P . cruentum culture showed different EPS results, with a density of 25% capable of producing the highest EPS extract of 15,000 mg.L -1 . The EPS is known to contain glucose and carboxylic acid compounds that can be utilized in the health and industrial fields. Keywords: culture, extracellular polysaccharides, Porphyridium cruentum .

A techno-economic assessment of the potential for combining supercritical water oxidation with ‘in-situ’ hydrothermal synthesis of nanocatalysts using a counter current mixing reactor

A combined process of supercritical water oxidation (SCWO) and supercritical water hydrothermal synthesis (SCWHS) in a continuous counter current reactor is reported. Acrylic acid was used as a model unsaturated carboxylic acid compound and the effects of the reaction temperature, residence time, oxidant ratio and acrylic acid concentration on chemical oxygen demand (COD) were all investigated. Two different experimental configurations for oxidant delivery were carried out in ‘pre-heated’ and ‘non-preheated’ oxidant configurations. With a stoichiometric excess of 100% oxygen, COD reduction levels of 80% (non-preheated) and 15% (preheated) were achieved with very short residence times. SCWHS was achieved through the addition of small amounts of various soluble metal salts in the cold upflow resulted in nanoparticles forming which increased the reaction rate and hydrothermal oxidation efficiency. The addition of small amounts of chromium nitrate (>5mM) results in nearly 100% COD reduction at 380 °C and residence times of 0.75 s. The potential economic benefits of combining the two processes together, in the different configurations, were also evaluated.

Paradigm Shift for Preparing Versatile M2+-Free Gels from Unmodified Sodium Alginate.

This manuscript describes a new route to prepare rapidly Ca2+-free hydrogels from unmodified sodium alginate by simply mixing with small organic molecules such as poly(carboxylic acid) compounds as cross-linker agents instead of classical divalent metal salts such as CaCl2. Dimethyl sulfoxide (DMSO) was also found to induce the rapid gelation of aqueous alginate solutions. The gelation process takes place at room temperature, and depending on the composition, gels with good thermal (90-100 °C) and mechanical properties compared to classical metal-containing analogs are obtained. DMSO-based gels showed remarkable self-supporting and thixotropic properties, which can be tuned by the biopolymer concentration. Furthermore, oxalic acid-based gels show superior elasticity than HCl, CaCl2 and DMSO-based gels. The possibility to prepare monoliths, beads, and films of these gels provide them with significant versatility. In particular, films made of alginate and oxalic acid show good potential as synergistic anticancer drug delivery carrier. Computational studies using both quantum mechanical and classical force-field methodologies reveal that hydrogen bonding networks between water and DMSO molecules located close to the alginate chains are responsible for the stability of DMSO-based gels. In contrast, the cohesion of oxalic acid-based gels is a consequence of the coexistence of multiple ionic associations involving oxalate, alginate, and Na+ counterions, which stabilize the system and keep all the interacting species grouped.

Performance Analysis of Photolytic, Photocatalytic, and Adsorption Systems in the Degradation of Metronidazole on the Perspective of Removal Rate and Energy Consumption

The efficiency of the following systems: photolysis (UV-C only), photocatalysis with titanium-dioxide (UV-C/TiO2), photocatalysis with granular-activated carbon (UV-C/GAC), and by adsorption on GAC, was assessed under different initial contaminant concentrations, i.e., 0.1–100 mg L−1. The experiments were conducted in a batch photocatalytic reactor (1.9 L and 32 W UV power). It was found that UV-C/TiO2 and UV-C/GAC systems showed fairly equal removal efficiencies under lower MNZ concentrations (0.1–5 mg L−1) compared to higher concentrations at similar catalyst loading of 2.5 g L−1. A decline in removal rate (based on first-order reaction) was observed with respect to increase in initial MNZ concentration in all systems. MNZ removal by adsorption on GAC was much lesser compared to UV-C only, UV-C/TiO2, and UV-C/GAC systems. The adsorption data well correlated with the Freundlich model indicated that the adsorption was on the heterogeneous surface of the catalyst. The effectiveness of the systems were evaluated by calculating electrical energy consumed per order (E EO). The lowest E EO value was found to be for UV-C/TiO2 (0.03 kWh m−3 order−1) for the degradation of 0.1 mg L−1 of MNZ compared to UV-C/GAC (0.06 kWh m−3 order−1), UV-C only (0.15 kWh m−3 order−1), and adsorption (0.44 kWh m−3 order−1). The total organic carbon and nitrogen ion analyses have confirmed the mineralization of MNZ via aliphatic carboxylic acid compounds in the photocatalytic system. Overall, the photocatalytic system seems to be an energy-efficient treatment option for the removal of MNZ and similar other micropollutants.

Two-dimensional correlation spectroscopic analysis on the interaction between humic acids and aluminum coagulant

In this study, two-dimensional correlation spectroscopy integrated with synchronous fluorescence and infrared absorption spectroscopy was employed to investigate the interaction between humic acids and aluminum coagulant at slightly acidic and neutral pH. Higher fluorescence quenching was produced for fulvic-like and humic-like fractions at pH5. At pH5, the humic-like fractions originating from the carboxylic acid, carboxyl and polysaccharide compounds were bound to aluminum first, followed by the fulvic-like fractions originating from the carboxyl and polysaccharide compounds. This finding also demonstrated that the activated functional groups of HA were involved in forming the Al-HA complex, which was accompanied by the removal of other groups by co-precipitation. Meanwhile, at pH7, almost no fluorescence quenching occurred, and surface complexation was observed to occur, in which the activated functional groups were absorbed on the amorphous Al(OH)3. Two-dimensional FT-IR correlation spectroscopy indicated the sequence of HA structural change during coagulation with aluminum, with IR bands affected in the order of COOH>COO−>NH deformation of amide II>aliphatic hydroxyl COH at pH5, and COO−>aliphatic hydroxyl COH at pH7. This study provides a promising pathway for analysis and insight into the priority of functional groups in the interaction between organic matters and metal coagulants.

Multipoint recognition of domoic acid from seawater by dummy template molecularly imprinted solid-phase extraction coupled with high-performance liquid chromatography

Due to the high cost of domoic acid (DA), different carboxylic acid compounds including indole-3-acetic acid (IAA), pyrrole-2-formic acid (PFA), pyridine-2,3-dicarboxylic anhydride (PDA), trimesitinic acid (TA) and citric acid (CA) were investigated as dummy templates for the molecularly imprinted solid-phase extraction (MISPE) for selective isolation and pre-concentration of an amnesic shellfish poison (ASP), DA. The highest binding amount of the polymers towards DA was obtained when CA was used as dummy template owing to its high hydrophilicity. In addition, the “four-point” recognition site constructed by three COOH groups and a OH group in CA was also speculated to be the reason for the high binding amount of CA-MIPs and the rebinding of DA can be depend on the three COOH groups and a NH group with conformational change in the recognition process. Finally, the CA-MISPE column was chosen for DA isolation and pre-concentration and effective result was obtained with recoveries higher than 90% and relative standard deviation (RSD) less than 5% (n=3). This new polymer can be effectively applied to the monitoring and predicting the existence of trace DA.

Identification of flavor compounds in rambutan seed fat and its mixture with cocoa butter determined by SPME-GCMS

Rambutan (Nephelium opossum L) is one of the most important tropical fruits that is originally found in Malaysia, Thailand, Philippines, Vietnam, Borneo and other countries in this region. The industrial processing of this fruit produces seeds and peels as waste materials. The aim of this work was to determine the flavor active compounds of rambutan seed fat (RSF) and its mixtures with cocoa butter (CB) after fermentation 6days and roasting at 150°C for 30min in term of ester, alcohol, hydrocarbon, carboxylic acid, aldehyde, ketone and pyrazine compounds. The result showed total ester flavoring compounds increased in the range of 10.59%–16.49% in the RSF mixtures as compared to CB. Alcoholic flavoring compounds also found in the range of 10.03%–23.15% of the total flavor in CB and RSF mixtures respectively. The most important flavoring compounds, Pyrazine, 2,6-dimethyl (1.42% and 2.01%), Pyrazine, 2-ethyl-6-methyl (0.67% and 0.62%), Pyrazine, trimethyl (5.10% and 5.22%), Pyrazine, tetramethyl (14.34% and 14.72%), 2-Acetyl-3,5-dimethylpyrazine (0.56% and 0.45%), 2-Isoamyl-6-methylpyrazine (0.34% and 0.34%) and Pyrazine, 2-butyl-3,5-dimethyl (0.34% and 0.27%) estimated in CB and RSF mixtures respectively. Rambutan seed fat up to 20% can be used with cocoa butter as a potential ratio of CB and RSF for the application in chocolate manufacturing as a cocoa butter alternative to improve and get the best quality aroma in final products.

Variation of the microbiota and metabolome along the canine gastrointestinal tract

The fecal microbiota are relevant to the health and disease of many species. The importance of the fecal metabolome has more recently been appreciated, but our knowledge of the microbiota and metabolome at other sites along the gastrointestinal tract remains deficient. To analyze the gastrointestinal microbiota and metabolome of healthy domestic dogs at four anatomical sites. Samples of the duodenal, ileal, colonic, and rectal contents were collected from six adult dogs after humane euthanasia for an unrelated study. The microbiota were characterized using Illumina sequencing of 16S rRNA genes. The metabolome was characterized by mass spectrometry-based methods. Prevalent phyla throughout the samples were Proteobacteria, Firmicutes, Fusobacteria, and Bacteroidetes, consistent with previous findings in dogs and other species. A total of 530 unique metabolites were detected; 199 of these were identified as previously named compounds, but 141 of them had at least one significantly different site-pair comparison. Noteworthy examples include relative concentrations of amino acids, which decreased from the small to large intestine; pyruvate, which peaked in the ileum; and several phenol-containing carboxylic acid compounds that increased in the large intestine. The microbiota and metabolome vary significantly at different sites along the canine gastrointestinal tract.

An Application of Gas Chromatography-Mass Spectrometry (GC-MS) Fast Automated Scan/SIM Type (FASST) in Determining the Preservative Levels in Foods

The preservatives used in food products are strictly monitored and regulated. The present study aims to imply a sensitive and reliable analytical method to quantify two classes of preservatives (i.e. carboxylic acid and phenolic compounds) in food by means of gas chromatography-mass spectrometry (GC-MS), aimed at monitoring the products available within the local stores. Target analytes were derivatized via aqueous-phase isobutyl chloroformate-mediated reaction followed by dispersive liquid-liquid microextraction (DLLME) method. The quantity and quality determination of the studied samples were assured by performing FASST approach in a single run GC-MS analysis. The combination of standard addition method with sample dilution compensated the effect of sample matrix on the quantitative determination of the tested preservatives in the examined samples. The concentrations of sorbic acid (SA) were 210 μg/mL and 1000 μg/mL in soft drink and sauces samples, respectively. On the other hand, sodium benzoate (226 μg/mL) was only found in soft drink, whereas, no parabens were detected in any samples collected from the local stores.

Chromium recovery from tannery sludge by bioleaching and its reuse in tanning process

Bioleaching has been demonstrated as a feasible and effective technology for removing Cr(III) from tannery sludge, but the recovery of bioleachate derived from tannery sludge by bioleaching is rarely reported. The purpose of this study was therefore to figure out the components of bioleachate and develop a chromium-iron tanning agent using the bioleachate and reuse it in tanning process. Component analysis indicated that the bioleachate contained high concentrations of Cr and Fe, as well as small quantities of other elements. The dissolved organic matter in the bioleachate was detected to be less than 1000 mg/L, which was mainly composed of polysaccharide, aliphatic or aromatic carboxylic acid compounds. A chromium-iron tanning agent was then prepared using the bioleachate, iron and chromium salts in a suitable ligand environment, and reused for tanning. In the tanning experiments, the pickled pigskins were tanned with this prepared tanning agent and the results indicated that chromium-iron tanned crust leather presented comparable physical and mechanical properties as well as air permeability when compared with conventional chromium tanned crust leather, but the thermal shrinkage temperature was about 4 °C lower than that of the chromium tanned crust leather. Therefore, this study provides not only a reuse route for tannery sludge bioleachate but also a clean tanning agent for leather processing.

Rapid bioremediation of Alizarin Red S and Quinizarine Green SS dyes using Trichoderma lixii F21 mediated by biosorption and enzymatic processes.

In this study, a newly isolated ascomycete fungus Trichoderma lixii F21 was explored to bioremediate the polar [Alizarin Red S (ARS)] and non-polar [Quinizarine Green SS (QGSS)] anthraquinone dyes. The bioremediation of ARS and QGSS by T. lixii F21 was found to be 77.78 and 98.31%, respectively, via biosorption and enzymatic processes within 7days of incubation. The maximum biosorption (ARS=33.7% and QGSS=74.7%) and enzymatic biodegradation (ARS=44.1% and QGSS=23.6%) were observed at pH 4 and 27°C in the presence of glucose and yeast extract. The laccase and catechol 1,2-dioxygenase produced by T. lixii F21 were involved in the molecular conversions of ARS and QGSS to phenolic and carboxylic acid compounds, without the formation of toxic aromatic amines. This study suggests that T. lixii F21 may be a good candidate for the bioremediation of industrial effluents contaminated with anthraquinone dyes.

Phytochemical Analysis of <I>Meizotropis pellita</I> by FTIR and UV- VIS Spectrophotometer

Objective: The present study investigates the characterization of the bioactive constituents showing antimicrobial activity present in leaf extract of Meizotropis pellita using UV-VIS and FTIR spectroscopy. Method: The methanolic extract of the leaves of Meizotropis pellita prepared by cold maceration method and analysed under ultraviolet and visible light. The scanning of the crude extract was done at the range from 190‐800 nm through Varian Cary -100 UV Visible spectrophotometer system and the characteristic peaks were detected. FTIR studies was done on a Jasco-4100 system, ranging 4000-400 cm -1 which revealed the characteristic peak values showing the absorption and functional groups present in leaf extract. Findings: The UV-VIS profile showed the peaks at 660, 340, 270, 235 and 210 nm with the absorption 0.085, 1.250, 2.605, 4.455 and 3.639. The result of FTIR spectra confirms the presence of alcohol, aldehydes carboxylic acid, aromatic and halogen compounds. So the present study provide evidences that leaves of Meizotropis pellita contain bioactive constituents which could be of interest for the development of new drug.