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https://www.readbyqxmd.com/read/28738664/bomb-swab-can-trace-explosive-particle-sampling-and-detection-be-improved
#1
Danny Fisher, Raya Zach, Yossef Matana, Paz Elia, Shiran Shustack, Yarden Sharon, Yehuda Zeiri
The marked increase in international terror in recent years requires the development of highly efficient methods to detect trace amounts of explosives at airports, border crossings and check points. The preferred analytical method worldwide is the ion mobility spectrometry (IMS) that is capable of detecting most explosives at the nano-gram level. Sample collection for the IMS analysis is based on swabbing of a passenger's belongings to collect possible explosive residues. The present study examines a wide range of issues related to swab-based particle collection and analysis, in the hope of gaining deeper understanding into this technique that will serve to improve the detection process...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738653/development-of-an-efficient-method-for-multi-residue-analysis-of-160-pesticides-in-herbal-plant-by-ethyl-acetate-hexane-mixture-with-direct-injection-to-gc-ms-ms
#2
Sherif M Taha, Sohair A Gadalla
A simple and efficient multi residue method was developed, for the analysis of 160 pesticides by GC-MS/MS in herbal plants. The developed method employs pesticide residue extraction by EtAC/ n. hexane (6:4) with a cleanup step using florisil/ PSA mixture. The optimized conditions have resulted in lower co-extracted matrix components than those extracted using EtAC or MeCN (QuEChERS method), according to FTIR and full scan GC/MS analyses. In addition, the developed method (EtAC/ Hexane) eliminates the evaporation step that is usually performed when using MeCN as an extraction solvent prior to the GC-MS/MS injection...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738648/matrix-interference-evaluation-employing-gc-and-lc-coupled-to-triple-quadrupole-tandem-mass-spectrometry
#3
S Uclés, A Lozano, A Sosa, P Parrilla Vázquez, A Valverde, A R Fernández-Alba
Gas and liquid chromatography coupled to triple quadrupole tandem mass spectrometry are currently the most powerful tools employed for the routine analysis of pesticide residues in food control laboratories. However, whatever the multiresidue extraction method, there will be a residual matrix effect making it difficult to identify/quantify some specific compounds in certain cases. Two main effects stand out: (i) co-elution with isobaric matrix interferents, which can be a major drawback for unequivocal identification, and therefore false negative detections, and (ii) signal suppression/enhancement, commonly called the "matrix effect", which may cause serious problems including inaccurate quantitation, low analyte detectability and increased method uncertainty...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738625/the-screening-of-organic-matter-in-mineral-and-tap-water-by-uhplc-hrms
#4
Marcos A S Ribeiro, Michael Murgu, Valquíria de Moraes Silva, Alexandra C H F Sawaya, Leomara Floriano Ribeiro, Andre Justi, Eduardo C Meurer
It is highly desirable to screen for a large variety of organic compounds in water. Ultra-high performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS) can analyse semi-polar to polar organic compounds in tap and mineral water. The use of UHPLC-HRMS is well consolidated for lipidomic, metabolomic and proteomic studies; based on the detection of a very large number of compounds of a variety of organic functions. Water analysis is usually performed by gas chromatography -mass spectrometry (GC-MS) techniques that are efficient for volatile organic compounds...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738583/application-of-headspace-and-direct-immersion-solid-phase-microextraction-in-the-analysis-of-organothiophosphates-related-to-the-chemical-weapons-convention-from-water-and-complex-matrices
#5
Marc André Althoff, Andreas Bertsch, Manfred Metzulat, Thomas M Klapötke, Konstantin L Karaghiosoff
The successful application of headspace (HS) and direct immersion (DI) solid phase microextraction (SPME) for the unambiguous identification and characterization of a series of toxic thiophosphate esters, such as Amiton (I), from aqueous phases and complex matrices (e.g. grass and foliage) has been demonstrated. A Thermo Scientific gas chromatograph (GC) - tandem mass spectrometer (MS/MS) system with a TriPlus RSH® autosampler and a SPME tool was used to investigate the effect of different parameters that influence the extraction efficiency: e...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738515/characterization-of-carbon-dioxide-concentrating-chemolithotrophic-bacterium-serratia-sp-istd04-for-production-of-biodiesel
#6
Manish Kumar, Raj Morya, Edgard Gnansounou, Christian Larroche, Indu Shekhar Thakur
Proteomics and metabolomics analysis has become a powerful tool for characterization of microbial ability for fixation of Carbon dioxide. Bacterial community of palaeoproterozoic metasediments was enriched in the shake flask culture in the presence of NaHCO3. One of the isolate showed resistance to NaHCO3 (100mM) and was identified as Serratia sp. ISTD04 by 16S rRNA sequence analysis. Carbon dioxide fixing ability of the bacterium was established by carbonic anhydrase enzyme assay along with proteomic analysis by LC-MS/MS...
July 14, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28737686/comparison-of-two-stationary-phases-for-the-determination-of-phytosterols-and-tocopherols-in-mango-and-its-by-products-by-gc-qtof-ms
#7
Ana López-Cobo, Beatriz Martín-García, Antonio Segura-Carretero, Alberto Fernández-Gutiérrez, Ana María Gómez-Caravaca
Two different gas chromatography coupled to quadrupole-time of flight mass spectrometry (GC-QTOF-MS) methodologies were carried out for the analysis of phytosterols and tocopherols in the flesh of three mango cultivars and their by-products (pulp, peel, and seed). To that end, a non-polar column ((5%-phenyl)-methylpolysiloxane (HP-5ms)) and a mid-polar column (crossbond trifluoropropylmethyl polysiloxane (RTX-200MS)) were used. The analysis time for RTX-200MS was much lower than the one obtained with HP-5ms...
July 22, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28737378/quantitative-mid-infrared-cavity-ringdown-detection-of-methyl-iodide-for-monitoring-applications
#8
Ibrahim Sadiek, Qiang Shi, Douglas Wallace, Gernot Friedrichs
Methyl iodide is a toxic halocarbon with diverse industrial and agricultural applications and is an important ocean-derived trace gas that contributes to the iodine burden of the atmosphere. Quantitative analysis of CH3I is mostly based on gas chromatography coupled with mass spectrometry or electron capture detection (GC-MS/ECD) as yet, which often limits the ability to conduct in situ high-frequency monitoring studies. This work presents an alternative detection scheme based on mid-infrared continuous wave cavity ringdown spectroscopy (mid-IR cw-CRDS)...
July 24, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28735712/analysis-of-polychlorinated-dibenzo-p-dioxins-and-dibenzofurans-in-stack-gas-emissions-by-gas-chromatography-atmospheric-pressure-chemical-ionization-triple-quadrupole-mass-spectrometry
#9
J Rivera-Austrui, K Martínez, M Ábalos, C Sales, T Portoles, J Beltran, J Sauló, B H Aristizábal, E Abad
A gas chromatography coupled to triple-quadrupole mass spectrometry (GC-(QqQ)MS/MS) including a soft-ionization through an atmospheric pressure chemical ionization (APCI) source based method was compared with the high resolution mass spectrometry (HRMS) standard reference method EN1948, for the analysis of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) in stack gas emissions. The stack emission samples were collected, both, by manual method sampling (from 6 to 8h) and by long-term sampling systems (sampling time of several weeks)...
July 12, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28735408/rapid-quantification-of-abscisic-acid-by-gc-ms-ms-for-studies-of-abiotic-stress-response
#10
Paul E Verslues
Drought and low water potential induce large increases in Abscisic Acid (ABA ) content of plant tissue. This increased ABA content is essential to regulate downstream stress resistance responses; however, the mechanisms regulating ABA accumulation are incompletely known. Thus, the ability to accurately quantify ABA at high throughput and low cost is important for plant stress research. We have combined and modified several previously published protocols to establish a rapid ABA analysis protocol using gas chromatography-tandem mass spectrometry (GC-MS/MS)...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28734978/insights-into-the-functional-properties-of-the-marneral-oxidase-cyp71a16-from-arabidopsis-thaliana
#11
Sarah Kranz-Finger, Osama Mahmoud, Esther Ricklefs, Nikolas Ditz, Patrick J Bakkes, Vlada B Urlacher
The Arabidopsis thaliana gene encoding CYP71A16 is part of the gene cluster for the biosynthesis and modification of the triterpenoid marneral. Previous investigations of A. thaliana have revealed that CYP71A16 oxidizes marneral, while it also can accept marnerol as substrate. The aim of the present study was to investigate functional properties of CYP71A16 in vitro. For this purpose, heterologous expression of a N-terminally modified version of CYP71A16 was established in Escherichia coli, which yielded up to 50mg·L(-1) recombinant enzyme...
July 19, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28734362/discrimination-of-bacteria-by-rapid-sensing-their-metabolic-volatiles-using-an-aspiration-type-ion-mobility-spectrometer-a-ims-and-gas-chromatography-mass-spectrometry-gc-ms
#12
Ileana Andreea Ratiu, Victor Bocos-Bintintan, Adrian Patrut, Victor Hugo Moll, Matthew Turner, C L Paul Thomas
The objective of our study was to investigate whether one may quickly and reliably discriminate different microorganism strains by direct monitoring of the headspace atmosphere above their cultures. Headspace samples above a series of in vitro bacterial cultures were directly interrogated using an aspiration type ion mobility spectrometer (a-IMS), which produced distinct profiles ("fingerprints") of ion currents generated simultaneously by the detectors present inside the ion mobility cell. Data processing and analysis using principal component analysis showed net differences in the responses produced by volatiles emitted by various bacterial strains...
August 22, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28733240/metabolomics-reveal-physiological-changes-in-mayfly-larvae-neocloeon-triangulifer-at-ecological-upper-thermal-limits
#13
Hsuan Chou, Wimal Pathmasiri, Jocelin Deese-Spruill, Susan Sumner, David B Buchwalter
Aquatic insects play critical roles in freshwater ecosystems and temperature is a fundamental driver of species performance and distributions. However, the physiological mechanisms that determine the thermal performance of species remain unclear. Here we used a metabolomics approach to gain insights into physiological changes associated with a short-term, sublethal thermal challenge in the mayfly Neocloeon triangulifer (Ephemeroptera: Baetidae). Larvae were subjected to a thermal ramp (from 22 to 30 °C at a rate of 1°C/h) and metabolomics analysis (both Nuclear Magnetic Resonance (NMR) Spectroscopy and Gas Chromatography coupled Time-of-Flight Mass Spectrometry (GC-TOF-MS)) indicated that processes related to energetics (sugar metabolism) and membrane stabilization primarily differentiated heat treated larvae from controls...
July 18, 2017: Journal of Insect Physiology
https://www.readbyqxmd.com/read/28733192/pharmacological-evaluation-of-phytochemicals-from-south-indian-black-turmeric-curcuma-caesia-roxb-to-target-cancer-apoptosis
#14
K S Mukunthan, R S Satyan, T N Patel
Curcuma caesia Roxb. (Black turmeric), a perennial herb of the family Zingiberaceae is indigenous to India. C. caesia is used as a spice, food preservative and coloring agent commonly in the Indian subcontinent. Functional parametric pharmacological evaluations like drug ability and toxicity profile of this endangered species is poorly documented. In our present study, among all the extracts of dried C. caesia rhizome viz- hexane, ethyl acetate, methanol and water tested for free radical scavenging capacity by total antioxidant activity (TAO) method, Hexane Rhizome Extract (HRE) wzs found to possess remarkable activity (1200mg ascorbic acid equivalent/100g)...
July 18, 2017: Journal of Ethnopharmacology
https://www.readbyqxmd.com/read/28732994/sonocatalytic-degradation-of-methylene-blue-by-a-novel-graphene-quantum-dots-anchored-cdse-nanocatalyst
#15
Saeed Sajjadi, Alireza Khataee, Mehdi Kamali
Cadmium selenide/graphene quantum dots (CdSe/GQDs) nanocatalyst with small band gap energy and a large specific surface area was produced via a facile three-step sonochemical-hydrothermal process. The features of the as-prepared CdSe, GQDs and CdSe/GQDs samples were characterized by photoluminescence spectroscopy (PL), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD), Fourier transformed infrared (FT-IR), diffuse-reflectance spectrophotometer (DRS), and Brunauer-Emmett-Teller (BET) analysis...
November 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28732946/effects-of-ultrasonic-treatment-on-the-maturation-of-zhenjiang-vinegar
#16
Zhenbin Wang, Tingting Li, Fengye Liu, Cunsheng Zhang, Haile Ma, Lin Wang, Shuai Zhao
High-quality vinegars are traditionally produced by aging them in barrels or bottles. However, these processes are very time-consuming. To accelerate of Zhenjiang vinegar maturation, the ultrasound was used to treat the steeped vinegar. Results showed that, the optimum ultrasonic power, time and ethanol addition for aging vinegar were determined to be 50W/100mL, 75min and 0.75% (V/V), respectively. Under the optimum experimental conditions, the total amino acid of fresh vinegar decreased from 1082.259mg/100mL to 871...
November 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28732860/structure-features-and-in-vitro-hypoglycemic-activities-of-polysaccharides-from-different-species-of-maidong
#17
Yajun Gong, Jie Zhang, Fei Gao, Jiewen Zhou, Zhinan Xiang, Chenggao Zhou, Luosheng Wan, Jiachun Chen
Structures and in vitro hypoglycemic activities of polysaccharides from different species of Maidong were studied. The primary structures of polysaccharides were elucidated on the basis of GC, GC-MS, infrared, NMR and periodate oxidation-Smith degradation. Liriope spicata polysaccharide (LSP), Ophiopogon japonicus polysaccharide (OJP) and Liriope muscari polysaccharide (LMP) were composed of β-fructose and α-glucose. The average molecular weights of LSP, OJP and LMP were 4742, 4925 and 4138Da with polydispersity indexes of 1...
October 1, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28732812/extracts-and-compounds-active-on-trp-ion-channels-from-waldheimia-glabra-a-ritual-medicinal-plant-from-himalaya
#18
Annamaria Giorgi, Angela Bassoli, Gigliola Borgonovo, Sara Panseri, Alessandra Manzo, Daniela Pentimalli, Aniello Schiano Moriello, Luciano De Petrocellis
BACKGROUND: Waldheimia glabra (Decne.) Regel is a wild plant from the Himalayan Mountains, commonly known as Smooth Ground Daisy. This plant is traditionally used by local populations in religious rituals (incense) or in traditional herbal medicine to treat skin diseases, headache, joint pain and fever. In literature few data are available on the investigation of this aromatic plant. PURPOSE: The present work aims at deepening knowledge about the chemical composition of W...
August 15, 2017: Phytomedicine: International Journal of Phytotherapy and Phytopharmacology
https://www.readbyqxmd.com/read/28732399/analysis-of-emerging-organic-contaminants-in-water-fish-and-suspended-particulate-matter-spm-in-the-joint-danube-survey-using-solid-phase-extraction-followed-by-uhplc-ms-ms-and-gc-ms-analysis
#19
Robert Loos, Simona Tavazzi, Giulio Mariani, Gert Suurkuusk, Bruno Paracchini, Gunther Umlauf
In the third Joint Danube Survey (JDS3), emerging organic contaminants were analysed in the dissolved water phase of samples from the Danube River and its major tributaries. Analyses were performed using solid-phase extraction (SPE) followed by ultra-high-pressure liquid chromatography triple-quadrupole mass spectrometry (UHPLC-MS-MS) and gas chromatography-mass spectrometry (GC-MS). The polar organic compounds analysed by UHPLC-MS-MS were 1H-benzotriazole, methylbenzotriazoles, carbamazepine, 10,11-dihydro-10,11-dihydroxy-carbamazepine, diclofenac, sulfamethox-azole, 2,4-D (2,4-dichlorophenoxyacetic acid), MCPA (2-methyl-4-chlorophenoxyacetic acid), metolachlor, cybutryne (irgarol), terbutryn, DEET (N,N-diethyl-m-toluamide), and several perfluoroalkyl acids (C6-C9; C8=perfluorooctanoic acid (PFOA)) and perfluorooctansulfonic acid (PFOS)...
July 17, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28731231/comparative-analysis-of-juice-volatiles-in-selected-mandarins-mandarin-relatives-and-other-citrus-genotypes
#20
Yuan Yu, Jinhe Bai, Chunxian Chen, Anne Plotto, Elizabeth A Baldwin, Frederick G Gmitter
BACKGROUND: Citrus fruit flavor is an important attribute prioritized in variety improvement. This study compared juice volatiles compositions from 13 selected citrus genotypes, including six mandarins (Citrus reticulata), three sour oranges (C. aurantium), one blood orange (C. sinensis), one lime (C. limonia), one clementine (C. clementina) and one satsuma (C. unshiu). RESULTS: Large differences were observed in volatiles compositions among the citrus genotypes...
July 21, 2017: Journal of the Science of Food and Agriculture
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