Solid-phase Dynamic Extraction Research Articles

Preliminary Study of the Effect of Short Maceration with Cherry and Oak Wood Chips on the Volatile Composition of Different Craft Beers

In the last few years, the production and consumption of craft beers has increased notably. However, there is restricted knowledge about the potential impact of chips from different wood species on beer quality. Thus, this work aimed to evaluate the effect of the addition of wood chips from cherry and oak species—after the fermentation was completed and during a brief maceration time—on the volatile composition of three different beer groups (Ale, Lager, and Porter) through a headspace solid-phase dynamic extraction (HS-SPDE) and GC-MS analysis. Fifty-six volatile compounds from different chemical families (esters, alcohols, terpenes, acids, aldehydes, ketones, and pyrazines) were detected, identified, and considered in this study. In general, the volatile composition of the beers macerated with wood chips was very similar to that of the control beers. However, the control beers showed higher volatile compound levels. The results suggest potential interactions between beer volatile compounds and the wood chips during maceration. The outcomes of this research could be of practical interest to brewers since they could improve the knowledge of the impact of short-time contact and low wood chip concentration on the volatile composition of different craft beers.

Antimicrobial properties and volatile profile of bread and biscuits melanoidins

This work gives novel information about the antimicrobial effect and volatiles of melanoidins isolated from Maria biscuit, common and soft bread. Melanoidins were isolated from scraped and sieved crusts (1 mm), after gluten digestion, 10 kDa ultrafiltration, and diafiltration. Finally, they were freeze-dried. Headspace solid-phase dynamic extraction coupled with a gas chromatograph with a mass spectrometer was used to determine the volatile profiles. The antimicrobial effect was evaluated against isolated strains of the most relevant food spoilage and pathogen microorganisms, together with some molds and yeasts. Melanoidins from common bread exhibited the most extensive antimicrobial activities and showed the most composite volatile profile. No undesirable compounds, such as furfural and 5-hydroxy-methyl-furfural, were found in any of the melanoidins studied. The obtained data pointed out that bakery melanoidins can exert effective food technological properties as natural antimicrobials that can improve shelf-life and security of foodstuffs, together with a possible contribution to food aroma.

Screening of Volatile Compounds in Mate (Ilex paraguariensis) Tea—Brazilian Chimarrão Type—By HS-SPDE and Hydrodistillation Coupled to GC-MS

The volatile fraction of mate (Ilex paraguariensis) tea—specifically Brazilian chimarrão type, which has an odor profile comprising distinctive fresh, green, grass, and herbal notes—was investigated. Hydrodistillation in a Clevenger apparatus was employed in order to extract volatiles from the tea matrix. Headspace–solid-phase dynamic extraction (HS-SPDE) was employed to extract the volatiles from two types of infusions of this tea—a simple single infusion and a traditional preparation of consecutive infusions. Volatiles were analyzed by gas chromatography–flame ionization detection/mass spectrometry (GC-FID/MS). In total, 85 compounds were either identified or tentatively identified and semi-quantified. Semi-quantification comprised peak area integration of all the peaks (including the unidentified ones) in the chromatogram. Results obtained by hydrodistillation and by HS-SPDE were distinct, covering mostly different ranges of volatility and showing only 15 compounds in common. The identified compounds had their respective average and minimum odor thresholds and odor characteristics compiled from the literature. Several major compounds considered as key odorants in other mate tea products were not detected or only present at low levels in the samples of this research. Approximately half of the odorants identified in these samples were commonly reported in different mate tea types; the remaining 41 molecules—predominantly terpenoids (isoprenoids)—could be listed as specific to the Brazilian chimarrão type and are suggested to underlie its typical freshness.

Volatiles from Different Instars of Honeybee Worker Larvae and Their Food.

(E)-β-Ocimene was the only volatile chemical found to be emitted by whole, live worker larvae of Apis mellifera L. when sampling in the vapor phase. In addition to (E)-β-ocimene, there is evidence for the existence of other volatiles, but the changes in their composition and contents remain unknown during larval development, as are their differences from larvae to larval food. We investigated volatile components of worker larvae and larval food using solid phase dynamic extraction (SPDE) coupled with gas chromatography-mass spectrometry (GC-MS). Nine compounds were identified with certainty and six tentatively, including terpenoids, aldehydes, hydrocarbons, an ester and a ketone. The contents of volatiles in the second-instar worker larvae differ greatly from those in larvae of other stages. This is mainly attributable to terpenoids, which resulted in the second-instar worker larvae having significantly higher amounts of overall volatiles. Larval food contained significantly higher amounts of aldehydes and hydrocarbons than the corresponding larvae from the fourth to fifth-instar. We discovered volatiles in worker larvae and their food that were never reported before; we also determined the content changes of these volatiles during larval development.

Solid-Phase Extraction of Organic Substances: Unconventional Methods and Approaches

Actively developing “unconventional” methods for the solid-phase extraction (SPE) of organic substances, for example, solid-phase microextraction, solid-phase dynamic extraction, dispersive solid-phase extraction, matrix solid-phase dispersion, microextraction in a packed syringe, etc., are characterized. The main distinctive features of the methods and the fields and prospects for their application are considered. Solid-phase microextraction is most popular, mainly because of a possibility of the full automation of the separation and determination of analytes and the ease of combination with gas and liquid chromatography, as well as with other analytical methods.

Urinary excretion of heptanones, heptanoles and 2,5-heptanedione after controlled acute exposure of volunteers to n-heptane

A lack of well-established parameters and assessment values currently impairs biomonitoring of n-heptane exposure. Using controlled inhalation experiments, we collected information on urinary n-heptane metabolite concentrations and the time course of metabolite excretion. Relationships between external and internal exposure were analysed to investigate the suitability of selected metabolites to reflect n-heptane uptake.Twenty healthy, non-smoking males (aged 19–38 years, median 25.5) were exposed for 3 h to 167, 333 and 500 ppm n-heptane, each. Spot urine samples of the volunteers, collected before exposure and during the following 24 h, were analysed for heptane-2-one, 3-one, 4-one, 2,5-dione, 1-ol, 2-ol, 3-ol, and 4-ol using headspace solid phase dynamic extraction gas chromatography/mass spectrometry (HS-SPDE-GC/MS).Starting from median pre-exposure concentrations between <0.5 (3-one) and 82.9 μg/L (4-one), exposure increased the concentrations for all parameters except for 4-one. Median post-exposure concentrations ranged up to 840.4 μg/L (2-ol) and decreased with half-lifes <3 h after exposure. Non-parametric correlation analyses (n = 47, p < 0.05) revealed weak to moderate associations of volume related metabolite excretion with external exposure for 2-one, 3-one and 2,5-dione (R = 0.332–0.753). Heptanol excretion was moderately associated with exposure (R ≥ 0.509) only after creatinine adjustment.Lacking association with external exposure impedes the use of 4-one as heptane biomarker, whereas 2-ol and 3-ol turned out to be sensitive indicators of exposure if creatinine correction is applied. By providing fundamental data on a panel of eight potential heptane metabolites, our study can help to promote biological monitoring of n-heptane exposure.

Correlation Between Sensory Descriptive Analysis and Volatile Composition of Beer Using Multivariate Analysis: The Effect of the Nonvolatile Matrix on the Sensory Perception and Volatile Fraction Behavior

ABSTRACTThe effect of carbohydrate and protein content on the volatile compound release and sensory perception of four selected volatile compounds (isoamyl acetate [banana], ethyl hexanoate [apple], myrcene [dry-hop], benzaldehyde [almond]) from a model beer solution was investigated. Sensory attributes were evaluated using a trained sensory panel, while the concentration of volatile compounds were determined by 1) solid phase microextraction (SPME), 2) solid phase dynamic extraction (SPDE) coupled to gas chromatography mass spectrometry (GC/MS), and 3) stir bar sorptive extraction (SBSE) coupled to gas chromatography flame ionization (GC/FID). In addition, sensory and analytical results were correlated by multivariate analysis. Model beer samples with low levels of proteins and high levels of carbohydrates possessed the highest concentrations of isoamyl acetate, benzaldehyde, and ethyl hexanoate. Myrcene was only influenced by carbohydrate content, with a higher concentration recovered at a lower level of carbohydrate. From sensory analysis, apple and banana aroma attributes were perceived as less intense at the low protein content (P ≤ 0.05). Dry-hop aroma was perceived as more intense in samples with low carbohydrate content (P ≤ 0.05). Multivariate analysis showed a weak correlation between the sensory and instrumental data. The results illustrate that sensory perception and volatile fraction behaviors are influenced by the nonvolatile components and also demonstrate the need for caution when correlating instrumental to sensory analysis.

Optimization of a Solid Phase Dynamic Extraction (SPDE) Method for Beer Volatile Profiling

A headspace solid phase dynamic extraction coupled with gas chromatography-mass spectrometry (HS-SPDE-GC/MS) method for the analysis of the volatile fraction of beer was optimized using response surface methodology. A preliminary two-level full factorial design was performed, with extraction temperature, extraction strokes, and fill/eject speed as the main factors. The results showed that number of extraction strokes and temperature significantly affected the peak area response of the volatile compounds (p ≤ 0.05). To determine the ideal conditions for extraction, a second optimization of the significant factors was carried out using a Doehlert matrix design. The optimal conditions were identified as an extraction temperature of 60 °C and 55 extraction strokes. The optimized method was applied for the analysis of five commercial beers. A variety of compounds from different chemical classes were extracted from each sample, reflecting the effective application of the SPDE method for volatile compound extraction across different beers.

Simultaneous determination of four volatile compounds in rat plasma after oral administration of Shexiang Baoxin Pill (SBP) by HS-SPDE-GC-MS/MS and its application to pharmacokinetic studies.

In this study, a headspace, solid-phase dynamic extraction method coupled to gas chromatography-tandem mass spectrometry (HS-SPDE-GC-MS/MS) method was developed for the simultaneous determination of four volatile compounds, namely, isoborneol, borneol, muscone and cinnamaldehyde, in rat plasma after oral administration of Shexiang Baoxin Pill (SBP) using naphthalene as an internal standard (IS). The target compounds were extracted using an SPDE needle device coated with a poly (dimethylsiloxane) (PDMS) phase. The detection was achieved by GC-MS/MS in multiple reaction monitoring (MRM) mode. The optimised mass transition ion pairs (m/z) for quantitation were 95.1/67.1 for isoborneol and borneol, 85.0/67.0 for muscone, 131.0/77.0 for cinnamaldehyde and 128.1/102.1 for the IS. The parameters that affect the extraction ratio, such as the pre-incubation time, extraction temperature, number of extraction cycles, desorption volume and pH, were also optimised. The method was thoroughly validated with respect to specificity, linearity, precision, accuracy, recovery and stability. A sufficiently sensitive HS-SPDE-GC-MS/MS method was first developed in this study to determine the pharmacokinetics of volatile compounds found in rat plasma following oral administration of SBP. The method developed uses a simple procedure for plasma sample preparation and could be a promising tool for the analysis of complex volatile samples, such as traditional Chinese medicine (TCM).

Pervaporation investigation of recovery of volatile compounds from brown crab boiling juice

Pervaporation has been used to obtain aroma concentrates from brown crab boiling juice. The boiling juice and the obtained permeate have been analysed by Headspace Solid Phase Dynamic Extraction Gas Chromatography/Mass Spectrometry. The effect of feed temperature on the pervaporation performance of the membrane has been analysed. The permeate aroma profile, at 25 ℃ and 40 ℃, was different from that of the boiling juice. Enrichment factors for some of the volatile compounds were much lower than those obtained in model aqueous dilute solutions. Pervaporation performance can be significantly improved by modifying the permeant circuit to include two condensation stages.

Comparison of the sensitivity of different aroma extraction techniques in combination with gas chromatography–mass spectrometry to detect minor aroma compounds in wine

MicroVinification platforms are used for screening purposes to study aroma development in wine. These high-throughput methodologies require flavor analysis techniques that allow fast detection of a high number of aroma compounds which often appear in very low concentrations (μg/l). In this work, a selection of aroma extraction techniques in combination with gas chromatography–mass spectrometry (GC–MS) were evaluated to detect minor wine aroma compounds in low sample volume. The techniques evaluated were headspace (HS), headspace solid-phase dynamic extraction (HS-SPDE), headspace solid-phase microextraction (HS-SPME), direct immersion solid-phase microextraction (DI-SPME), stir bar sorptive extraction (SBSE) and monolithic material sorptive extraction (MMSE). DI-SPME showed the highest sensitivity as expressed by detection of the highest percentage of total aroma compounds at concentrations around 0.1μg/l. SBSE and MMSE followed DI-SPME in terms of sensitivity. HS-SPME was less sensitive but considered sensitive enough for detection of most of the volatile compounds present in highly aromatic wines. Matrix effect was shown to strongly affect aroma extraction and therefore the sensitivity of the different extraction methods.

Fingerprinting of red wine by headspace solid-phase dynamic extraction of volatile constituents

Headspace solid-phase dynamic extraction (HS-SPDE) was investigated for its applicability in quality control analysis of wine volatiles using gas chromatography-mass spectrometry. In total, 196 German red wines were analysed and 22 flavour-relevant alcohols and esters were quantified. The method detection limits were between 0.1 and 9.3 μg L(-1), allowing the dilution of the samples to decrease matrix and competition effects. Quantification resulted in a concentration range from about 1 μg L(-1) linalool up to 380 mg L(-1) 2-methyl-1-propanol. The measurement uncertainty budget was determined for all compounds in a "top-down" approach and was between 2.5 and 7.9%, with an average of 5.5%. A surveillance of the extraction performance of the HS-SPDE devices showed constant results for up to 400 extractions using one extraction needle tip. A chromatogram library for quality and authenticity control of wine samples was created using commercially available chromatogram comparison software.

Inside-Needle Extraction Method Based on Molecularly Imprinted Polymer for Solid-Phase Dynamic Extraction and Preconcentration of Triazine Herbicides Followed by GC–FID Determination

An inside-needle extraction method was developed through thermal polymerization of atrazine-molecularly imprinted polymer (MIP) on the internal surface of a stainless steel hollow needle, which was oxidized and silylated. The fabricated coating (MIP layer) for the needle was durable and showed very good chemical and thermal stability. It could be mounted on a glass syringe and be directly coupled with gas chromatographic (GC) systems. The parameters being effective on the coating and extraction processes, namely nature of oxidizing agent, silylation time, nature and amount of porogen, template-to-MIP components ratio, polymerization time and temperature, sample volume, flow rate, pH and ionic strength of the sample were investigated and optimized. The extraction needle showed high selectivity as well as a great extraction capacity for triazines. The extraction of atrazine, simazine, cyanazine, ametryn, prometryn and terbutryn using the fabricated extraction needle and followed by GC analysis resulted in detection limits of 2.6, 21, 24, 32, 38 and 42 ng mL−1, respectively. The fabricated needle proved to be applicable to the analysis of real samples by comparing the results obtained for non-spiked and spiked samples of grape juice, tap water and groundwater.

Chemical Signals of Elephant Musth: Temporal Aspects of Microbially-Mediated Modifications

Mature male African (Loxodonta africana) and Asian (Elephas maximus) elephants exhibit periodic episodes of musth, a state in which serum androgens are elevated, food intake typically decreases, aggressiveness often increases, and breeding success is enhanced. Urine is a common source of chemical signals in a variety of mammals. Elephants in musth dribble urine almost continuously for lengthy periods, suggesting that the chemicals in their urine may reveal their physiological condition to conspecifics. We investigated the volatile urinary chemicals in captive male elephants using automated solid phase dynamic extraction (SPDE) and gas chromatography-mass spectrometry (GC-MS). We found higher levels of alkan-2-ones, alkan-2-ols, and some aromatic compounds in urine from males in musth than in urine from non-musth males or from females. Levels of ketones and alcohols increased as the urine aged, likely due to microbial metabolism of fatty acids. Protein-derived aromatic metabolites also increased in abundance after urination, likely due to microbial hydrolysis of hydrophilic conjugates. We suggest that microbes may play an important role in timed release of urinary semiochemicals during elephant musth.

Sol-gel Titania-Coated Needles for Solid Phase Dynamic Extraction-GC/MS Analysis of Desomorphine and Desocodeine

Novel sol-gel titania film coated needles for solid-phase dynamic extraction (SPDE)-GC/MS analysis of desomorphine and desocodeine are described. The high thermal stability of titania film permits efficient extraction and analysis of poorly volatile opiate drugs. The influences of sol-gel reaction time, coating layer, extraction and desorption time and temperature on the SPDE needle performance were investigated. The deuterium labeled internal standard was introduced either during the extraction of analyte or directly injected to GC after the extraction process. The latter method was shown to be more sensitive for the analysis of water and urine samples containing opiate drugs. The proposed conditions provided a wide linear range (from 5-5000 ppb), and satisfactory linearity, with R(2) values from 0.9958 to 0.9999, and prominent sensitivity, LOQs (1.0-5.0 ng/g). The sol-gel titania film coated needle with SPDE-GC/MS will be a promising technique for desomorphine and desocodeine analysis in urine.

Accelerated solid-phase dynamic extraction for the analysis of biogenic volatile organic compounds in air

In this study, accelerated solid phase dynamic extraction (ASPDE) technique was used to identify biogenic volatile organic compounds (BVOCs) emitted from Norway spruce (Picea abies). Compounds that were determined in tree samples are: tricycylene, α-pinene, camphene, β-pinene, myrcene, 3-carene, p-cymene, limonene, cineole, α-phellandrene, α-terpinene, γ-terpinene and terpinolene. ASPDE showed a potential for the analysis of environmental samples as well as for field applications. This technique was further studied by using a gaseous mixture of BVOCs (sabinene, α-pinene, β-pinene, limonene, linalool, and (Z)-hexenyl acetate) and exhibited a good repeatability during all the experiments in the range of 2.5% (α-pinene) and 14.6% (linalool). However, during the analysis of samples it was observed that desorption at high temperature (230°C) can lead to the formation of artifacts, which were not observed at the desorption temperature of 100°C. Further experimental investigations revealed that monoterpenes appeared as unanticipated compounds during desorption of ASPDE samples; these compounds were degradation products of linalool.

Application of headspace solid phase dynamic extraction gas chromatography/mass spectrometry (HS-SPDE-GC/MS) for biomonitoring of n-heptane and its metabolites in blood

Solid phase dynamic extraction (SPDE) is an innovative sample preparation and enrichment technique in connection with gas chromatography (GC). Using SPDE, we developed a method for simultaneous determination of n-heptane and its mono-oxygenated metabolites heptane-4-one, 3-one, 2-one, 4-ol, 3-ol, 2-ol, and 1-ol in blood. After adjustment of various extraction and desorption parameters, method validation resulted in limits of detection (LOD) between 0.006 (heptane-4-one) and 0.021mg/L (heptane-1-ol). Intra-assay coefficients of variation ranged between 4.8% and 20.8% while relative recovery ranged between 100% and 117% (spiked concentration 0.128mg/L, n=8). The method was applied to blood samples, which have been collected from 20 volunteers after controlled inhalative exposure to 167, 333, and 500ppm n-heptane. After 3h of exposure, n-heptane and heptane-2-one were detectable in all samples in concentrations ranging up to 2.903 and 0.495mg/L, while the concentrations of the remaining analytes were closer to the respective LOD or even below. A significant linear relationship with ambient exposure (R2=0.701, p<0.001, n=55) was found for n-heptane in blood, which could be helpful for evaluation of biological exposure limits in future. Due to its high abundance in blood, 2-heptanone could be an interesting candidate as a biomarker also in alternative matrices such as urine or saliva.

Optimization of Modern Analytical SPME and SPDE Methods for Determination of Trans-2-nonenal in Barley, Malt and Beer

Trans-2-nonenal is an aldehyde contributing to an unpleasant off-flavor and odor of rancid butter in stored beer. The automated solid-phase microextraction technique (SPME) coupled with gas chromatography (GC) and solid-phase dynamic extraction (SPDE) coupled with gas chromatography were optimized and introduced to determine trans-2-nonenal in barley, malt and beer. Five types of SPME fibers coated with different stationary phases (100 μm PDMS, 65 μm PDMS/DVB, 85 μm CAR/PDMS, 50/30 μm DVB/CAR/PDMS, 85 μm PA) and two needles (PDMS, PDMS/AC) were compared and tested for their efficiencies in the headspace (HS) SPME and SPDE determination of trans-2-nonenal in barley, malt and beer. The highest extraction efficiency of HS-SPME was achieved with the PDMS/DVB fiber, and addition of 1.5 g of NaCl, extraction time was 20 min at 60 °C. The highest extraction efficiency of HS-SPDE was obtained with the PDMS needle, 15 extraction strokes at 60 °C and addition of 1.5 g of NaCl. Trans-2-nonenal was identified with the method of HS-SPME coupled gas chromatography-mass spectrometry (GC–MS); the samples were analyzed using the HS-SPME-GC-coupled gas chromatography-flame ionization detector (GC-FID) technique.

Dynamic SPME를 이용한 공기 중 지방산 분석

Abstract In this study, the detection limits of lower fatty acids in air were investigated by using Dynamic SPME(Solid Phase Micro-Extraction), i.e. improved Head Space - SPME method(HS-SPME). This Dynamic SPME, called SPDE(Solid Phase Dynamic Extraction), is the analytical method for volatile compounds in air with the extraction by using a stainless steel needle of which inner surface is coated with adsorption material and following the gas chromatographic analysis by inserting the needle into a injection port of GC and subsequently, desorption of the volatile compounds into a gas- chromatographic column. Extraction was carried out by passing the sample air through the needle with a suction pump which has been used for a detection tube. The result of measurement for the 6 lower fatty acids showed that the detection limits ranged from 0.10 ppm to 0.44 ppm and the linear correlation coefficients were over 0.99. Relative standard deviations obtained from 5 analytical repetition of a ca. 1.6 ppm standard mixture were in the range of 1.87%～2.47%. This method has been shown to be a adequate for the measuring C2 ～C5 fatty acids in air in the concentrations of over several hundreds ppb. Key Words: Environmental analysis, Volatile fatty acids, Dynamic SPME, SPDE

Analysis of Volatile Profiles of Fermenting Grape Must by Headspace Solid-Phase Dynamic Extraction Coupled with Gas Chromatography−Mass Spectrometry (HS-SPDE GC-MS): Novel Application To Investigate Problem Fermentations

The occurrence of stuck and sluggish wine fermentations is a persisting problem in the wine industry worldwide. This study illustrates the suitability of headspace solid-phase dynamic extraction coupled with gas chromatography-mass spectrometry (HS-SPDE GC-MS) for wine analysis and the subsequent application to discriminate between control and problem fermentations using partial least-squares discriminant analysis (PLS-DA) models. The specific analytical technique is relatively new and has not yet to the authors' knowledge been evaluated for the analysis of wine within this context of problem fermentations. HS-SPDE GC-MS was used to determine 68 volatile compounds (higher alcohols, fatty acids, esters, and carbonyl compounds) in 94 monovarietal fermenting must samples consisting of 56 red and 38 white cultivars. PLS-DA models showed the potential to discriminate between control and problem fermentations using corrected peak area headspace data for the 68 analytes. This possibility to discriminate between problem and control fermentations with only the headspace data could possibly be applied for the prediction of problem fermentations in future studies and to better understand the chemical causes of problem fermentations.