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https://www.readbyqxmd.com/read/29331796/determination-of-meropenem-in-endotracheal-tubes-by-in-tube-solid-phase-microextraction-coupled-to-capillary-liquid-chromatography-with-diode-array-detection
#1
L Hakobyan, J Pla Tolos, Y Moliner-Martinez, C Molins-Legua, Jesús Ruiz Ramos, M Gordon, Paula Ramirez-Galleymore, P Campins-Falco
Meropenem is a widely used antimicrobial for the treatment of infections associated with the use of invasive medical devices in intensive care unit patients. These treatments are not always effective, in fact, in-vitro studies have demonstrated the difficulty of antimicrobials to penetrate into the biofilm, however in-vivo studies of the effect of these compounds is a trend, mostly because of the complexity of pulmonary samples extracted from ETTs. Therefore, the objective of this study was to evaluate in-tube solid phase microextraction (in-tube SPME) coupled to capillary liquid chromatography (CapLC) with DAD to determine meropenem in ETTs in order to estimate the penetration capability into the biofilm...
January 8, 2018: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/29329873/preparation-and-characterization-of-citral-loaded-solid-lipid-nanoparticles
#2
Huaixiang Tian, Zhuoyan Lu, Danfeng Li, Jing Hu
Citral-loaded solid lipid nanoparticles (citral-SLNs) were prepared via a high-pressure homogenization method, using glyceryl monostearate (GMS) as the solid lipid and a mixture of Tween 80 (T-80) and Span 80 (S-80) at a weight ratio of 1:1 as the surfactant. The microstructure and properties of the citral-SLNs were characterized by dynamic light scattering (DLS), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermal gravimetric analysis (TGA)...
May 15, 2018: Food Chemistry
https://www.readbyqxmd.com/read/29329227/fermentation-guided-natural-products-isolation-of-a-grape-berry-triacylglyceride-that-enhances-ethyl-ester-production
#3
Christopher L Blackford, Eric G Dennis, Robert A Keyzers, Claudia Schueuermann, Robert D Trengove, Paul K Boss
A full understanding of the origin, formation and degradation of volatile compounds that contribute to wine aroma is required before wine style can be effectively managed. Fractionation of grapes represents a convenient and robust method to simplify the grape matrix to enhance our understanding of the grape contribution to volatile compound production during yeast fermentation. In this study, acetone extracts of both Riesling and Cabernet Sauvignon grape berries were fractionated and model wines produced by spiking aliquots of these grape fractions into model grape juice must and fermented...
January 12, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29313329/flavor-and-acceptance-of-roasted-california-almonds-during-accelerated-storage
#4
Lillian May Franklin, Ellena S King, Dawn Chapman, Nadia K Byrnes, Alyson Elayne Mitchell
Monitoring oxidative flavor changes in almonds is only possible if the chemical and sensory profile during roasting and storage is first established. Herein almonds roasted at two different temperatures (115 and 152 °C) were stored at 39 °C for 0 to 12 months and were analyzed by Headspace Solid-phase Microextraction Gas Chromatography-Mass Spectrometry (HS-SPME-GC/MS), descriptive analysis and consumer hedonic analysis. Volatile profiles, descriptive sensory profiles and consumer hedonic scores were analyzed for predictive relationships...
January 9, 2018: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/29306412/automated-and-simultaneous-determination-of-priority-substances-and-polychlorinated-biphenyls-in-wastewater-using-headspace-solid-phase-microextraction-and-high-resolution-mass-spectrometry
#5
Irene Domínguez, Francisco Javier Arrebola, Rafael Gavara, José Luis Martínez Vidal, Antonia Garrido Frenich
The re-use of wastewater has been in growing demand but a possible negative feature is the possibility of organic pollutants being present after its treatment. In order to control the presence of contaminants in wastewater, a completely automated methodology capable of determining a total of 55 organic pollutants including pesticides, polycyclic aromatic hydrocarbons (PAHs), brominated diphenyl ethers (BDEs) and polychlorinated biphenyls (PCBs) at ultra-trace levels has been developed. The proposed method is based on an on-line combination of headspace solid phase microextraction (HS-SPME) and gas chromatography coupled to double-focusing magnetic sector high resolution mass spectrometry (GC-HRMS)...
March 9, 2018: Analytica Chimica Acta
https://www.readbyqxmd.com/read/29306411/evaluating-solid-phase-micro-extraction-tools-to-analyze-freely-ionizable-and-permanently-charged-cationic-surfactants
#6
Niels Timmer, Peter Scherpenisse, Joop L M Hermens, Steven T J Droge
Working with and analysis of cationic surfactants can be problematic since aqueous concentrations are difficult to control, both when taking environmental aqueous samples as well as performing laboratory work with spiked concentrations. For a selection of 32 amine based cationic surfactants (including C8- to C18-alkylamines, C14-dialkyldimethylammonium, C8-tetraalkylammonium, benzalkonium and pyridinium compounds), the extraction from aqueous samples was studied in detail. Aqueous concentrations were determined using solid phase extraction (SPE; 3 mL/60 mg Oasis WCX-SPE cartridges) with recoveries of ≥80% for 30 compounds, and ≥90% for 16 compounds...
March 9, 2018: Analytica Chimica Acta
https://www.readbyqxmd.com/read/29291407/urine-volatile-organic-compounds-as-biomarkers-for-minimal-change-type-nephrotic-syndrome
#7
Desheng Liu, Nana Zhao, Mingao Wang, Xin Pi, Yue Feng, Yue Wang, Hongshuang Tong, Lin Zhu, Changsong Wang, Enyou Li
Urinary volatile organic compounds (VOCs) profiling has recently received considerable attention because it can be obtained noninvasively and conveniently while it can be successfully used in a variety of diseases and can provide unique biomarkers. The aim of current study was to investigate potential biomarkers between minimal change type nephrotic syndrome (MCNS) and normal. Urinary samples were collected from 38 minimal change type nephrotic syndrome patients and 15 healthy controls. Solid phase microextraction (SPME) and chromatography- mass spectrometry (GC-MS) were used to analysis the urinary metabolites...
December 29, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/29289906/variability-of-ethanol-concentration-in-rainwater-driven-by-origin-versus-season-in-coastal-and-inland-north-carolina-usa
#8
Katherine M Mullaugh, Megumi S Shimizu, Joan D Willey, J David Felix, Robert J Kieber, G Brooks Avery, Ralph N Mead, Callan Andreacchi, Aviya Payne
Rainwater ethanol concentrations were measured for one year (June 2013-May 2014) in central (Elon, NC) and coastal (Wilmington, NC) North Carolina, allowing for a comparison of the effects of coastal and marine rain on ethanol concentration and deposition both at the coast and 250 km inland. Rain samples were collected on an event basis and analyzed using enzyme oxidation and headspace solid-phase microextraction (HS-SPME). The volume-weighted average ethanol concentration at Elon (609 ± 116 nM) was higher than at Wilmington (208 ± 21 nM)...
December 21, 2017: Chemosphere
https://www.readbyqxmd.com/read/29287364/juice-volatile-composition-differences-between-valencia-orange-and-its-mutant-rohde-red-valencia-are-associated-with-carotenoid-profile-differences
#9
Xu Wei, Mei Song, Chunxian Chen, Huarong Tong, Guolu Liang, Fred G Gmitter
A targeted approach using HS-SPME-GC-MS was performed to investigate volatile compounds of ordinary Valencia (VAL) and its more deeply colored mutant Rohde Red Valencia orange (RRV) at different developmental stages. Fifty-six volatile components classified into six chemical groups were quantified. The individual volatile compounds in each group were significantly influenced by the genotype and harvest date. Cluster analysis suggested two principal clusters. Cluster I included fruits of VAL and RRV harvested in July, September, and November and was characterized by the 2-ethyl-1-hexanol acetate and linalool chemotype; cluster II included fruits harvested in January and March, with the valencene/β-myrcene chemotype...
April 15, 2018: Food Chemistry
https://www.readbyqxmd.com/read/29287355/exploring-a-volatomic-based-strategy-for-a-fingerprinting-approach-of-vaccinium-padifolium-l-berries-at-different-ripening-stages
#10
Priscilla Porto-Figueira, José A Figueira, Pedro Berenguer, José S Câmara
The effect of ripening on the evolution of the volatomic pattern from endemic Vaccinium padifolium L. (Uveira) berries was investigated using headspace-solid phase microextraction (HS-SPME) followed by gas chromatography/quadrupole-mass spectrometry (GC-qMS) and multivariate statistical analysis (MVA). The most significant HS-SPME parameters, namely fibre polymer, ionic strength and extraction time, were optimized in order to improve extraction efficiency. Under optimal experimental conditions (DVB/CAR/PDMS fibre coating, 40°C, 30min extraction time and 5g of sample amount), a total of 72 volatiles of different functionalities were isolated and identified...
April 15, 2018: Food Chemistry
https://www.readbyqxmd.com/read/29285930/improving-the-sensitivity-of-solid-phase-microextraction-by-reducing-the-volume-of-off-line-elution-solvent
#11
Jianqiao Xu, Xiwen Liu, Qi Wang, Shuyao Huang, Li Yin, Jing Xu, Xianguo Liu, Ruifen Jiang, Fang Zhu, Gangfeng Ouyang
Solid-phase microextraction (SPME) coupled with liquid chromatograph (LC) is widely used to detect polar and ionic organic compounds including various pharmaceuticals and endogenous bioactive compounds. In this study, a small-sized insert tube for the use in the commercial autosampler vial was designed for eluting the extracted analytes from SPME fibers for LC analysis. By using this custom-made insert tube as an alternative to the commercial insert tube, the volume of the elution solvent was reduced four fifths...
December 29, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/29280218/rapid-monitoring-of-pharmacological-volatiles-of-night-flowering-evening-primrose-according-to-flower-opening-or-closing-by-fast-gas-chromatography-surface-acoustic-wave-sensor-electronic-znose
#12
Se Yeon Oh
INTRODUCTION: Aroma is important in night-flowering species, as visually they can not be observed well. Thus, the analysis of the volatiles of evening-primrose is of great interest in biological fields and therapy. Furthermore, the analysis of volatiles demands rapid and simple procedure, because volatiles decompose. OBJECTIVE: The aim of this study is to show the rapid monitoring of the volatiles of evening-primrose according to the flowering or closing by fast gas chromatography/surface acoustic wave GC/SAW...
December 26, 2017: Phytochemical Analysis: PCA
https://www.readbyqxmd.com/read/29280145/comparative-analysis-of-volatile-compound-profiles-of-propolis-from-different-provenances
#13
Lina G Mohtar, Sergio A Rodríguez, Mónica A Nazareno
BACKGROUND: Propolis is a complex mixture that honey bees produce from the exudates of various plants and presents many medicinal properties. Its chemical compositions varies according to the phytogeography characteristics of each region, among others. The aim of this study was to identify and characterize the volatile organic compounds (VOCs) present in Venezuelan propolis and compare with reference samples such as Brazilian and Argentinian ones. RESULTS: A total of 90 VOCs were identified in a series of propolis samples using both Solid-Phase Microextraction (SPME) and Dynamic Headspace (DHS), both coupled to C-EI-MS...
December 27, 2017: Journal of the Science of Food and Agriculture
https://www.readbyqxmd.com/read/29278017/in-vitro-human-colonic-fermentation-of-indigestible-fraction-isolated-from-lunch-menus-impact-on-the-gut-metabolites-and-antioxidant-capacity
#14
Victor Manuel Zamora-Gasga, Alicia Paulina Cárdenas-Castro, Efigenia Montalvo-González, María Guadalupe Flavia Loarca-Piña, Vázquez-Landaverde Pedro Alberto, Juscelino Tovar, Sonia Guadalupe Sáyago-Ayerdi
The indigestible fraction (IF) isolated from three lunch menus: Modified Mexican Lunch (MM-L), Traditional Mexican Lunch (TM-L) and Alternative Mexican Lunch (AM-L), was studied in terms of antioxidant capacity (AOX) and metabolites produced through fermentation by human intestinal microbiota. IFs were isolated after withstanding in vitro gastrointestinal digestion and total soluble polyphenols (TSP), condensed tannins (CT), hydrolysable polyphenols (HP) and AOX (DPPH, FRAP) were evaluated. AOX, pH and bacterial metabolites profile changes were also monitored during in vitro colonic fermentation...
December 26, 2017: International Journal of Food Sciences and Nutrition
https://www.readbyqxmd.com/read/29273907/comparison-of-the-atmospheric-and-reduced-pressure-hs-spme-strategies-for-analysis-of-residual-solvents-in-commercial-antibiotics-using-a-steel-fiber-coated-with-a-multiwalled-carbon-nanotube-polyaniline-nanocomposite
#15
Ali Reza Ghiasvand, Kolsoum Nouriasl, Fatemeh Yazdankhah
A low-cost, sensitive and reliable reduced-pressure headspace solid-phase microextraction (HS-SPME) setup was developed and evaluated for direct extraction of residual solvents in commercial antibiotics, followed by determination by gas chromatography with flame ionization detection (GC-FID). A stainless steel narrow wire was made porous and adhesive by platinization by a modified electrophoretic deposition method and coated with a polyaniline/multiwalled carbon nanotube nanocomposite. All experimental variables affecting the extraction efficiency were investigated for both atmospheric-pressure and reduced-pressure conditions...
December 22, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/29261195/electrophoretic-deposition-of-ordered-mesoporous-carbon-nitride-on-a-stainless-steel-wire-as-a-high-performance-solid-phase-microextraction-coating
#16
M Ghaemmaghami, Y Yamini, H Amanzadeh, B Hosseini Monjezi
An electrophoretic deposition approach was developed to fabricate a robust ordered mesoporous carbon nitride (MCN) coating for solid-phase microextraction. The large surface area, uniform pore diameter, in-built N-rich functional groups, and electron delocalization properties of MCN make it a promising adsorbent for SPME by π-π, hydrogen bonding and hydrophobic interactions between analytes and MCN.
December 20, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/29250799/comparison-of-sensory-and-chemical-evaluation-of-lager-beer-aroma-by-gc-and-gc-ms
#17
Miha Ocvirk, Nataša Kočar Mlinarič, Iztok J Košir
BACKGROUND: Although beer evaluation runs with sensory experts, we cannot neglect the influence of the human factor and subjectivity. This problem could be solved with chemical analysis of the volatile part of beer aroma from which we can build a data bank for construction a model to classify samples comparable to sensory assessment. RESULTS: 22 batches of the same beer brand were assessed for sensory and chemically described with the contents of alcohols and esters (9),hop essential oils compounds (15) by GC and other aroma volatiles (33), analysed by head space SPME-GC/MS...
December 18, 2017: Journal of the Science of Food and Agriculture
https://www.readbyqxmd.com/read/29247980/influence-of-alcohol-containing-and-alcohol-free-cosmetics-on-faee-concentrations-in-hair-a-performance-evaluation-of-ethyl-palmitate-as-sole-marker-versus-the-sum-of-four-faees
#18
C Dumitrascu, R Paul, R Kingston, Rachel Williams
Fatty acid ethyl esters (FAEE) are direct metabolites of ethanol and have been shown to be suitable markers for the evaluation of alcohol consumption. Previous research has suggested that the regular use of alcohol containing cosmetic products can influence the concentration of FAEE detected in hair. In this study we investigated the influence of alcohol containing and alcohol free hair cosmetics (hairspray and waxes) on the FAEE concentrations in hair. The effect of cosmetic treatment was measured against the impact on ethyl palmitate in isolation as compared to the sum of four esters...
December 11, 2017: Forensic Science International
https://www.readbyqxmd.com/read/29247961/comprehensive-quality-evaluation-of-medical-cannabis-sativa-l-inflorescence-and-macerated-oils-based-on-hs-spme-coupled-to-gc-ms-and-lc-hrms-q-exactive-orbitrap%C3%A2-approach
#19
Lorenzo Calvi, Daniela Pentimalli, Sara Panseri, Luca Giupponi, Fabrizio Gelmini, Giangiacomo Beretta, Davide Vitali, Massimo Bruno, Emanuela Zilio, Radmila Pavlovic, Annamaria Giorgi
There are at least 554 identified compounds in C. sativa L., among them 113 phytocannabinoids and 120 terpenes. Phytocomplex composition differences between the pharmaceutical properties of different medical cannabis chemotype have been attributed to strict interactions, defined as 'entourage effect', between cannabinoids and terpenes as a result of synergic action. The chemical complexity of its bioactive constituents highlight the need for standardised and well-defined analytical approaches able to characterise the plant chemotype, the herbal drug quality as well as to monitor the quality of pharmaceutical cannabis extracts and preparations...
December 13, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/29238032/influence-of-fruit-ripening-on-color-organic-acid-contents-capsaicinoids-aroma-compounds-and-antioxidant-capacity-of-shimatogarashi-capsicum-frutescens
#20
Manikharda Manikharda, Makoto Takahashi, Mika Arakaki, Kaoru Yonamine, Fumio Hashimoto, Kensaku Takara, Koji Wada
Shimatogarashi (Capsicum frutescens) is a typical chili pepper domesticated in southern Japan. Important traits of Shimatogarashi peppers, such as color; proportion of organic acids, capsaicinoids, and aromatic compounds; and antioxidant activity in three stages of maturity (green (immature), orange (turning), and red (mature) stages) were characterized. The results indicated that the concentration of organic acids, including ascorbic, citric, and malic acid, increased during ripening. In addition, the amount of capsaicinoids, which are responsible for the pungent taste of chili peppers, increased as the fruit matured to the orange and red stages...
December 14, 2017: Journal of Oleo Science
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