Solid-phase Microextraction In Combination Research Articles

Inhibitory Abilities of Bacillus Isolates and Their Culture Filtrates against the Gray Mold Caused by Botrytis cinerea on Postharvest Fruit.

Botrytis cinerea, a major phytopathogenic fungus, has been reported to infect more than 200 crop species worldwide, and it causes massive losses in yield. The aim of this study was to evaluate the inhibitory abilities and effects of Bacillus amyloliquefaciens RS-25, Bacillus licheniformis MG-4, Bacillus subtilis Z-14, and Bacillus subtilis Pnf-4 and their culture filtrates and extracts against the gray mold caused by B. cinerea on postharvest tomato, strawberry, and grapefruit. The results revealed that the cells of Z-14, culture filtrate of RS-25, and cells of Z-14 showed the strongest biocontrol activity against the gray mold on the strawberry, grape, and tomato fruit, respectively. All the strains produced volatile organic compounds (VOCs), and the VOCs of Pnf-4 displayed the highest inhibition values. Based on headspace solid-phase microextraction in combination with gas chromatography-mass spectrometry, esters accounted for the largest percentage of the VOCs produced by RS-25, MG-4, Z-14, and Pnf-4 (36.80%, 29.58%, 30.78%, and 36.26%, respectively). All the strains showed potent cellulase and protease activities, but no chitinase activity. RS-25, Z-14, and MG-4, but not Pnf-4, grew on chrome azurol S agar, and an orange halo was formed around the colonies. All the strains showed biofilm formation, fruit colonization, and lipopeptide production, which may be the main modes of action of the antagonists against B. cinerea on the fruit. This study provides the basis for developing natural biocontrol agents against the gray mold caused by B. cinerea on postharvest fruit.

Interrelation of Volatile Organic Compounds and Sensory Properties of Alternative and Torrefied Wood Pellets

The increasing demand for wood pellets on the market, which is caused by their excellent combustion properties, inspires the production as well as the utilization of alternative biomass pellets as fuel. However, the emission of volatile organic compounds gives pellet materials a distinct odor or off-odor, which is directly perceived by the end user. Thus, there is an urgent need for knowledge about the emitted volatile organic compounds and their potential formation pathways as well as their contributions to odor properties of the pellets. In this study, pellets made of biomass energy crops (i.e., straw or miscanthus), byproducts from the food industry (i.e., rapeseed, grapevine, or DDGS (dried distillers grains with solubles from beer production)), or eucalyptus, as well as torrefied pinewood and torrefied sprucewood were investigated with respect to the emitted volatile compounds and their possible impact on the pellet odor. Headspace solid-phase microextraction in combination with gas chromatography–mass spectrometry was used to enrich, separate, and identify the compounds. Techniques used in sensory science were applied to obtain information about the odor properties of the samples. A total of 59 volatile compounds (acids, aldehydes and ketones, alcohols, terpenes, heterocyclic compounds, and phenolic compounds) were identified with different compound ratios in the investigated materials. The use of multivariate statistical data analysis provided deep insight into product–compound interrelation. For pellets produced from bioenergy crops, as well as from byproducts from the food industry, the sensory properties of the pellets reflected the odor properties of the raw material. With respect to the volatiles from torrefied pellets, those volatiles that are formed during the torrefaction procedure dominate the odor of the torrefied pellets covering the genuine odor of the utilized wood. The results of this work serve as a substantiated basis for future production of pellets from alternative raw materials.

Zwitterionic polymeric ionic liquid-based sorbent coatings in solid phase microextraction for the determination of short chain free fatty acids

Five different zwitterionic sorbent coatings based on polymeric ionic liquids (PILs) were developed by the on fiber UV co-polymerization of the zwitterionic monomers 1-vinyl-3-(alkylsulfonate)imidazolium or 1-vinyl-3-(alkylcarboxylate)imidazolium and different dicationic ionic liquid (IL) crosslinkers. The developed sorbent coatings were applied in headspace solid-phase microextraction in combination with gas chromatography-mass spectrometry for the determination of short chain free fatty acids in wine. The sorbent coatings were found to extract these analytes via a non-competitive extraction mechanism. The methodology was optimized for the two best zwitterionic PIL coatings and compared to the commercially-available carboxen/polydimethylsiloxane (CAR/PDMS) and polyacrylate (PA) fibers. The sorbent coating based on the 1-vinyl-3-(propanesulfonate)imidazolium IL (Fiber 1) was more sensitive than PA while providing similar limits of detection to CAR/PDMS for the determination of analytes in a diluted synthetic wine sample. At the same time, Fiber 1 required lower extraction times (only 20 min versus 60 min for CAR/PDMS and 40 min for PA), exhibited higher reproducibility (with relative standard deviation lower than 8.9% for a spiked level of 7 µM) and was more tolerant to ethanol present within the sample. The zwitterionic PILs were also applied for the analysis of red wine, and the results were in agreement with those obtained for CAR/PDMS. The analytes were detected and quantified in the concentration range from 0.18 ± 0.03 mg L−1 to 4.8 ± 0.9 mg L−1, depending on the analyte and fiber.

New Poly(Ionic Liquid) Based Fiber for Determination of Oxytetracycline in Milk Samples by Application of SPME-CE Technique.

In this work, a procedure using solid phase microextraction in combination with capillary electrophoresis was developed for the determination of oxytetracycline in milk samples. The method involves the synthesis of poly(1-allyl-3-methyl imidazolium) chloride film on a stainless-steel bar via electropolymerization and its use as an adsorbent for oxytetracycline (OT) by an ionic exchange mechanism. The coated fiber is then immersed in milk samples for retention of oxytetracycline residues, followed by elution, drying, and reconstitution before analysis with capillary electrophoresis. The proposed method achieves a limit of detection of 70 µg L−1 with adequate precision and uncertainty, making this methodology appropriate for the determination of OT in milk samples. The method was applied to the pre-concentration and quantification of oxytetracycline in ten commercial milk samples. Two tested samples were positive for the presence of oxytetracycline but the concentration was below the maximum residue limit according to the international normative standard. The proposed methodology was evaluated according to the Eco-Scale approach, and the total score of 51 indicated that the methodology proposed is both green and acceptable despite the multi-stage character. SPME-CE methodology allows us to perform the sample pre-treatment and determination of OT in an effective and greener way, decreasing the number of steps during the analysis and the generation of waste.

A volatilomics approach for off-line discrimination of minced beef and pork meat and their admixture using HS-SPME GC/MS in tandem with multivariate data analysis

Beef, pork and mixed (70% beef and 30% pork) minced meat samples were obtained from a meat processing plant in Athens during a two-year survey and analyzed both microbiologically and by headspace solid-phase microextraction in combination with gas chromatography-mass spectrometry (HS-SPME/GC–MS). A validated method for the discrimination of minced meat was developed based on the volatile fingerprints. Unsupervised (PCA) and supervised (PLS-DA) multivariate statistical methods were applied to visualize, group and classify the samples. The data-set was divided 70% for model calibration and 30% for model prediction. During model calibration 99, 100 and 100% of the samples were correctly classified as beef, pork and mixed meat samples, respectively, while for model prediction the respective percentages were 100, 100 and 95% respectively. In both datasets, the overall correct classification rate amounted to 99% on average. Among the volatile compounds identified, heptanal, octanal, butanol, pentanol, hexanol, octanol, 1-penten-3-ol, 2-octen-1-ol, 3-hydroxy-2-butanone, 2-butanone and 2-heptanone were positively correlated with beef samples. Furthermore, pentanal, hexanal, decanal, nonanal, benzaldehyde, trans-2-hexenal, trans-2-heptenal, trans-2-octenal and 1-octen-3-one were positively correlated with pork. Lastly, the alcohols, 2-butanol and 1-octen-3-ol showed positive correlation with mixed samples. The results indicated that the volatilomics approach employed in this study could be used as an alternative method for robust and reliable discrimination and classification of meat samples in an off-line mode.

Identification of the malodour source in a complex office environment using solid-phase microextraction and gas chromatography

Permanent or recurring malodours invading office rooms have not only detrimental effects on the staff productivity but also on their health directly or through the stress mechanisms. The necessary identification and subsequent neutralisation of the malodour source is complicated by the fact that various malodour sources produce overlapping sets of volatile organic compounds (VOCs). In this contribution we present a combination of solid phase microextraction coupled with gas chromatography with mass detection (SPME/GC-MS) as a useful method for identification of VOCs in a case study of malodour occurrence in office environment.

Identification of the malodour source in a complex office environment using solid-phase microextraction and gas chromatography

Permanent or recurring malodours invading office rooms have not only detrimental effects on the staff productivity but also on their health directly or through the stress mechanisms. The necessary identification and subsequent neutralisation of the malodour source is complicated by the fact that various malodour sources produce overlapping sets of volatile organic compounds (VOCs). In this contribution we present a combination of solid phase microextraction coupled with gas chromatography with mass detection (SPME/GC-MS) as a useful method for identification of VOCs in a case study of malodour occurrence in office environment.

Solid phase microextraction and gas chromatography coupled to magnetic sector high resolution mass spectrometry for the ultra-trace determination of contaminants in surface water

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. The proposed method is based on an on-line combination of solid phase microextraction (SPME) and gas chromatography coupled to double-focusing magnetic sector high resolution mass spectrometry (GC–HRMS). SPME as well as GC–HRMS conditions were optimized to achieve maximum extraction efficiency and sensitivity, which was reinforced by using multiple ion detection (MID) as acquisition mode. Using only 19mL of water and with minimum sample manipulation, the method allowed for the determination of 53 compounds exhibiting good linearity (R2>0.99), recoveries between 84 and 118% and relative standard deviation (RSD) values <20% for intra-day and inter-day precision. In addition, the method provides quantification limits (LOQs) between 0.1–50ngL−1, lower than the Environmental Quality Standards (EQS) fixed by Directive 2013/39/EC. Finally, the method was successfully applied to determine target contaminants in Almería surface water compartments, detecting dioxin-like PCBs, BDEs and some pesticides.

Идентификация и определение органических загрязнителей в воздухе города Астана с использованием твердофазной микроэкстракции

Solid-phase microextraction in combination with gas chromatography and mass-spectrometry (GC-MS) was used for determination of benzene, toluene, ethylbenzene and o-xylene (BTEX), polycyclic aromatic hydrocarbons (PAH), and for identification of volatile organic compounds (VOCs) in ambient air of the city of Astana, Kazakhstan. The screening of the samples showed the presence of mono- and polycyclic aromatic hydrocarbons, alkanes, alkenes, phenols, and benzaldehydes. The concentrations of naphthalene were 5-7 times higher than the permissible value, it was detected in all studied air samples. Average concentration of naphthalene was 18.4 μg/m3, acenaphthylene – 0.54 μg/m3, acenaphthene – 1.63 μg/m3, fluorene – 0.79 μg/m3, anthracene – 3.27 μg/m3, phenanthrene – 0.22 μg/m3, fluorantene – 0.74 μg/m3, pyrene – 0.73 μg/m3. Average concentrations of BTEX in the studied samples were 31.1, 84.9, 10.8 and 11.6 μg/m3, respectively. Based on the statistical analysis of the concentrations of BTEX and PAH, the main source of city air pollution with them was assumed to be vehicle emissions.

Identification of volatile organic compounds extracted by headspace solid-phase microextraction in specialty beers produced in Brazil

Beer is a very complex mixture, being an alcoholic beverage obtained by fermentation processes. The consumption and production of specialty beers in Brazil have increased in the past years; however, most Brazilian brewers still depend on imported commercial starter yeast strains and raw materials. Our data also indicate that volatile profile of Brazilian beers is more influenced by raw materials. The analysis of volatile compounds in beer is important for its quality control, and the presence of aromatic substances is related to the beverage acceptance and quality. In this study, headspace solid phase microextraction in combination with gas chromatography coupled to mass spectrometric detection was used for the identification of the volatile organic compounds in 30 samples of Brazilian Pilsen and ale beers. Ninety-nine volatile compounds were identified and grouped into ketones, terpenes, esters, higher alcohols, aldehydes, fatty acids, hydrocarbon and other minority compounds. Analysis of the principal components showed that the majority of specialty beers have similar chemical characteristics, their volatile profile being characterized mainly by esters and higher alcohols. Additional studies are necessary to better characterize Brazilian specialty beers; however, our results open perspectives for future research of possible indicators and markers that may serve for the purposes of certification, as well as quality control of the beverage. Copyright © 2017 The Institute of Brewing & Distilling

Characterization and geographical discrimination of saffron from Greece, Spain, Iran, and Morocco based on volatile and bioactivity markers, using chemometrics

In the present study saffron samples from Greece, Spain, Iran, and Morocco, collected during harvesting years 2005–2014, were characterized and classified according to geographical origin using volatile compounds and selected bioactivity parameters. The volatile compounds of saffron were semi-quantified using headspace solid-phase microextraction in combination with gas chromatography/mass spectrometry. Bioactivity parameters such as total phenolic content (TPC), radical scavenging activity (%RSA), and ferric reducing antioxidant power (FRAP) were determined using spectrophotometric assays. Results showed that significant variations (P < 0.05) in the volatile content, TPC, and antioxidant activity were observed according to geographical origin of saffron. Certain volatile compounds and bioactivity parameters were also affected by harvesting year (P < 0.05). Finally, strong positive Pearson’s correlations were obtained for TPC and %RSA (r = 0.90), TPC and FRAP (r = 0.90), highlighting that the methanolic fraction of saffron is rich in phytochemicals, contributing thus, to its overall antioxidant properties. The application of LDA to above combined parameters determined, enabled the correct geographical discrimination of saffron, resulting in a correct prediction rate of 95.5%. The use of a larger number of saffron samples will further validate present results.

Coupling solid-phase microextractions and surface-enhanced Raman scattering: towards a point-of-need tool for hepatic cancer screening

A method for rapid, highly portable immunoassays at low limits of detection has been developed by combining solid-phase microextraction membranes, gold nanoparticle labels, and surface-enhanced Raman scattering.

Profiling Volatile Natural Compounds from Flowers, Leaves and Stems of Marrubium anisodon Using Headspace Solid Phase Microextraction in Combination with Gas Chromatographic Mass Spectrometric Determination

The present study describes the potential capabilities of an efficient extraction technique, namely headspace solid-phase microextraction (HS-SPME) to isolate the volatile fractions from the flowers, leaves and stems of Marrubium anisodon in combination with the analysis by GC and GC-MS. By means of the HS-SPME method, 24, 16 and 24 components were characterized in the corresponding profiles, representing 89.6%, 97.4% and 93.6% of the total compositions, respectively. Limonene was the most abundant natural compound in all the volatile profiles. It was also observed that in all of the volatiles, monoterpene hydrocarbons constituted the main components while the next most common group was due to sesquiterpene hydrocarbons for volatile parts of flowers and leaves. However, in that of stems, oxygenated monoterpenes had the second rank from frequency point of view.

Identification of volatile compounds in codfish (Gadus) by a combination of two extraction Methods coupled with GC-MS analysis

Codfish is a kind of abyssal fish species with a great value in food industry. However, the flavor of codfish, especially the unpleasant odor, has caused serious problems in its processing. To accurately identify the volatile compounds in codfish, a combination of solid phase micro-extraction (SPME) method and simultaneous distillation extraction (SDE) method was used to extract the volatiles. Gas chromatography-mass spectrometry (GC-MS) along with Kovats indices (KI) and authentic standard compounds were used to identify the volatiles. The results showed that a total of 86 volatile compounds were identified in codfish, of them 24 were extracted by SDE, 69 compounds by SPME, and 10 compounds by both SDE and SPME. Seventy volatile compounds were found to have specific odors, of them 7 typical compounds contributed significantly to the flavor of codfish. Alcohols (i.e., (E)-2-penten-1-ol and 2-octanol), esters (i.e., ethyl butyrate and methyl geranate), aldehydes (i.e., 2-dodecenal and pentadecanal) contributed the most to fresh flavor while nitrogen compounds, sulphur compounds, furans, as well as some ketones (i.e., 2-hydroxy-3-pentanone) brought unpleasant odor, such as fishy and earthy odor. It was indicated that the combination of multiple extraction methods and GC-MS analysis can enhance the accuracy of identification, and provide a reference for the further study on flavor of aquatic products.

Determinación de trihalometanos en aguas de consumo humano por microextracción en fase sólida- cromatografía de gases en Pereira, Colombia

&lt;p&gt;La desinfección del agua con cloro, genera subproductos como los trihalometanos (THM´s), a los cuales se les atribuyen propiedades cancerígenas y con un potencial efecto adverso en el sistema reproductivo. El nivel máximo permitido de THM´s en Estados Unidos es 80 µg/L, mientras que en Colombia es 200 µg/L. En este estudio un método simple, rápido y libre de solventes fue estandarizado para la determinación de THM´s en aguas para consumo humano utilizando microextracción en fase sólida con espacio de cabeza combinada con cromatografía de gases con detector de microcaptura de electrones (HS-SPME-GC-mECD) y utilizado para la cuantificación de THM´s en aguas de consumo humano. Fueron estudiados parámetros experimentales así como el tiempo de adsorción, la temperatura de adsorción y desorción, la agitación de la muestra y la adición de NaCl. Se determinaron los límites de detección y cuantificación del método y se realizó el análisis de los trihalometanos de 75 muestras de agua de la planta de tratamiento de Aguas y Aguas de la ciudad de Pereira. Las condiciones optimizadas fueron 20 min de extracción a 37 °C en presencia de 25% de NaCl y con una agitación de 200 rpm; con tiempo de desorción de 4 min a 250 °C. El rango lineal de 5-100 mg/L fue establecido con una desviación estándar relativa (%RSD) en el rango 6,1-10,1 %. Los límites de detección estuvieron en el rango 3,8-7,8 mg/L. El promedio de la concentración de THM´s fue de 55,5 mg/L el cual cumple con los límites máximos permitidos en la regulación internacional y nacional.&lt;/p&gt;

A Study on VOCs Released by Lung Cancer Cell Line Using GCMS-SPME

The gas chromatography mass spectrometry (GCMS) with combination of Solid Phase Micro-extraction (SPME) was used to study the volatile organic compounds (VOCs) which emitted by the in-vitro cultured human cells and compared with documented volatile biomarker of lung cancer. For this purpose, the lung cancer cell (A549) and non-cancerous lung cell (WI38VA13) were cultured in identical growth medium, concurrently. The VOCs in the headspace of the cell cultures and the blank growth media (reference sample) were collected directly from the culture flask using SPME for 15minutes. The results show that two different volatile metabolites were screened out between A549 cells and Wi38VA13 cells. A549 cell found to emit 2 noticeable VOC which are decane and heneicosane. While for WI38VA13, the VOCs released were 1-Heptanol and heptadecane. The acquired VOCs were compared with the previous studies. The findings in this work conclude that the specific VOC of cells can be act as their odour signature and can be used to provide non-invasively screening of lung cancer using gas array sensor devices.

Validation of SPME-GC-FID Method for Determination of Fragrance Allergens in Selected Cosmetic Products

An analytical method for simultaneous determination of 24 legislatively restricted fragrance allergens in various cosmetic products was developed and validated using a combination of solid-phase microextraction and gas chromatography with flame ionization detector. The divinylbenzene-polydimethylsiloxane (DVB-PDMS) fiber was evaluated as the best for extraction of all studied fragrance allergens at 40 °C and 20 min extraction time. All calibration curves showed good linearity in the range of 10−1 to 103 μg mL−1. Good repeatability and inter-day precision was determined for the proposed method. Detection limits for individual allergens ranged from 0.007 to 2.7 μg mL−1. The validated method was used to analyze real cosmetic samples. The obtained results indicated that not all of the analyzed cosmetic samples were labeled in accordance with European Cosmetic Directive.

Determination of Sesquiterpenes in Wines by HS-SPME Coupled with GC-MS

The sesquiterpene compounds present in red wines were characterized and quantified by Headspace Solid-Phase Microextraction in combination with Gas Chromatography–Mass Spectrometry (HS-SPME-GC-MS). Sixteen sesquiterpenes were identified, mainly hydrocarbons but also derived oxygenated compounds. Sesquiterpenes were acyclic, monocyclic, byciclic and tryciclic. Sesquiterpenes were detected in SIM (selected ion monitoring) mode using their characteristics ions. All the sesquiterpenes were identified by mass spectral data, linear retention indices (LRI), literature data and injection of standards where available. Quantitative results were obtained using the method of standard additions. The method showed an average LOD = 0.05 µg L−1 and LOQ = 0.15 µg L−1. The monocyclic sesquiterpene with the germacrene skeleton, Germacrene D and the bicyclic sesquiterpene with the muurolane skeleton, α-muurolene were present in all the wine samples analysed. Syrah wines were the samples richest in sesquiterpenes in agreement with their typical spicy and woody notes. The results evidenced the possibility to use sesquiterpenes for wine authenticity and traceability.

Cover Picture: Combination of Solid‐Phase Micro‐Extraction and Direct Analysis in Real Time‐Fourier Transform Ion Cyclotron Resonance Mass Spectrometry for Sensitive and Rapid Analysis of 15 Phthalate Plasticizers in Beverages (Chin. J. Chem. 2/2015)

Cover Picture: Combination of Solid‐Phase Micro‐Extraction and Direct Analysis in Real Time‐Fourier Transform Ion Cyclotron Resonance Mass Spectrometry for Sensitive and Rapid Analysis of 15 Phthalate Plasticizers in Beverages (Chin. J. Chem. 2/2015)

Method development by GC–ECD and HS-SPME–GC–MS for beer volatile analysis

Two methods for the extraction, identification and quantification of the highest occurrence and lowest perception threshold off-flavours in fifteen different samples of Brazilian Pilsner beers were developed. For this purpose, headspace solid phase microextraction in combination with a gas chromatography coupled to a mass spectrometric detection (HS-SPME–GC–MS) as well as headspace extraction in combination with a gas chromatography coupled to electron capture detection (HS–GC–ECD) were evaluated. The first and the second methods were used for esters and vicinal diketones analysis, respectively. All data were comprehended below the taster‘s threshold detection limit: ethyl acetate 39.48ngmL−1 (RSD mean value 4.2%), isoamyl acetate 3.88ngmL−1 (RSD mean value 3.4%), ethyl hexanoate 0.61ngmL−1 (RSD mean value 3.1%) and 2,3-butanedione 0.10ngmL−1 (RSD mean value 2.9%). The validated method demonstrated to be useful for the analysis of highest incidence beer off-flavours.