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Isabel Clemente, Margarita Aznar, Jesús Salafranca, Cristina Nerín
One critical challenge when developing a new antimicrobial packaging material is to demonstrate the mode of action of the antimicrobials incorporated into the packaging. For this task, several analytical techniques as well as microbiology are required. In this work, the antimicrobial properties of benzyl isothiocyanate, allyl isothiocyanate and essential oils of cinnamon and oregano against several moulds and bacteria have been evaluated. Benzyl isothiocyanate showed the highest antimicrobial activity and it was selected for developing the new active packaging material...
October 25, 2016: Analytical and Bioanalytical Chemistry
Elham Aslankoohi, Beatriz Herrera-Malaver, Mohammad Naser Rezaei, Jan Steensels, Christophe M Courtin, Kevin J Verstrepen
Saccharomyces cerevisiae is routinely used yeast in food fermentations because it combines several key traits, including fermentation efficiency and production of desirable flavors. However, the dominance of S. cerevisiae in industrial fermentations limits the diversity in the aroma profiles of the end products. Hence, there is a growing interest in non-conventional yeast strains that can help generate the diversity and complexity desired in today's diversified and consumer-driven markets. Here, we selected a set of non-conventional yeast strains to examine their potential for bread fermentation...
2016: PloS One
Mingxue Wu, Gang Chen, Jiutong Ma, Ping Liu, Qiong Jia
Covalent organic frameworks (COFs) are an emerging class of porous organic frameworks with diverse promising applications. Herein, we presented the first example of cross-linked hydrazone COFs (cross-linked COFs) coating via thiol-ene click chemistry for solid phase microextraction (SPME). Strong covalent bonds and interlayer of the prepared networks ensured the adsorption capacity and durability of the novel SPME fiber. π-π conjugated structure existed because of abundant phenyl rings and -C=N groups in the cross-lined COFs...
December 1, 2016: Talanta
Wenchang Wang, Juntao Wang, Shuaihua Zhang, Penglei Cui, Chun Wang, Zhi Wang
A novel covalent organic framework, Schiff base network-1 (SNW-1), was synthesized and used as a solid-phase microextraction (SPME) fiber coating material. The SNW-1 coated SPME fiber was fabricated by a covalent chemical cross-linking between the SNW-1 nanocomposite and a silanol-functionalized stainless steel wire substrate. Scanning electron microscopy and nitrogen isothermal adsorption results indicate that the new fiber coating exhibited a porous, homogenous surface with the Brunauer-Emmett-Teller surface of 668m(2)g(-1)...
December 1, 2016: Talanta
Paramee Kumkrong, Benjaporn Thiensong, Phuong Mai Le, Garnet McRae, Anthony Windust, Suladda Deawtong, Juris Meija, Paulette Maxwell, Lu Yang, Zoltán Mester
Methods based on species specific isotope dilution were developed for the accurate and SI traceable determination of arsenobetaine (AsBet) and methylmercury (MeHg) in prawn and cuttlefish tissues by LC-MS/MS and SPME GC-ICPMS. Quantitation of AsBet and MeHg were achieved by using a (13)C-enriched AsBet spike (NRC CRM CBET-1) and an enriched spike of Me(198)Hg (NRC CRM EMMS-1), respectively, wherein analyte mass fractions in enriched spikes were determined by reverse isotope dilution using natural abundance AsBet and MeHg primary standards...
November 2, 2016: Analytica Chimica Acta
Liu Yang, Jie Zhang, Faqiong Zhao, Baizhao Zeng
In this work, a novel poly(3,4-ethylenedioxythiophene)@Au nanoparticles (PEDOT@AuNPs) hybrid coating was prepared and characterized. Firstly, the monomer 3,4-ethylenedioxythiophene was self-assembled on AuNPs, and then electropolymerization was performed on a stainless steel wire by cyclic voltammetry. The obtained PEDOT@AuNPs coating was rough and showed cauliflower-like micro-structure with thickness of ∼40μm. It displayed high thermal stability (up to 330°C) and mechanical stability and could be used for at least 160 times of solid phase microextraction (SPME) without decrease of extraction performance...
October 14, 2016: Journal of Chromatography. A
Thais M Uekane, Luca Nicolotti, Alessandra Griglione, Humberto R Bizzo, Patrizia Rubiolo, Carlo Bicchi, Maria Helena M Rocha-Leão, Claudia M Rezende
The volatile fraction of murici, bacuri and sapodilla are here studied because of their increasing interest for consumers, abundance of production in Brazil, and the general demand for new flavors and aromas. Their volatile profiles were studied by two High Concentration Capacity Headspace techniques (HCC-HS), Headspace Solid Phase Microextraction (HS-SPME) and Headspace Sorptive Extraction (HSSE), in combination with GC-MS. Murici volatile fraction mainly contains esters (38%), carboxylic acids (19%), aldehydes (11%), alcohols (14%), others (13%) and sulfur compounds; bacuri is characterized by terpenes (41%), non-terpenic alcohols (24%), esters (15%), aldehydes (6%), and others (12%); sapodilla consists of esters (33%), alcohols (27%), terpenes (18%) and others (21%)...
March 15, 2017: Food Chemistry
Han Wang, Xingyu Gao, Jun Fang
The smooth particle mesh Ewald (SPME) method is the standard method for computing the electrostatic interactions in the molecular simulations. In this work, we develop the multiple staggered mesh Ewald (MSME) method, which averages the SPME forces computed on, e.g. M, staggered meshes. We prove, from a theoretical perspective, that the MSME is as accurate as the SPME, but uses M(2) times less mesh points in a certain parameter range. In the complementary parameter range, the MSME is as accurate as the SPME with twice of the interpolation order...
October 19, 2016: Journal of Chemical Theory and Computation
M V Nair, G M Miskelly
Clandestine laboratories pose a serious health risk to first responders, investigators, decontamination companies, and the public who may be inadvertently exposed to methamphetamine and other chemicals used in its manufacture. Therefore there is an urgent need for reliable methods to detect and measure methamphetamine at such sites. The most common method for determining methamphetamine contamination at former clandestine laboratory sites is selected surface wipe sampling, followed by analysis with gas chromatography-mass spectrometry (GC-MS)...
October 3, 2016: Forensic Science International
Yung-Han Shih, Kuen-Yun Wang, Brenda T Singco, Chia-Her Lin, Hsi-Ya Huang
In this study, we first demonstrated the effect of two types of metal-organic framework-polymer (MOF-polymer) monoliths on in-tube solid-phase microextraction (IT-SPME) of sulfonamides. Sulfonamides were successfully adsorbed onto MIL-101(Cr)-polymer but were difficult to elute due to these sulfonamides could interact via Lewis acid-base interaction with the presence of Cr(III) coordinatively unsaturated metal sites (CUS). Moreover, the cage-type topology of MIL-101(Cr) that could produce multiple pathways thus complicates the desorption of the test analytes from the sorbent...
October 17, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Guozhu Zhao, Guohua Yin, Arati A Inamdar, Jing Luo, Ning Zhang, Ill Yang, Brian Buckley, Joan W Bennett
Super Storm Sandy provided an opportunity to study filamentous fungi (molds) associated with winter storm damage. We collected 36 morphologically distinct fungal isolates from flooded buildings. By combining traditional morphological and cultural characters with an analysis of ITS sequences (the fungal DNA barcode), we identified 24 fungal species that belong to 8 genera: Penicillium (12 species), Fusarium (4 species), Aspergillus (3 species), Trichoderma (2 species), and one species each of Metarhizium, Mucor, Pestalotiopsis, and Umbelopsis...
October 17, 2016: Indoor Air
Xiaowei Xiang, Bing Shang, Xiaozheng Wang, Qinhua Chen
Yohimbine is a novel compounds for treatment of erectile dysfunction derived from natural products and pharmacokinetic study is important for its further development as a new medicine. In this work, we developed a novel PEEK tube-based solid-phase microextraction (SPME)-HPLC method for analysis of yohimbine in plasma and further for pharmacokinetic study. Poly (AA-EGDMA) was synthesized inside PEEK tube as the sorbent for microextraction of yohimbine, and parameters that could influence extraction efficiency were systematically investigated...
October 14, 2016: Biomedical Chromatography: BMC
Minoo Sadri, Hossein Vatani
An ionic liquid-mediated multi-walled carbon nanotube (MWCNT)-polydimethylsiloxane (PDMS) sorbent was developed for headspace solid-phase microextraction (HS-SPME) of phenolic compounds from human urine samples. Sol-gel method was used to prepare this sorbent. For this purpose, MWCNTs were functionalized covalently and were attached chemically to the hydroxyl-terminated PDMS. Prepared fiber showed high thermal stability (over than 320°C) and good lifespan (>210 times). These good performances can be attributed to the performance of carbon nanotubes and sol-gel method...
October 12, 2016: Journal of Chromatographic Science
Zhan-Nan Yang, Shi-Qiong Luo, Jing Ma, Dan Wu, Liang Hong, Zheng-Wen Yu
GC-MS is the basis of analysis of plant volatiles. Several protocols employed for the assay have resulted in inconsistent results in the literature. We developed a GC-MS method, which were applied to analyze 25 volatiles (α-pinene, camphene, β-pinene, 2-methyl-2-pentenal, myrcene, (+)-limonene, eucalyptol, trans-2-hexenal, γ-terpinene, cis-3-hexeneyl-acetate, 1-hexanol, α-pinene oxide, cis-3-hexen-1-ol, trans-2-hexen-1-ol, decanal, linalool, acetyl-borneol, β-caryophyllene, 2-undecanone, 4-terpineol, borneol, decanol, eugenol, isophytol and phytol) of Houttuynia cordata Thunb...
September 2016: Pakistan Journal of Pharmaceutical Sciences
Thamani T Gondo, Veronica C Obuseng, Lesego C Mmualefe, Harriet Okatch
HS-SPME was optimised using blank plant sample for analysis of organochlorine pesticides (OCPs) of varying polarities in selected medicinal plants obtained from northern part of Botswana, where OCPs such as DDT and endosulfan have been historically applied to control disease carrying vectors (mosquitos and tsetse fly). The optimised SPME parameters were used to isolate analytes from root samples of five medicinal plants obtained from Maun and Kasane, Botswana. The final analytes determination was done with a gas chromatograph equipped with GC-ECD and analyte was confirmed using electron ionisation mass spectrometer (GC-MS)...
2016: Journal of Analytical Methods in Chemistry
Mustafa Kiralan, Mohamed Fawzy Ramadan
The goal of this study was to investigate the effect of heating and microwave treatment on the levels of volatile oxidation products and the stability of safflower (Carthamus tinctorius L.), sesame (Sesamum indicum) and canola (Brassica napus L.) cold-pressed oils. Cold-pressed oils were subjected to conventional heating (oven test) using air-forced oven at 60°C and microwave heating for 2 and 4 min. The changes in conjugated diene (CD) and conjugated triene (CT) values were monitored during treatments. As expected, heating generates an increase in CD and CT values...
2016: Journal of Oleo Science
Sara Armorini, James E Yeatts, Keena A E Mullen, Sharon E Mason, Elmira Mehmeti, Kevin L Anderson, Steve P Washburn, Ronald E Baynes
Thymol and carvacrol may be present in several phytoceutical products but there are no well-defined methods to measure these compounds in meat and milk from treated animals. U.S. regulatory authorities deem their presence as an adulteration of food. A rapid and sensitive HS-SPME-GC-MS/MS method was developed for the detection of thymol and carvacrol in bovine milk, plasma, liver, kidney, and fat. Inter- and intraday precision values were all less than 15.7 and 20.2% for thymol and carvacrol, respectively. The accuracy was in ranges of 69...
October 11, 2016: Journal of Agricultural and Food Chemistry
Afsoon Pajand Birjandi, Barbara Bojko, Zhibin Ning, Daniel Figeys, Janusz Pawliszyn
A new SPME method for untargeted lipidomic study of cell line cultures was proposed for the first time. In this study the feasibility to monitor changes in lipid profile after external stimuli was demonstrated and compared to the conventional Bligh & Dyer method. The human hepatocellular carcinoma (HCC) cell line was used as a model. The obtained results provided a list of up-regulated and down-regulated lipids through a comparison between control (non-stimulated) cells versus the group of cells treated with polyunsaturated fatty acid (20:5)...
September 29, 2016: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Igor Jerković, Zvonimir Marijanović, Marina Zekić, Carlo I G Tuberoso
Rare Moltkia petraea (Tratt.) Griseb. honey from Croatia was first time characterised. The spectrophotometric assays on CIE L*a*b*Cab *hab ° colour coordinates, total phenol content and antioxidant capacity (FRAP, CUPRAC, DPPH(●) and ABTS(●+) assays) determined higher honey values generally close to dark honeys ranges. Headspace solid-phase microextraction (HS-SPME) on two fibres after GC-FID and GC-MS revealed the major compounds 2-phenylacetaldehyde (12.8%; 15.6%), benzaldehyde (11.1%; 10.0%), octane (9...
October 8, 2016: Chemistry & Biodiversity
Guo-Hua Zhang, Tao Wu, Faizan A Sadiq, Huan-Yi Yang, Tong-Jie Liu, Hui Ruan, Guo-Qing He
Aroma of Chinese steamed bread (CSB) is one of the important parameters that determines the overall quality attributes and consumer acceptance. However, the aroma profile of CSB still remains poorly understood, mainly because of relying on only a single method for aroma extraction in previous studies. Therefore, the objective of this study was to determine the volatile aroma compounds of five different samples of CSB using three different aroma extraction methods, namely solid-phase microextraction (SPME), simultaneous distillation-extraction (SDE), and purge and trap (P&T)...
2016: Journal of Zhejiang University. Science. B
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