TY - JOUR. T1 - Aqueous phase hexylchloroformate derivatization and solid phase microextraction. T2 - Determination of benzoylecgonine in urine by gas chromatography-quadrupole ion trap mass spectrometry. AU - Hall, Brad J.. AU - Parikh, Aashish R.. AU - Brodbelt, Jennifer S.. PY - 1999/5. Y1 - 1999/5. N2 - A derivatization/solid phase microextraction (SPME) method for the determination of benzoylecgonine in urine was developed. The derivatization is conducted directly in 1 mL of urine while sonicating for 3 min with 12 μL of hexyl chloroformate and 70 μL of a mixture containing acetonitrile:water:hexanol:2-dimethylaminopyridine (5:2:2:1 v/v), yielding benzoylecgonine hexyl ester (BHE) as the product. After the 3 min period, an aliquot of 250 μL is transferred to a vial for SPME. After the desired extraction time the 100 μm polydimethylsiloxane SPME fiber was transferred to the GC-MS for separation and analysis with a quadrupole ion trap mass spectrometer. The hexyl chloroformate ...
Title: Characterization and Optimization of a High Surface Area-Solid Phase Microextraction Sampler for the Collection of Trace Level Volatile Organic Compounds in the Field Shannon Scott McDonald, Master of Science in Public Health, 2006 Directed By: Gary Hook, CDR, USN Assistant Professor, Department of Preventive Medicine and Biometrics A prototype rapid, high volume air sampling device based on Solid Phase Microextraction (SPME) has been developed for the collection of trace level volatile organic compounds (VOCs). The High Surface Area-Solid Phase Microextraction (HSA- SPME) device contains ten times more polymer than traditional SPME fibers and is uniquely designed to optimize compound uptake at higher flow rates. This study evaluated the extraction efficiency at six air sampling flow rates ranging from 0.1 L/min to 10 L/min and compared total compound extraction at the two extreme flow rates. A 10 ppbv concentration of 39 volatile organic compounds was used. ...
Solid phase microextraction (SPME) is a solventless extraction technique that combines sample preparation and sample introduction into a gas chromatograph into a single step. For the past 20 years, solid-phase micro-extraction (SPME) has been used in numerous fields such as: food analysis, including juices, alcohols fruits and vegetables for volatiles, aroma, caffeine, fatty esters, environmental applications including volatile organic contaminants, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, phenols, pesticides, steroids, herbicides, acid/neutral/base compounds, and organometallic compounds from water, air, soil, sludge, and sediment samples and in biomedical analysis. This work demonstrates the extension of the limitations of SPME with respect to extraction and analysis of a) extension of headspace SPME to larger polycyclic aromatic hydrocarbons from fish oil b) less volatility analytes, combination of SPME-Gas Chromatograph -Mass Spectrometer -Mass Spectrometer (SPME-GC-MS-MS) to
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A solid phase microextraction (SPME) method was applied for the extended monitoring survey of priority pesticides for the European Union, for 12 months, in Kala
Article Field Sampling for Pesticides, Using Solid Phase Microextraction/Capillary GC. An SPME portable field sampler can be used to extract analytes from samples in the field, then store them for up to 3 days, or longer, before performing the analys...
article{191ea318-159e-43da-9392-05ee7bf33a0d, author = {Wady, Loay and Bunte, Annicka and Pehrson, Christina and Larsson, Lennart}, issn = {1872-8359}, language = {eng}, number = {3}, pages = {325--332}, publisher = {Elsevier}, series = {Journal of Microbiological Methods}, title = {Use of gas chromatography-mass spectrometry/solid phase microextraction for the identification of MVOCs from moldy building materials.}, url = {http://dx.doi.org/10.1016/S0167-7012(02)00190-2}, volume = {52}, year = {2003 ...
As submitted by the proposer: Chemical forensics is a nascent field that collects and attributes chemical information of physical evidence to their sources. Ideally, from a chemical forensic analysis, one can identify chemical signatures of physical evidence and use them to classify or trace the source of it. We propose to use heated headspace solid phase microextraction coupled to gas chromatography/mass spectrometry (HHS-SPME-GC/MS) as an analytical platform for the collection of chemical signatures of physical evidence.
GARBARINO, JUAN A et al. VOLATILE COMPOUNDS OF LITHRAEA CAUSTICA (LITRE) DETERMINATED BY SOLID PHASE MICRO-EXTRACTION (SPME). Bol. Soc. Chil. Quím. [online]. 2002, vol.47, n.4, pp.567-569. ISSN 0366-1644. http://dx.doi.org/10.4067/S0366-16442002000400030.. The head space of the aerial parts of Lithraea caustica was analyzed by Solid Phase Micro-Extraction (SPME) technique, obtaining as main volatile compounds the monoterpenes, myrcene, a -pinene, , p-cymene and limonene, as well as the sesquiterpene caryophylene.. Palabras clave : Lithraea caustica; Anacardiaceae; Solid Phase Micro-Extraction; head space components; monoterpenes, sesquiterpenes. ...
In recent years, advances in direct sample to mass spectrometry (MS) techniques have allowed for the application of these methods towards quantitative analysis in complex matrices such as biofluids and tissue. However, the predictable limitations of these technologies, such as ionization suppression, poor sensitivity at trace levels, and narrow linear dynamic range, have been the driving force toward the development of methods that efficiently integrate sampling, sample cleanup, and analyte collection and ionization. In this context, the direct interface of microextraction technologies and MS has undoubtedly revolutionized the speed, efficacy, and robustness with which complex matrices can be scrutinized. In this thesis, numerous strategies recently developed for the direct and efficient coupling of Solid Phase Micro Extraction (SPME) and MS are presented towards the analysis of complex matrices. Aiming to supply a range of technologies suited for diverse applications, different SPME geometries ...
Human scent, or the volatile organic compounds (VOCs) produced by an individual, has been recognized as a biometric measurement because of the distinct variations in both the presence and abundance of these VOCs between individuals. In forensic science, human scent has been used as a form of associative evidence by linking a suspect to a scene/object through the use of human scent discriminating canines. The scent most often collected and used with these specially trained canines is from the hands because a majority of the evidence collected is likely to have been handled by the suspect. However, the scents from other biological specimens, especially those that are likely to be present at scenes of violent crimes, have yet to be explored. Hair, fingernails and saliva are examples of these types of specimens. In this work, a headspace solid phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) technique was used for the identification of VOCs from hand odor, hair, fingernails and
The current doctoral thesis presents the development of an analytical procedure for the quantitative analysis of fatty acid ethyl esters (FAEE) in hair and in skin surface lipids using headspace solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) as well as a method based on high-performance liquid chromatography with photodiode array detection (HPLC-DAD) to determine squalene concentrations in lipid extracts. The results obtained from analysis of samples from different alcohol consuming groups showed that FAEE are suitable markers for long-term alcohol misuse. Concerning sensitivity and specifity they are at least as good as other commonly used markers like GGT, CDT or MCV. The following provisional cut-off values were established: for chronically excessive alcohol consumption, the sum of the four FAEE (ethyl myristate, ethyl palmitate, ethyl oleate and ethyl stearate) found in the highest mean concentrations should be , 1 ng/mg in hair; for non-drinkers, ...
Case report: We present the case of a 48 year old woman, with severe persistent allergic asthma, despite level 4 (GINA) medical treatment, who initiated omalizumab in order to control her nocturnal symptoms and her frequent unscheduled medical visits. Before treatment and at 12 weeks: clinical evaluation with ACT was registered; lung function, FeNO, IgE and eosinophils were measured. Two-dimensional gas chromatography (GC ´GC-ToFMS) combined with headspace solid phase microextraction (HS-SPME) was applied to the untargeted study of the volatile metabolomic urine profile. ...
Product guides, articles, and application notes describing the use of SPME products in sample preparation and chromatographic analysis.
Headspace solid phase microextraction and gas chromatography/mass spectrometry were used to identify and quantify four odd-numbered methylketones in commercial Cognac brandies. These ketones are in part responsible for the desirable and complex characteristic called rancio charentais or Cognac rancio which is found in grape brandies aged in oak barrels for several decades. The ketones 2-heptanone, 2-nonanone, 2-undecanone and 2-tridecanone form through β-oxidation and decarboxylation of long-chain fatty acids originating from yeast metabolism. The concentrations of these ketones increased with Cognac age classification in the 42 brandies analysed, and 2-heptanone was present at the highest concentration in most samples. The average concentrations and rates of formation decreased with increasing chain length. Total concentrations ranged from 21 to 328 µg l−1. The esters propyl octanoate and ethyl octanoate followed the same trend as the methylketones and appear to play an additional role ...
By controlling the polarity and thickness of the coating on the fiber, maintaining consistent sampling time, and adjusting several other extraction parameters, an analyst can ensure highly consistent, quantifiable results from low concentrations of analytes.
The original SPME fibers were manufactured with 24 gauge needles, and these continue to work well for manual sampling. Fibers with 23 gauge needles are highly recommended for use with autosamplers, and for the Merlin Microseal® system as well as other septum-less seals.
1. Chai Mee Kin and Tan Guan Huat. Comparison of different types of coating in headspace solid-phase microextration for the analysis of pesticide residues in vegetables and fruits. 2008. Malaysian Journal of Analytical Science. Vol 12(2). 444-450. 2. Chai Mee Kin, Tan Guan Huat and Asha Kumari. Application of solid-phase microextraction for the determination of pesticides in vegetables samples by gas chromatography with an electron capture detector. 2008. Malaysian Journal of Analytical Science, Vol 12, No 1, Pg 1-9. 3. Chai Mee Kin, Tan Guan Huat and Asha Kumari. Headspace solid- phase microextraction in combination with gas chromatography-mass spectrometry for the rapid screening of pesticide residues in vegetables and fruits. 2007. Malaysian Journal of Chemistry. Vol 9, No. 1, Pg 018-023. 4. Chai Mee Kin, Tan Guan Huat and Asha Kumari. Method development of determination of pesticide residues in vegetables and fruits by using solid-phase microextraction. 2006. Malaysian Journal of Chemistry. ...
Determination of 1,8 Cineole in Fresh Rosemary and Sage Leaves by Solid-phase Microextraction and Gas Chromatography/Mass Spectrometry
A method and apparatus for automatically performing liquid microextraction on liquid samples includes the steps of controlling movement of a syringe between a cleaning station, a sample station containing a plurality of discrete sample vials and an instrument injector station. Movement of the syringe is controlled automatically for cleaning the syringe, obtaining a sample of each sample in each discrete sample vial, one at a time, and injecting the collected sample into the instrument injector, and then repeating the sequence steps for all discreet samples.
Montepulciano is one of the most famous and important red-berried grapes of Italy. This article presents and discusses a comparative study of aroma profile and phenolic content of the Montepulciano wine from the Marches and the Abruzzo regions. The volatile composition of wines was determined by using head- space solid phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). The PDMS fibre was chosen. The dominating esters in Montepulciano wines were ethyl hexa- noate, ethyl decanoate, and ethyl octanoate, whereas phenyl ethanol and 3-methyl-1-butanol were dom- inating alcohols. Phenolic compounds, namely gallic acid, p-coumaric acid, trans-ferulic acid, caffeic acid, trans-resvera- trol, (+)-catechin and ( )-epicatechin, were examined using HPLC-MS with direct injection of wine sam- ples. The total phenolic content of the analysed wines was in the range of 30.4-61.9 mg l 1. The presence of high amounts of esters seems to characterise the volatiles of ...
The analysis of volatiles in solids is a common analytical problem. Examples include volatile aroma compounds in foods and plant materials (coffee, tea, and herbs), residual fragrances from soaps and fabric softeners on textiles, and volatiles in polymer resins, films and plastic products. Several techniques are available that allow direct analysis of the volatiles in a variety of solid matrices with little or no sample preparation. Static headspace GC (HS-GC) is probably the most commonly applied technique for analysis of volatiles in solids. Direct thermal desorption (TDS), sometimes referred to as dynamic headspace analysis, and Solid Phase Microextraction (SPME) are alternative techniques that can now be automated. The relative sensitivity of these techniques, and the strengths and limitations of each when applied to a variety of solid matrices should be considered when choosing the most appropriate approach for a new analysis. Until now a direct comparison of these techniques for a variety ...
The analysis of flavor compounds in dairy products such as milk, cream, yogurt and cheese as well as their blends with several ingredients usually requires cumbersome sample preparation steps such as liquid/liquid extraction, solid phase extraction or distillation techniques, often with the drawback of organic solvent use. Headspace and purge & trap methods do not use organic solvents, but their analyte range is restricted to volatile compounds and therefore characterize compounds that contribute to the aroma/smell of a sample, not flavor/taste. In addition heating of the sample should be avoided since this would lead to reaction products which dramatically modify the flavor and taste of any dairy product. The sensitivity of solid phase microextraction (SPME) is limited by the small amount of sorptive material that can be coated on the fibers. A new extraction technique, Stir Bar Sorptive Extraction (SBSE), that overcomes the major problems with classical extraction techniques is applied in this ...
A combined gas chromatography-mass spectrometry (GC-MS) with headspace solid-phase microextraction (HS-SPME) method has been employed for the analysis of the flavor volatiles of some Iranian rice cultivars (Domsiah, Deylamani, Hashemi, Shirodi and Tarom). The samples were grown in different cities of Mazandaran province. The sampling procedure and chromatographic conditions were same for all samples. The separated chemicals were tentatively identified from their corresponding mass spectra (NIST mass libraries). A total of 49, 31, 29, 16 and 24 peaks were identified and assigned to Domsiah, Deylamani, Hashemi, Shirodi and Tarom rice samples, respectively. The volatile components identified in the five rice cultivars belong to the chemical classes of aldehydes, ketones, alcohols and heterocyclic compounds, as well as fatty acids and esters, phenolic compounds, hydrocarbons, etc. The main identified chemicals in these samples were not identical while some minor chemicals were same, which indicate the
A porous protective sheath for active extraction media used in solid phase microextraction (SPME). The sheath permits exposure of the media to the environment without the necessity of extending a fragile coated fiber from a protective tube or needle. Subsequently, the sheath can pierce and seal with GC-MS septums, allowing direct injection of samples into inlet ports of analytical equipment. Use of the porous protective sheath, within which the active extraction media is contained, mitigates the problems of: 1) fiber breakage while the fiber is extended during sampling, 2) active media coating loss caused by physical contact of the bare fiber with the sampling environment; and 3) coating slough-off during fiber extension and retraction operations caused by rubbing action between the fiber and protective needle or tube.
In this work, the volatile profiles of smoked and non-smoked Iranian rice were identified, and their relative abundance was calculated and compared. Headspace solid-phase microextraction together with gas chromatography-mass spectrometry (SPME-GC-MS) were used to extract and identify the volatile compounds. The main groups of volatiles in Iranian rice were aldehydes, ketones, phenol derivatives, furans, linear hydrocarbons, esters and terpenes. The chemical family aldehydes was the most abundant one in the profile of non-smoked rice, while phenol derivatives and furans predominated in smoked samples. This study is the first one reporting comparative data of volatile compounds between smoked and non-smoked Iranian rice.
In this study, three kinds of Zeolite imidazolate framework-8 (ZIF-8), synthesized by solvothermal, stirring and ball-milling method, were fabricated on the stainless steel wire via sol-gel technique. These fibers were used as solid phase microextraction (SPME) coating materials and applied for analyzing 16 polycyclic aromatic hydrocarbons (PAHs) and 11 nitro polycyclic aromatic hydrocarbons (NPAH ...
Gasification of biomass will likely play an important role in the production of energy and chemicals in a future sustainable society. However, during gasification impurities, such as tars, will be formed. Tars may cause fouling and blockages of equipment downstream the gasifier. It is therefore important to minimize the formation of tars, alternatively to remove the formed tars. These processes need to be monitored, which makes it necessary to develop tar analysis methods suitable for this task.. This work describes the development of two tar analysis methods, an on-line method based on a photoionization detector (PID) and an off-line method based on solid phase microextraction (SPME). Both methods were successfully validated against the established solid phase adsorption (SPA) method.. The method based on PID was shown to have a very fast response time. Furthermore, the PID method is selective towards tar, but only limited information will be obtained regarding the composition of the tar ...
Meropenem is a widely used antimicrobial for the treatment of infections associated with the use of invasive medical devices in intensive care unit patients. These treatments are not always effective, in fact, in-vitro studies have demonstrated the difficulty of antimicrobials to penetrate into the biofilm, however in-vivo studies of the effect of these compounds is a trend, mostly because of the complexity of pulmonary samples extracted from ETTs. Therefore, the objective of this study was to evaluate in-tube solid phase microextraction (in-tube SPME) coupled to capillary liquid chromatography (CapLC) with DAD to determine meropenem in ETTs in order to estimate the penetration capability into the biofilm ...
A new sensitive, selective, fast and accurate technique for online sample preparation was developed. Microextraction in a packed syringe (MEPS) is a new miniaturised, solid-phase extraction (SPE) technique that can be connected online to GC or LC without any modifications. In MEPS approximately 1 mg of the solid packing material is inserted into a syringe (100-250 ml) as a plug. Sample preparation takes place on the packed bed. The bed can be coated to provide selective and suitable sampling conditions. The new method is very promising. It is very easy to use, fully automated, of low cost and rapid in comparison with previously used methods. The determination of polycyclic hydrocarbons (PAHs) in water was performed using MEPS as sample preparation method online with gas chromatography and mass spectrometry (MEPS-GC-MS). The results from MEPS as sample preparation were compared with other techniques such as stir bar sorptive extraction (SBSE) and solid-phase microextraction (SPME). The method was ...
Palm olein is currently considered to be one of the best options for deep-frying, but as with any other edible oil, during frying, deteriorative reactions produce off-flavor compounds that reduce the oil sensory quality. This study assessed the odor significance of the volatiles formed during 136 h of deep-frying a chicken product in palm olein, aiming to identify potential markers of the oil sensory quality during frying. The volatiles were isolated by solid phase microextraction, and identified by GC-MS. Trained judges assessed the odor intensity and quality of the volatiles formed during frying, evaluating the GC effluents through a GC-olfactometry technique called OSME. Two hundred and eight volatiles were detected by GC/MS in the palm olein after 136 h frying. Of these, heptanal, t-2-heptenal, decanal and t-2-undecenal were identified as potential markers of the sensory quality of palm olein during frying. Hexanal, pentanal and pentane, usually associated with lipid oxidation, showed no ...
Volatile organic compounds were rapidly sampled and concentrated from water in 5 seconds using a CUSTODION solid phase microextraction syringe. Compounds were analyzed on-site using the TRIDION portable gas chromatograph-toroidal ion trap mass spectrometer. ...
Here, a method to characterize edible oils and edible oil mixtures through fingerprinting and the isolation of individual analyte differences is reported. Aroma and flavor analytes in extra virgin olive, olive, peanut, grapeseed, and vegetable oils were sampled with headspace solid-phase microextraction (HS-SPME).
Solid Phase Microextraction with Polystyrene-Poly(dimethylsiloxane) block copolymers, Andrew Schlaus and Rebecca Lyons, Advisor. ...
A simple solventless injection method was introduced based on the using of a solid-phase microextraction (SPME) fiber for injection of large amounts of the analytes extracted by the magnetic solid phase extraction (MSPE) procedure. The resulted extract from MSPE procedure was loaded on a G-coated SPME fiber, and then the fiber was injected into the gas chromatography (GC) injection port. This method combines the advantages of exhaustive extraction property of MSPE and the solvent-less injection of SPME to improve the sensitivity of the analysis. In addition, the analytes were re-concentrated prior to inject into the gas chromatography (GC) inlet because of the organic solvent removing from the remaining extract of MSPE technique. Injection of the large amounts of analytes was made possible by using the introduced procedure. Fourteen polycyclic aromatic hydrocarbons (PAHs) with different volatility were used as model compounds to investigate the method performance for volatile and semi-volatile ...
A highly efficient, simple and rapid method, injection-ultrasound-assisted emulsification microextraction based on using low-density organic solvents followed by high-performance liquid chromatography-ultraviolet detection, was developed for the dete
Magnetic Stirring-Assisted Dispersive Liquid? Liquid Microextraction of Naringenin from Grapefruit and Its Determination by High Performance Liquid Chromatography
We have evaluated a vortex-assisted emulsification microextraction (VAEME) procedure followed by in-syringe ultrasound-assisted back-microextraction for the determination of nine haloacetic acids in waters of different nature, using high-performance liquid chromatography with diode array detection. The optim
For world-wide use, there was a need for an increased upper storage temperature for BioGaia AB´s oil-based probiotic drops containing L. reuteri. The main aim of this study was to investigate volatiles emerging from the product during different storage temperatures, by solid-phase microextraction in conjunction with analyses with gas chromatography/mass spectrometry (SPME/GCMS). Absorption of volatiles on Tenax in combination with GC analysis equipped with an olfactometry outlet (Tenax/GC-O) was also executed. Sensory properties of the product were documented by a sensory panel. Amount of L. reuteri, total aerobic bacteria, peroxide values and free fatty acids were analysed. Increased storage temperature from 5°C to 25°C did not influence the parameters studied significantly and in-use samples did not differ from controls. In samples stored at 30°C, more volatiles and peroxides were formed and the samples exhibited darker colours. Possible explanations are lipid oxidations, lipid hydrolyses, ...
GARBARINO, JUAN A et al. VOLATILE COMPOUNDS OF LITHRAEA CAUSTICA (LITRE) DETERMINATED BY SOLID PHASE MICRO-EXTRACTION (SPME). Bol. Soc. Chil. Qu m., Dec 2002, vol.47, no.4, p.567-569. ISSN 0366- ...
There is a growing interest in monitoring levels of biologically active compounds in living systems in their natural environments. These efforts are a significant departure from conventional sampling techniques, where a portion of the system under study is removed from its natural environment, and the compounds of interest extracted and analyzed in a laboratory environment. There are two main motivations for exploring these types of investigations. The first one is the desire to study chemical processes in association with the normal biochemical milieu of a living system, and the second one is the lack of availability or impracticality of removing suitable samples from a living system, frequently because of size.. In the presentation, I will describe the use of solid-phase microextraction (SPME) for in vivo sampling of endogenous compounds, drugs and metabolites in the tissue of freely moving animals as well as humans, which eliminates the need for tissue withdrawal in order to obtain ...
In this work we apply Definitive Screening Designs (DSD) to optimize HS-SPME extraction in order to analyze volatile fatty acids (VFA) present in wine samples. The purpose is the simultaneous optimization of seven extraction parameters (responses - the chromatographic area of nine analytes). Both qualitative and quantitative extraction parameters (factors) were considered: a two-level qualitative variable, the fiber coating, and six quantitative variables, namely the pre-incubation time, the extraction time and temperature, the headspace/sample volume, the effect of agitation during extraction and the influence of the ethanol content. Optimization w.r.t. analytes chromatographic responses was carried out both individually (response by response) and altogether, by modelling the responses in the latent variable space (i.e., explicitly considering their underlying correlation structure). The analysis in the latent variable space was particularly informative, allowing the simultaneous optimization ...
Fibers having at least one near-infrared fluorescing compound associated therewith are prepared by contacting the fibers with the fluorescing compound(s) dissolved in an organic solvent. Suitable organic solvents include ketones and alcohols. The fibers may subsequently be air-dried to remove any remaining volatiles. Fibers coated with the marker solution desirably have less than 1 weight percent of the marker coated thereon.
Xie, W.; Pawliszyn, J.; Mullett, W. M.; Matuszewski, B. K. Comparison of solid-phase microextraction and liquid-liquid extraction in 96-well format for the determination of a drug compound in human plasma by liquid chromatography with tandem mass spectrometric detection. Journal of Pharmaceutical and Biomedical Analysis (2007), 45(4), 599-608 ...
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Hands-on training in techniques using CTC instrumentation: These courses include 50% practical exercises in the laboratory, with a maximum of 4 delegates and are available as scheduled courses as well as being taught both on and offsite, tailored and besoke. 1-day Hands-on Headspace 1-day Hands-on Solid-Phase Micro-Extraction (SPME)
How would full-length sizing a case increase the headspace measurement on a .223 case, and charging/seating/crimping decrease the headspace measurement?? This weekend, I started taking headspace measurements on some 223 cases in my stockpile in various states on the way to being reloaded, in hopes of starting the process of setting up my new Dillon 650 for reloading 223. I measured unprepped and prepped cases, as well as fully loaded rounds (definitions included below). All of the work
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The aroma of milk has been often defined as bland and pleasant, yet characteristic. Conventional thermal processing of milk can certainly extend shelf life, but inevitably changes its flavor. High pressure processing has been suggested as an alternative for milk pasteurization with improved fresh flavor retention. The objective of this project was to study off-flavor volatile formation in milk subjected to high hydrostatic pressure combined with moderate heating. Two sensitive and accurate new techniques were developed for the analysis of off-flavor compounds. Solid-phase microextraction/gas chromatography with flame ionization detection was used for the analysis of aldehydes, ketones, and dimethyl sulfide. Solid-phase microextraction/gas chromatography with pulsed flame photometric detection was used for the selective analysis of trace sulfur compounds. Milk subjected to different treatment combinations of pressure, temperature and time showed that aldehydes formation is promoted during high ...
High concentrations of 5-hydroxymethylfurfural (HMF) in honey provide an indication of overheating under inappropriate storage conditions or aging. Conventional methods for determining HMF are cumbersome and require expensive equipment or hazardous reagents. Hence the aim of this study was to propose a new analytical tool for HMF determination in honey, using a low cost acoustic wave sensor. Volatile organic compounds (VOCs) of honey samples were extracted, using the solid phase microextraction (SPME) technique, and HMF was quantified, using a piezoelectric quartz crystal with gold electrodes coated with a layer of decamolybdodivanado phosphoric acid, sensitive to HMF. The reliability of the proposed method was confirmed after comparing the results of HMF quantification with those obtained by the conventional spectrophotometric White method, and no statistical differences were found (alpha = 0.05). (C) 2016 Elsevier Ltd. All rights reserved.
The first identification of a sex pheromone of a pine sawfly (Hymenoptera, Diprionidae) dates back almost thirty years. Since then, female-produced pheromones of over twenty diprionid species have been investigated by solvent extraction followed by separation and identification. However, no study has shown what the females actually release. Collection of airborne compounds using absorbtion on charcoal filter as well as solid phase microextraction (SPME) followed by analysis employing gas chromatography combined with mass spectrometry (GC-MS), revealed an unusual system in Diprion pini, in which the pheromone precursor alcohol, 3,7-dimethyl-2-tridecanol, is released together with acetic, propionic, butyric and isobutyric acids. The corresponding acetate, propionate and butyrate esters of 3,7-dimethyl-2-tridecanol were also found in the samples. All esters were electrophysiologically active, and the propionate and isobutyrate were attractive in trapping experiments. Based on these and earlier ...