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758 KiB

Open AccessArticle

Modeling Compound Loss from Polydimethylsiloxane Passive Samplers

by Courtney L. Thomas and Danny D. Reible

Chromatography 2015, 2(4), 611-624; https://doi.org/10.3390/chromatography2040611 - 12 Oct 2015

Cited by 8 | Viewed by 5465

Abstract

Volatile losses were measured from polydimethylsiloxane (PDMS) passive samplers during determination of contaminant porewater concentrations in sediments. Volatile losses could occur between the time of retrieval and processing of the passive sampler or in intertidal environments where the passive sampler could potentially be [...] Read more.

Volatile losses were measured from polydimethylsiloxane (PDMS) passive samplers during determination of contaminant porewater concentrations in sediments. Volatile losses could occur between the time of retrieval and processing of the passive sampler or in intertidal environments where the passive sampler could potentially be exposed above the water surface at low tide. A model was developed to predict losses of absorbed compounds as a function of sorbent geometry and the Henry’s Law Coefficient and PDMS-water partition coefficient of the compound of interest. The model suggests that thin layers of PDMS typically used to minimize equilibration times in passive sampling (≤30 µm) may not provide quantitative measurement of naphthalenes or other lighter volatile compounds without special efforts to reduce losses. The results suggest that the samplers should be processed rapidly onsite or kept at low temperatures after retrieval to maximize retention of more volatile compounds or designed with thick PDMS layers. The results also suggest that less volatile compounds, including phenanthrene, and higher molecular weight polynuclear aromatic hydrocarbons (PAHs) exhibit minimal evaporative losses with typical sample processing times. Full article

(This article belongs to the Special Issue Solid Phase Micro-Extraction)

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1820 KiB

Open AccessArticle

Evaluation of Carbon Nanotubes Functionalized Polydimethylsiloxane Based Coatings for In-Tube Solid Phase Microextraction Coupled to Capillary Liquid Chromatography

by Neus Jornet-Martínez, Pascual Serra-Mora, Yolanda Moliner-Martínez, Rosa Herráez-Hernández and Pilar Campíns-Falcó

Chromatography 2015, 2(3), 515-528; https://doi.org/10.3390/chromatography2030515 - 10 Aug 2015

Cited by 11 | Viewed by 6314

Abstract

In the present work, the performance of carbon nanotubes (c-CNTs) functionalized polydimethylsiloxane (PDMS) based coatings as extractive phases for in-tube solid phase microextraction (IT-SPME) coupled to Capillary LC (CapLC) has been evaluated. Carboxylic-single walled carbon nanotubes (c-SWNTs) and carboxylic-multi walled carbon nanotubes (c-MWNTs) [...] Read more.

In the present work, the performance of carbon nanotubes (c-CNTs) functionalized polydimethylsiloxane (PDMS) based coatings as extractive phases for in-tube solid phase microextraction (IT-SPME) coupled to Capillary LC (CapLC) has been evaluated. Carboxylic-single walled carbon nanotubes (c-SWNTs) and carboxylic-multi walled carbon nanotubes (c-MWNTs) have been immobilized on the activated surface of PDMS capillary columns. The effect of different percentages of diphenyl groups in the PDMS extractive phase has also been evaluated. The extraction capability of the capillary columns has been tested for different organic pollutants, nitrogen heterocyclic compounds and polycyclic aromatic compounds (PAHs). The results indicated that the use of the c-CNTs-PDMS capillary columns improve pyriproxyfen and mainly PAH extraction. Triazines were better extracted by unmodified TRB-35 and modified c-CNTs-PDMS_TRB-5. The results showed that the extraction capability of the c-CNT capillary columns depends not only on the polarity of the analytes (as it occurs with PDMS columns) but also on the interactions that the analytes can establish with the immobilized c-CNTs on the PDMS columns. The extraction efficiency has been evaluated on the basis of the preconcentration rate that can be achieved, and, in this sense, the best c-CNTs-PDMS capillary column for each group of compounds can be proposed. Full article

(This article belongs to the Special Issue Solid Phase Micro-Extraction)

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1011 KiB

Open AccessArticle

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

by Fabrizio Cincotta, Antonella Verzera, Gianluca Tripodi and Concetta Condurso

Chromatography 2015, 2(3), 410-421; https://doi.org/10.3390/chromatography2030410 - 9 Jul 2015

Cited by 33 | Viewed by 11865

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Solid Phase Micro-Extraction)

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1727 KiB

Open AccessArticle

Automated Analysis of Oxytocin by On-Line in-Tube Solid-Phase Microextraction Coupled with Liquid Chromatography-Tandem Mass Spectrometry

by Eri Moriyama and Hiroyuki Kataoka

Chromatography 2015, 2(3), 382-391; https://doi.org/10.3390/chromatography2030382 - 30 Jun 2015

Cited by 11 | Viewed by 9585

Abstract

A simple and sensitive method for the analysis of oxytocin was developed using automated on-line in-tube solid-phase microextraction (SPME) coupled with liquid chromatography-tandem mass spectrometry (LC–MS/MS). Oxytocin was separated within 3 min on a Zorbax Eclipse XDB-C8 column, with water/methanol (10/90, v/v) as [...] Read more.

A simple and sensitive method for the analysis of oxytocin was developed using automated on-line in-tube solid-phase microextraction (SPME) coupled with liquid chromatography-tandem mass spectrometry (LC–MS/MS). Oxytocin was separated within 3 min on a Zorbax Eclipse XDB-C8 column, with water/methanol (10/90, v/v) as the mobile phase at a flow rate of 0.2 mL min⁻¹. Electrospray ionization conditions in the positive ion mode were optimized for MS/MS detection by multiple reaction monitoring. The optimum in-tube SPME conditions were 20 draw/eject cycles of 40 µL sample at a flow rate of 250 µL min⁻¹ using a Supel-Q PLOT capillary column as an extraction device. The extracted oxytocin was easily desorbed from the capillary by passage of the mobile phase, and no carryover was observed. The calibration curves for oxytocin were linear (r = 0.9981) in the range of 0−5.0 ng mL⁻¹, and the relative standard deviations at each point were below 14.7% (n = 3). The limit of detection of this method was 4.0 pg mL⁻¹, and its sensitivity was 58-fold higher than that of the direct injection method. This method was applied successfully to the analysis of oxytocin in saliva samples without any other interference peaks. Full article

(This article belongs to the Special Issue Solid Phase Micro-Extraction)

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1564 KiB

Open AccessArticle

Optimization of Biochemical Screening Methods for Volatile and Unstable Sesquiterpenoids Using HS-SPME-GC-MS

by Trine Bundgaard Andersen, Federico Cozzi and Henrik Toft Simonsen

Chromatography 2015, 2(2), 277-292; https://doi.org/10.3390/chromatography2020277 - 11 Jun 2015

Cited by 24 | Viewed by 6992

Abstract

HS-SPME-GC-MS has been suggested as a fast and robust analytical platform for the product characterization of sesquiterpene synthases. The choice of fiber and injection temperature can have a significant effect on the observed product profile, due to the chemical rearrangements that can occur [...] Read more.

HS-SPME-GC-MS has been suggested as a fast and robust analytical platform for the product characterization of sesquiterpene synthases. The choice of fiber and injection temperature can have a significant effect on the observed product profile, due to the chemical rearrangements that can occur on the fiber material. Here we present a systematic study on the effects of fiber choice and injection port temperature on the observed sesquiterpenoid profile of four sesquiterpene synthases expressed in Nicotiana benthamiana. We found that the absorbent material PDMS was much less likely to support acid-induced rearrangement of sesquiterpenoids when compared to the adsorbent materials PDMS/DVB, PDMS/CAR, and PDMS/CAR/DVB. Furthermore, utilizing an injection port temperature at 160 °C almost eliminated the inherent thermal instability of germacrene sesquiterpenoids. Thus, for fast screening of sesquiterpene synthases, the results suggest that PDMS fibers and an injection temperature of 160 °C provide a fast and reproducible HS-SPME GC-MS method when using H₂ as carrier gas. Full article

(This article belongs to the Special Issue Solid Phase Micro-Extraction)

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680 KiB

Open AccessCommunication

Studying Plant–Insect Interactions with Solid Phase Microextraction: Screening for Airborne Volatile Emissions Response of Soybeans to the Soybean Aphid, Aphis glycines Matsumura (Hemiptera: Aphididae)

by Lingshuang Cai, Jacek A. Koziel and Matthew E. O'Neal

Chromatography 2015, 2(2), 265-276; https://doi.org/10.3390/chromatography2020265 - 26 May 2015

Cited by 9 | Viewed by 6965

Abstract

Insects trigger plants to release volatile compounds that mediate the interaction with both pest and beneficial insects. Soybean aphids (Aphis glycines) induces soybean (Glycine max) leaves to produce volatiles that attract predators of the aphid. In this research, we [...] Read more.

Insects trigger plants to release volatile compounds that mediate the interaction with both pest and beneficial insects. Soybean aphids (Aphis glycines) induces soybean (Glycine max) leaves to produce volatiles that attract predators of the aphid. In this research, we describe the use of solid-phase microextraction (SPME) for extraction of volatiles from A. glycines-infested plant. Objectives were to (1) determine if SPME can be used to collect soybean plant volatiles and to (2) use headspace SPME-GC-MS approach to screen compounds associated with A. glycines-infested soybeans, grown in the laboratory and in the field, to identify previously known and potentially novel chemical markers of infestation. A total of 62 plant volatiles were identified, representing 10 chemical classes. 39 compounds had not been found in previous studies of soybean volatile emissions. 3-hexen-1-ol, dimethyl nonatriene, indole, caryophyllene, benzaldehyde, linalool, methyl salicylate (MeSA), benzene ethanol, and farnesene were considered herbivore-induced plant volatiles (HIPVs). For reproductive field-grown soybeans, three compounds were emitted in greater abundance from leaves infested with A. glycines, cis-3-hexen-1-ol acetate, MeSA and farnesene. In summary, SPME can detect the emission of HIPVs from plants infested with insect herbivores. Full article

(This article belongs to the Special Issue Solid Phase Micro-Extraction)

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1030 KiB

Open AccessArticle

Rapid Separation of Elemental Species by Fast Multicapillary Gas Chromatography with Multichannel Optical Spectrometry Detection following Headspace Solid Phase Microextraction

by Jacek Giersz, Krzysztof Jankowski and Monika Truskolaska

Chromatography 2015, 2(2), 239-252; https://doi.org/10.3390/chromatography2020239 - 22 May 2015

Viewed by 5718

Abstract

A method for conducting fast and efficient gas chromatography based on short multicapillaries in straight alignment combined with atomic emission detection was developed for field analysis. The strategy enables for speciation analysis of organometallic compounds. The analytes are simultaneously ethylated and preconcentrated on [...] Read more.

A method for conducting fast and efficient gas chromatography based on short multicapillaries in straight alignment combined with atomic emission detection was developed for field analysis. The strategy enables for speciation analysis of organometallic compounds. The analytes are simultaneously ethylated and preconcentrated on a solid phase microextraction (SPME) fiber placed in the headspace over the sample for 25 min. The ethylated species are then completely separated and selectively quantified within 25 s under isothermal conditions. A new miniaturized speciation analyzer has been constructed and evaluated. The system consists of a GC injection port and a lab-made miniaturized GC unit directly coupled with miniaturized plasma excitation source. The emitted light is transferred via optical fiber and registered with a miniaturized charged coupled device (CCD) based spectrometer. Working parameters for multicapillary column gas chromatography with atomic emission detector, including carrier gas flow rate, desorption temperature, and GC column temperature, were optimized to achieve good separation of analytes. Basic investigations of the fundamental properties of 5 cm-long multicapillary column, to evaluate its potential and limitations as a rapid separation unit, are presented. The adaptation of the technique for use with a SPME system and with a multichannel element-selective plasma-emission detector is highlighted. Full article

(This article belongs to the Special Issue Solid Phase Micro-Extraction)

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1408 KiB

Open AccessArticle

The Evaluation of Magnetic Polymethacrylate-based Microspheres Used for Solid Phase DNA Micro-Extraction

by Štěpánka Trachtová, Hana Zapletalová, Alena Španová, Daniel Horák, Hana Kolářová and Bohuslav Rittich

Chromatography 2015, 2(2), 156-166; https://doi.org/10.3390/chromatography2020156 - 2 Apr 2015

Cited by 5 | Viewed by 5446

Abstract

Using magnetic particles as a solid-phase extraction system is the most frequently used micro-technique for DNA isolation. Particles with a complete covering of magnetic cores by a polymer are hence preferred. Quantitative polymerase chain reaction (qPCR) was used for [...] Read more.

Using magnetic particles as a solid-phase extraction system is the most frequently used micro-technique for DNA isolation. Particles with a complete covering of magnetic cores by a polymer are hence preferred. Quantitative polymerase chain reaction (qPCR) was used for the evaluation of the polymer coating efficiency of hydrophilic magnetic poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) (P(HEMA-co-GMA)) and poly(glycidyl methacrylate) (PGMA) microspheres with/without carboxyl groups. The inhibition effect of magnetic microspheres was identified by the shift in Cq values (ΔCq) after the addition of different amounts of microspheres to PCR mixtures. With the increase of microsphere concentrations, the shift in Cq values to higher values was usually observed. P(HEMA-co-GMA) microspheres containing carboxyl groups extinguished the fluorescence at concentrations over 2 mg mL⁻¹ in a PCR mixture without any influence on the synthesis of PCR products. No PCR products (inhibition of DNA amplification) were detected in the presence of more than 0.8 mg mL⁻¹ in the PCR mixture of PGMA microspheres. Atomic force microscopy (AFM) was used for the determination of the surface morphology of the microspheres. The microspheres were spherical, and their surface was non-porous. Full article

(This article belongs to the Special Issue Solid Phase Micro-Extraction)

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1034 KiB

Open AccessArticle

Determination of Trichloroethylene in Water by Liquid–Liquid Microextraction Assisted Solid Phase Microextraction

by Mengliang Zhang and Peter De B. Harrington

Chromatography 2015, 2(1), 66-78; https://doi.org/10.3390/chromatography2010066 - 9 Feb 2015

Cited by 4 | Viewed by 7344

Abstract

A method for the determination of trichloroethylene (TCE) in water using portable gas chromatography/mass spectrometry (GC/MS) was developed. A novel sample preparation method, liquid–liquid microextraction assisted solid phase microextraction (LLME–SPME), is introduced. In this method, 20 µL of hexane was added to 10 [...] Read more.

A method for the determination of trichloroethylene (TCE) in water using portable gas chromatography/mass spectrometry (GC/MS) was developed. A novel sample preparation method, liquid–liquid microextraction assisted solid phase microextraction (LLME–SPME), is introduced. In this method, 20 µL of hexane was added to 10 mL of TCE contaminated aqueous samples to assist headspace SPME. The extraction efficiency of SPME was significantly improved with the addition of minute amounts of organic solvents (i.e., 20 µL hexane). The absolute recoveries of TCE at different concentrations were increased from 11%–17% for the samples extracted by SPME to 29%–41% for the samples extracted by LLME–SPME. The method was demonstrated to be linear from 10 to 1000 ng mL⁻¹ for TCE in water. The improvements on extraction efficiencies were also observed for toluene and 1, 2, 4-trichlorobenzene in water by using LLME–SPME method. The LLME–SPME method was optimized by using response surface modeling (RSM). Full article

(This article belongs to the Special Issue Solid Phase Micro-Extraction)

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1108 KiB

Open AccessArticle

Quantification of Carbonyl Compounds Generated from Ozone-Based Food Colorants Decomposition Using On-Fiber Derivatization-SPME-GC-MS

by Wenda Zhu, Jacek A. Koziel, Lingshuang Cai, H. Duygu Özsoy and J. (Hans) Van Leeuwen

Chromatography 2015, 2(1), 1-18; https://doi.org/10.3390/chromatography2010001 - 24 Dec 2014

Cited by 3 | Viewed by 7764

Abstract

Fruit leathers (FLs) production produces some not-to-specification material, which contains valuable ingredients like fruit pulp, sugars and acidulates. Recovery of FL for product recycling requires decolorization. In earlier research, we proved the efficiency of an ozone-based decolorization process; however, it produces carbonyls as [...] Read more.

Fruit leathers (FLs) production produces some not-to-specification material, which contains valuable ingredients like fruit pulp, sugars and acidulates. Recovery of FL for product recycling requires decolorization. In earlier research, we proved the efficiency of an ozone-based decolorization process; however, it produces carbonyls as major byproducts, which could be of concern. A headspace solid-phase microextraction with on-fiber derivatization followed by gas chromatography-mass spectrometry was developed for 10 carbonyls analysis in ozonated FL solution/suspension. Effects of dopant concentration, derivatization temperature and time were studied. The adapted method was used to analyze ozonated FL solution/suspension samples. Dopant concentration and derivatization temperature were optimized to 17 mg/mL and 60 °C, respectively. Competitive extraction was studied, and 5 s extraction time was used to avoid non-linear derivatization of 2-furfural. The detection limits (LODs) for target carbonyls ranged from 0.016 and 0.030 µg/L. A much lower LOD (0.016 ppb) for 2-furfural was achieved compared with 6 and 35 ppb in previous studies. Analysis results confirmed the robustness of the adapted method for quantification of carbonyls in recycled process water treated with ozone-based decolorization. Ethanal, hexanal, 2-furfural, and benzaldehyde were identified as byproducts of known toxicity but all found below levels for concern. Full article

(This article belongs to the Special Issue Solid Phase Micro-Extraction)

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Review

Jump to: Research

1618 KiB

Open AccessReview

Recent Developments and Applications of Solid Phase Microextraction (SPME) in Food and Environmental Analysis—A Review

by Sybille Merkle, Kim Karen Kleeberg and Jan Fritsche

Chromatography 2015, 2(3), 293-381; https://doi.org/10.3390/chromatography2030293 - 30 Jun 2015

Cited by 155 | Viewed by 25883

Abstract

Solid-phase microextraction (SPME) is a simple, sensitive, rapid and solvent-free technique for the extraction of analytes from gaseous, liquid and solid samples and takes a leading position among microextraction methods. Application of SPME in sample preparation has been increasing continuously over the last [...] Read more.

Solid-phase microextraction (SPME) is a simple, sensitive, rapid and solvent-free technique for the extraction of analytes from gaseous, liquid and solid samples and takes a leading position among microextraction methods. Application of SPME in sample preparation has been increasing continuously over the last decade. It is most often used as an automatized fiber injection system coupled to chromatographic separation modules for the extraction of volatile and semivolatile organic compounds and also allows for the trace analysis of compounds in complex matrices. Since SPME was first introduced in the early 1990s, several modifications have been made to adapt the procedure to specific application requirements. More robust fiber assemblies and coatings with higher extraction efficiencies, selectivity and stability have been commercialized. Automation and on-line coupling to analytical instruments have been achieved in many applications and new derivatization strategies as well as improved calibration procedures have been developed to overcome existing limitations regarding quantitation. Furthermore, devices using tubes, needles or tips for extraction instead of a fiber have been designed. In the field of food analysis, SPME has been most often applied to fruit/vegetables, fats/oils, wine, meat products, dairy and beverages whereas environmental applications focus on the analysis of air, water, soil and sediment samples. Full article

(This article belongs to the Special Issue Solid Phase Micro-Extraction)

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