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David J S Patinha, Liliana C Tomé, Mehmet Isik, David Mecerreyes, Armando J D Silvestre, Isabel M Marrucho
Crosslinked pyrrolidinium-based poly(ionic liquids) (Pyrr-PILs) were synthesized through a fast, simple, and solventless photopolymerization scheme, and tested as solid phase microextraction (SPME) sorbents. A series of Pyrr-PILs bearing three different alkyl side chain lengths with two, eight, and fourteen carbons was prepared, characterized, and homogeneously coated on a steel wire by using a very simple procedure. The resulting coatings showed a high thermal stability, with decomposition temperatures above 350 °C, excellent film stability, and lifetime of over 100 injections...
September 18, 2017: Materials
M Fernández-Amado, M C Prieto-Blanco, P López-Mahía, S Muniategui-Lorenzo, D Prada-Rodríguez
An in-tube solid phase microextraction, coupled with high-performance liquid chromatography with diode array detection (IT-SPME-HPLC-DAD) method, has been developed for the simultaneous determination of 13 diesters (from dimethyl to dioctylphthalate plus diisobutyl, benzylbutyl, di-2-ethylhexyl, diisononyl and diisodecylphthalate) and 2 monoesters of phthalic acid (mono-butyl and mono-(2-ethylhexyl) phthalate) in particulate matter (PM10). Triethylamine at pH=3 was used as an ion-pair reagent with a double function, of regulating the chromatographic retention of the monoesters and the most hydrophilic diesters on a monolithic silica column, and of improving their extraction on a porous polymer with divinylbenzene-4-vinylpyridine capillary...
September 6, 2017: Journal of Chromatography. A
Tanja Živković Semren, Irena Brčić Karačonji, Toni Safner, Nataša Brajenović, Blanka Tariba Lovaković, Alica Pizent
Non-targeted metabolomics research of human volatile urinary metabolome can be used to identify potential biomarkers associated with the changes in metabolism related to various health disorders. To ensure reliable analysis of urinary volatile organic metabolites (VOMs) by gas chromatography-mass spectrometry (GC-MS), parameters affecting the headspace-solid phase microextraction (HS-SPME) procedure have been evaluated and optimized. The influence of incubation and extraction temperatures and times, coating fibre material and salt addition on SPME efficiency was investigated by multivariate optimization methods using reduced factorial and Doehlert matrix designs...
January 1, 2018: Talanta
Shuqin Liu, Lijun Xie, Qingkun Hu, Huangsheng Yang, Guanrui Pan, Fang Zhu, Shenghong Yang, Gangfeng Ouyang
This study presents the preparation and the characterizations of six tri-metal centered metal-organic frameworks (tM-MOFs) as solid-phase microextraction (SPME) adsorbents. Possessing different proportions of Al, Ga and In atoms in their frameworks, the tM-MOF-based SPME coatings exhibited different extraction performance towards the organic pollutants. Extraction results showed that the M4 (Al0.593Ga0.167In0.240(O2C2H4)(h2fipbb)) coating exhibited the best enrichment ability among six tM-MOFs. In addition, it showed better extraction efficiency towards the analytes than three single-metal centered MOFs coatings and a commercial polydimethylsiloxane (PDMS) coating...
September 22, 2017: Analytica Chimica Acta
Benjamin Savareear, Radoslaw Lizak, Michał Brokl, Chris Wright, Chuan Liu, Jean-Francois Focant
A method involving headspace solid-phase microextraction (HS-SPME) and comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC-TOFMS) was developed and optimised to elucidate the volatile composition of the particulate phase fraction of aerosol produced by tobacco heating products (THPs). Three SPME fiber types were studied in terms of extraction capacity and precision measurements. Divinylbenzene polydimethylsiloxane appeared as the most efficient coating for these measurements...
September 7, 2017: Journal of Chromatography. A
Xingru Hu, Chao Liu, Jiansheng Li, Rui Luo, Hui Jiang, Xiuyun Sun, Jinyou Shen, Weiqing Han, Lianjun Wang
In this study, a novel hollow mesoporous carbon spheres-based fiber (HMCSs-F) was fabricated to immobilize HMCSs onto a stainless steel wire for solid-phase microextraction (SPME). Characterization results showed that the HMCSs-F possessed a large specific surface area, high porosity and uniform pore size. To demonstrate the extraction performance, a series of polycyclic aromatic hydrocarbons (PAHs) was chosen as target analytes. The experimental parameters including extraction and desorption conditions were optimized...
September 6, 2017: Journal of Chromatography. A
Anupam Giri, Zuzana Zelinkova, Thomas Wenzl
For the implementation of EU legislation related to smoke flavourings used or intended for use in or on foods (Regulation (EC) No 2065/2003) a method based on solid phase micro extraction (SPME) GC/MS was developed for the chracterisation of liquid smoke products. A statistically based experimental design (DoE) was used for method optimization. The best general conditions to quantitatively analyze the liquid smoke compounds were obtained with a polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber, 60°C extraction temperature, 30 min of extraction time, 250°C desorption temperature, 180 sec of desorption time, agitation time of 15 sec and agitation speed of 250 rpm...
September 8, 2017: Food Additives & Contaminants. Part A, Chemistry, Analysis, Control, Exposure & Risk Assessment
Keaton S Nahan, Noe Alvarez, Vesselin Shanov, Anne Vonderheide
Mass spectrometry continues to tackle many complicated tasks, and ongoing research seeks to simplify its instrumentation as well as sampling. The desorption electrospray ionization (DESI) source was the first ambient ionization source to function without extensive gas requirements and chromatography. Electrospray techniques generally have low efficiency for ionization of nonpolar analytes and some researchers have resorted to methods such as direct analysis in real time (DART) or desorption atmospheric pressure chemical ionization (DAPCI) for their analysis...
September 7, 2017: Journal of the American Society for Mass Spectrometry
Elena Bancalari, Maria Luisa Savo Sardaro, Alessia Levante, Angela Marseglia, Augusta Caligiani, Camilla Lazzi, Erasmo Neviani, Monica Gatti
Lactic acid bacteria are commonly used in dairy industries to acidify milk and to enhance the flavour of the end products thanks to their metabolisms. The formation routes of aroma compounds mainly rely on the specific ability of different species and strains to convert precursors derived from carbohydrate and amino acids catabolism. It is well known that the strains largely involved in the aroma formation of the very appreciated Italian long ripened cheeses belong to the Lactobacillus casei group and origin from raw milk...
October 2017: Food Research International
C Besada, G Sanchez, R Gil, A Granell, A Salvador
In recent years, the advantageous traits of three new loquat cultivars have drawn the attention of breeders and growers. All three have spontaneously arisen from the 'Algerie' cultivar: the new 'Xirlero' cultivar is a bud mutant of 'Algerie', while 'Amadeo' and 'Raúl' arose as chance seedlings. Following a non-targeted approach based on HS-SPME-GC-MS, the volatile compounds profile of the fruits from the new cultivars were obtained and compared to the original 'Algerie' cultivar. Carboxylic acids clearly dominated the volatile profile of all the loquat cultivars, but esters, aldehydes, ketones and alcohols were also predominant compounds...
October 2017: Food Research International
Fei He, YanPing L Qian, Michael C Qian
Flavor stability of hard tea beverage was investigated over eight weeks of storage. The volatile compounds were analyzed using solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) and two-dimensional GC-MS. Quantitative analysis showed that the concentrations of linalool, citronellol, geranial, neral, geraniol, and nerol decreased dramatically during storage, whereas α-terpineol showed an increasing trend during storage. Heart-cut two-dimensional GC-MS (2D-GC-MS) chirality analysis showed that (R)-(+)-limonene, (R)-(-)-linalool, (S)-(-)-α-terpineol and (S)-(-)-4-terpineol dominated in the fresh hard tea samples, however, the configuration changed during storage for the terpene alcohols...
January 15, 2018: Food Chemistry
Antonio Higinio Sánchez, Antonio López-López, Amparo Cortés-Delgado, Víctor Manuel Beato, Eduardo Medina, Antonio de Castro, Alfredo Montaño
The volatile profile of Spanish-style green table olives after fermentation and the changes in volatile compounds that occurred as a result of the post-fermentation and subsequent packing stage were explored by solid phase micro-extraction (SPME) and gas chromatography coupled to mass spectrometry (GC-MS). Three olive cultivars (Manzanilla, Gordal, and Hojiblanca) were processed and olive samples were taken at three different times throughout the elaboration: after fermentation, after post-fermentation, and after packing...
January 15, 2018: Food Chemistry
Marine Gammacurta, Georgia Lytra, Axel Marchal, Stéphanie Marchand, Jean Christophe Barbe, Virginie Moine, Gilles de Revel
This research investigated the influence of lactic acid bacteria (LAB) strains on ester levels in Bordeaux red wines. These wines were made in five Bordeaux areas in two vintages, using three yeast strains. Malolactic fermentation (MLF) was carried out using industrial starters or indigenous strains, each in triplicate. Ester concentrations were determined by liquid-liquid-extraction- or HS-SPME-GC/MS at various stages in the winemaking process. The levels of most compounds were slightly impacted by LAB, depending on grape variety...
January 15, 2018: Food Chemistry
Omprakash Nacham, Kevin D Clark, Marcelino Varona, Jared L Anderson
In this study, a solid-phase microextraction (SPME) method was developed for the purification of messenger RNA (mRNA) from complex biological samples using a real-time reverse transcription quantitative polymerase chain reaction (RT-qPCR) assay for quantification. The chemical composition of the polymeric ionic liquid (PIL) and a poly acrylate (PA) SPME sorbent coating was optimized to enhance the extraction performance. Of the studied SPME sorbent coatings, the PIL containing carboxylic acid moieties in the monomer and halide-based anions extracted the highest amount of mRNA from aqueous solutions, whereas the native PA fiber showed the lowest extraction efficiency...
September 5, 2017: Analytical Chemistry
Gaalebalwe Ntlhokwe, Magdalena Muller, Elizabeth Joubert, Andreas G J Tredoux, André de Villiers
The volatile composition of honeybush (Cyclopia) species was studied by comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC-TOF-MS). Headspace-solid phase micro-extraction (HS-SPME) was used to extract the volatile compounds from tea infusions prepared from the three species C. genistoides, C. maculata and C. subternata. A total of 287 compounds were identified, 101 of which were confirmed using reference standards, while the remainder were tentatively identified using mass spectral and retention index (RI) data...
August 24, 2017: Journal of Chromatography. A
Xuan Wang, Nengsheng Ye
In the field of analytical chemistry, sample preparation and chromatographic separation are two core procedures. The means by which to improve the sensitivity, selectivity and detection limit of a method have become a topic of great interest. Recently, porous organic frameworks, such as metal-organic frameworks (MOFs) and covalent organic frameworks (COFs), have been widely used in this research area because of their special features, and different methods have been developed. This review summarizes the applications of MOFs and COFs in sample preparation and chromatographic stationary phases...
September 4, 2017: Electrophoresis
Yi-Tien Chiu, Hsin-Chun Chen, Chen Chang
Oncidium is an important ornamental crop worldwide, and in recent years, the characteristics of the flower aroma have become a concern for breeders. This study used headspace solid-phase microextraction (HS-SPME) and gas chromatography/mass spectrometry (GC-MS) analysis of the volatile compounds to study the aroma characteristics of Onc. Rosy Sunset. A total of 45 compounds were identified, with the major compound being linalool. Onc. Rosy Sunset had the highest odor concentration from 10:00 to 12:00 and lowest from 20:00 to 24:00...
September 4, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Paulo Cardoso, Magda Santos, Rosa Freitas, Sílvia M Rocha, Etelvina Figueira
The volatile metabolome of Rhizobium sp. strain E20-8 exposed to three concentrations of cadmium (2.5, 5.0 and 7.5 μM) was screened using comprehensive two-dimensional gas chromatography coupled to time of flight mass spectrometry (GC × GC-ToFMS), combined with headspace solid phase microextraction (HS-SPME). Cd exposure induced a global increase in the concentration of volatile organic compounds (VOCs) both intra and extracellularly. Peak areas of several linear alkanes, ketones, aldehydes, alcohols, terpenic and volatile sulfur compounds, and one ester (ethyl acetate), were especially increased when compared with the control condition (no Cd)...
August 30, 2017: Environmental Pollution
I Domínguez, F J Arrebola, R Romero-González, A Nieto-García, J L Martínez Vidal, A Garrido Frenich
With the aim of monitoring water quality according to the regulations established by the European Union it would be necessary to implement analytical methodologies capable of simultaneously determining a broad range of organic pollutants at ultra-trace levels, allowing for increased sample throughput. In addition, the high number of samples to be analyzed requires a particular focus on setting up fully automated analytical methodologies. In view of that, this study is aimed at the development of a complete automated procedure for the ultra-trace determination of certain pesticides, polycyclic aromatic hydrocarbons (PAHs), brominated diphenyl ethers (BDEs) and polychlorinated biphenyls (PCBs) in surface waters...
August 24, 2017: Journal of Chromatography. A
Nan Chen, Yu Bai, Yong-Liang Fan, Tong-Xian Liu
Insect cuticular hydrocarbons (CHCs) play critical roles in reducing water loss and chemical communication. Species-specific CHC profiles have been used increasingly as an excellent character for species classification. However, considerably less is known about their potential for population delimitation within species. The aims of this study were to develop a solid-phase microextraction (SPME)-based CHC collection method and to investigate whether CHC profiles could serve as potential chemotaxonomic tools for intraspecific delimitation in Acyrthosiphon pisum...
2017: PloS One
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