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1.
Saito Y Ueta I Ogawa M Abe A Yogo K Shirai S Jinno K 《Analytical and bioanalytical chemistry》2009,393(3):861-869
A miniaturized sample preparation technique that uses a fine-fiber-packed needle as the extraction medium is reviewed, especially
in relation to its application to the analysis of volatile organic compounds by gas chromatography. When the needle was packed
longitudinally with a bundle of fine filaments (12 μm o.d.) which were also surface-coated with polymeric materials, successful
sample preconcentration was obtained. Improved sensitivity was also established by introducing simultaneous derivatization
reactions into the extraction process in the fiber-packed needle. The storage performance of the needle clearly demonstrated
the potential of the technique for typical on-site sampling during environmental analysis. In this short review, the fiber-packed
extraction needle developed by the authors is summarized along with applications that use the fiber-packed needle as a miniaturized
extraction device. 相似文献
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3.
R. Binetti S. Di Marzio P. Di Prospero L. Gramiccioni G. Viviano G. Ziemacki 《Chromatographia》1986,21(12):701-704
Summary A simple and accurate headspace-GC method is described to determine the amount of ethylene oxide which has been collected
from air using adsorption tubes containing activated charcoal and a relatively safe desorbing agent (N,N-dimethyl acetamide).
The detection limit is 40μg/m3. 相似文献
4.
A sample preparation procedure was developed for the determination of atrazine in freshwater biofilms by gas chromatography-mass spectrometry. Different methods of sample preservation (immediate extraction, deep-freezing, cooling, vacuum-drying, freeze-drying) were tested for atrazine pretreated freshwater biofilms, followed by combined liquid- and solid-phase extraction (SPE). The immediate extraction of atrazine with acetonitrile, and a SPE, proved to be the best sample preparation procedure. Applying our method, atrazine pollution of the Lake Velence (Hungary) could be detected in the biofilms. At the same time in the lake freshwater samples, prepared by SPE and analyzed the same way, the atrazine concentration did not exceed the limit of detection. 相似文献
5.
Jialiang PanAuthor Vitae Chengjiang ZhangAuthor VitaeZhuomin Zhang Gongke Li 《Analytica chimica acta》2014
Sample preparation is still considered as the bottleneck of the whole analytical procedure, and efforts has been conducted towards the automation, improvement of sensitivity and accuracy, and low comsuption of organic solvents. Development of online sample preparation techniques (SP) coupled with liquid chromatography (LC) is a promising way to achieve these goals, which has attracted great attention. This article reviews the recent advances on the online SP-LC techniques. Various online SP techniques have been described and summarized, including solid-phase-based extraction, liquid-phase-based extraction assisted with membrane, microwave assisted extraction, ultrasonic assisted extraction, accelerated solvent extraction and supercritical fluids extraction. Specially, the coupling approaches of online SP-LC systems and the corresponding interfaces have been discussed and reviewed in detail, such as online injector, autosampler combined with transport unit, desorption chamber and column switching. Typical applications of the online SP-LC techniques have been summarized. Then the problems and expected trends in this field are attempted to be discussed and proposed in order to encourage the further development of online SP-LC techniques. 相似文献
6.
Sample preparation for both environmental and more importantly biological matrices is a bottleneck of all kinds of analytical processes. In the case of proteomic analysis this element is even more important due to the amount of cross‐reactions that should be taken into consideration. The incorporation of new post‐translational modifications, protein hydrolysis, or even its degradation is possible as side effects of proteins sample processing. If protocols are evaluated appropriately, then identification of such proteins does not bring difficulties. However, if structural changes are provided without sufficient attention then protein sequence coverage will be reduced or even identification of such proteins could be impossible. This review summarizes obstacles and achievements in protein sample preparation of urine for proteome analysis using different tools for mass spectrometry analysis. The main aim is to present comprehensively the idea of urine application as a valuable matrix. This article is dedicated to sample preparation and application of urine mainly in novel cancer biomarkers discovery. 相似文献
7.
Summary Air sampling of ethylene oxide on active charcoal tubes followed by GC analysis is a frequently proposed method. This paper
studies just to what extent it can be used, defining its limitations (concentration range, influence of ambient temperature
and relative humidity), which are seldom taken seriously into account. This method proves inadequate to determine low pollution
levels, i.e. around 2 mg m−3. 相似文献
8.
A novel in-needle sample preparation device has been developed for the determination of volatile aldehydes in gaseous samples.
The needle device is designed for the gas chromatographic (GC) analysis of aldehydes and ketones commonly found in typical
in-house environments. In order to prepare the extraction device, a bundle of polymer-coated filaments was longitudinally
packed into a specially designed needle. Derivatization reactions were prompted by 2,4-dinitrophenylhydrazine (NDPH) included
in the needle, and so the aldehydes and ketones were derivatized to the corresponding hydrazones and extracted with the extraction
needle. A reproducible extraction needle preparation process was established, along with a repeatable derivatization/extraction
process that ensures the successful determination of aldehydes. The storage performance of the extraction needle was also
evaluated at room temperature for three days. The results demonstrate the successful application of the fiber-packed extraction
device to the preparation of a gaseous sample of aldehydes, and the future possibility of applying the extraction device to
the analysis of in-house environments. 相似文献
9.
Comparison of QuEChERS sample preparation methods for the analysis of pesticide residues in fruits and vegetables 总被引:1,自引:0,他引:1
Steven J. Lehotay Kyung Ae Son Hyeyoung Kwon Urairat Koesukwiwat Wusheng Fu Katerina Mastovska Eunha Hoh Natchanun Leepipatpiboon 《Journal of chromatography. A》2010,1217(16):2548-2560
This article describes the comparison of different versions of an easy, rapid and low-cost sample preparation approach for the determination of pesticide residues in fruits and vegetables by concurrent use of gas and liquid chromatography (GC and LC) coupled to mass spectrometry (MS) for detection. The sample preparation approach is known as QuEChERS, which stands for “quick, easy, cheap, effective, rugged and safe”. The three compared versions were based on the original unbuffered method, which was first published in 2003, and two interlaboratory validated versions: AOAC Official Method 2007.01, which uses acetate buffering, and European Committee for Standardization (CEN) Standard Method EN 15662, which calls for citrate buffering. LC–MS/MS and GC–MS analyses using each method were tested from 50 to 1000 ng/g in apple–blueberry sauce, peas and limes spiked with 32 representative pesticides. As expected, the results were excellent (overall average of 98% recoveries with 10% RSD) using all 3 versions, except the unbuffered method gave somewhat lower recoveries for the few pH-dependent pesticides. The different methods worked equally well for all matrices tested with equivalent amounts of matrix co-extractives measured, matrix effects on quantification and chemical noise from matrix in the chromatographic backgrounds. The acetate-buffered version gave higher and more consistent recoveries for pymetrozine than the other versions in all 3 matrices and for thiabendazole in limes. None of the versions consistently worked well for chlorothalonil, folpet or tolylfluanid in peas, but the acetate-buffered method gave better results for screening of those pesticides. Also, due to the recent shortage in acetonitrile (MeCN), ethyl acetate (EtOAc) was evaluated as a substitute solvent in the acetate-buffered QuEChERS version, but it generally led to less clean extracts and lower recoveries of pymetrozine, thiabendazole, acephate, methamidophos, omethoate and dimethoate. In summary, the acetate-buffered version of QuEChERS using MeCN exhibited advantages compared to the other tested methods in the study. 相似文献
10.
Analytical methods for the simultaneous analysis of lindane, chlorpyriphos, z-chlorfenvinphos, endosulfan A and B, 4,4'-DDE, 4,4'-TDE, acrinathrine, bromopropylate, tetradifon, coumaphos and fluvalinate in pure beeswax samples are studied. For the analysis of bleached beeswaxes, a liquid-liquid extraction with acetonitrile followed by a clean-up on polymeric cartridges is the best option in terms of recovery and precision. However, some interferences that hinder the identification and quantification of important varroacides are found when non-bleached beeswaxes are analyzed. The analysis of all compounds in the latter samples require a clean-up by coupling an ODS cartridge before the polymeric cartridge. Considerations about the influence of the matrix in the quantitative analysis by a classical external standard calibration are also made and the use of a matrix-matched calibration is advised. Recoveries resulted to be about 100% with coefficients of variation between 10% and 20% (n = 5) for concentrations of 0.5 and 5 mg/kg. 相似文献
11.
Summary A rapid and effective method is described for the extraction of organochlorine compounds (PCB 153, PCB 138, PCB 180, p,p-DDE, -HCH, -HCH, -HCH and HCB) from seal blubber and pork fat withn-hexane using a microwave technique. Heating of the non-polarn-hexane was achieved using a microwave transformer. The lipid content of the samples obtained by this extraction was identical to that by Soxhlet extraction. After separation of sample matrix and organochlorines on a silica gel column the organochlorine compounds were determined by GC-ECD. The efficiency of the method was tested with 500 mg spiked fat, extracted using various numbers of extraction cycles. Recoveries of organochlorine compounds in grey seal blubber and spiked pork fat generally exceeded 90 %. 相似文献
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The reactivity of ethylene oxide (EO) with contaminants such as potassium hydroxide (KOH), sodium hydroxide (NaOH), and ammonium hydroxide (NH4OH) was measured in this work using the automatic pressure tracking adiabatic calorimeter (APTAC). Each contaminant was investigated using three different concentration levels of around 0.10 g, 0.50 g, and 1.0 g in roughly 14 g EO. The research results show that KOH, NaOH, and NH4OH have significant effects on EO thermal stability. Reductions of onset temperatures were measured as the contaminant concentrations were increased. NH4OH caused the highest reactivity compared to the other contaminants. KOH is a contaminant that reduced the onset temperature of pure EO to near room temperature even at a low concentration. The key exotherm parameters and profiles that are critical to the design and operation of safer chemical plant processes are also provided in detail. 相似文献
14.
A sensitive and selective liquid chromatography-mass spectrometry method has been developed for the simultaneous identification and quantitation of drug substances and metabolites in rat plasma. The method combines on-line turbulent-flow chromatography, high-performance liquid chromatography and mass spectrometry. This combination is considered to be a new approach suitable for fast bio-analysis in drug discovery. Dextromethorphan, and its two metabolites, dextrorphan and 3-methoxymorphinan served as model substances. The analytes present in plasma were collected on a Cyclone column using turbulent-flow chromatography and were subsequently transferred on-line to and focused on an X-Terra MS C8 column. The analytes were eluted by a linear gradient and detected by a fast scanning mass spectrometer. The detector response was quadratic and the dynamic range was estimated to be 0.5-100 ng/ml plasma or 12.5 pg to 2.50 ng injected into the system. 相似文献
15.
Summary Air sampling of ethylene oxide on HBr-treated charcoal tubes followed by capillary GC analysis of the 2-bromoethanol produced
allows pollution control evaluation for concentrations ranging from 0.2 to 20 mgm−3. The adequacy of the method is assessed taking into account ambient temperature and relative humidity. 相似文献
16.
Jairo L. Rodrigues 《Talanta》2010,80(3):1158-162
Despite the necessity to differentiate chemical species of mercury in clinical specimens, there are a limited number of methods for this purpose. Then, this paper describes a simple method for the determination of methylmercury and inorganic mercury in blood by using liquid chromatography with inductively coupled mass spectrometry (LC-ICP-MS) and a fast sample preparation procedure. Prior to analysis, blood (250 μL) is accurately weighed into 15-mL conical tubes. Then, an extractant solution containing mercaptoethanol, l-cysteine and HCl was added to the samples following sonication for 15 min. Quantitative mercury extraction was achieved with the proposed procedure. Separation of mercury species was accomplished in less than 5 min on a C18 reverse-phase column with a mobile phase containing 0.05% (v/v) mercaptoethanol, 0.4% (m/v) l-cysteine, 0.06 mol L−1 ammonium acetate and 5% (v/v) methanol. The method detection limits were found to be 0.25 μg L−1 and 0.1 μg L−1 for inorganic mercury and methylmercury, respectively. Method accuracy is traceable to Standard Reference Material (SRM) 966 Toxic Metals in Bovine Blood from the National Institute of Standards and Technology (NIST). The proposed method was also applied to the speciation of mercury in blood samples collected from fish-eating communities and from rats exposed to thimerosal. With the proposed method there is a considerable reduction of the time of sample preparation prior to speciation of Hg by LC-ICP-MS. Finally, after the application of the proposed method, we demonstrated an interesting in vivo ethylmercury conversion to inorganic mercury. 相似文献
17.
Introducing fine polymeric filaments as the extraction medium, a miniaturized sample preparation technique for micro-column liquid chromatography (micro-LC) has been developed along with the investigation of a reproducible preparation scheme of the extraction capillary. The polymeric filaments were packed longitudinally into either a fused-silica capillary or a polyether ether ketone (PEEK) capillary of appropriate dimensions, and the extraction capillary was installed to the injection valve in micro-LC system. The number of packed filaments should be precisely counted before the packing process to make sure the reproducible preparation of the extraction capillary. With conventional stationary phase materials for open-tubular gas chromatography, polymeric coating to the surface of the filaments was also studied in order to further enhance the extraction performance and selectivity. Coated with the polymeric material suitable for the extraction of particular analyte, a dramatic improvement on the extraction power was obtained. The results suggest that the future possibility of novel tailored fibrous extraction medium with an appropriate coating on it, especially for the analysis of complex sample matrices. 相似文献
18.
Antti Leinonen Katariina Vuorensola Tiia Kuuranne Raimo A. Ketola Risto Kostiainen 《Analytica chimica acta》2006,559(2):166-172
The applicability of in-vial two-phase liquid-phase microextraction (LPME) in porous hollow polypropylene fiber was studied for the sample preparation of unconjugated anabolic steroids in urine. Four different anabolic steroids - metabolites of fluoxymesterone, 4-chlorodehydromethyltestosterone, stanozolol and danazol - were used as test compounds and methyltestosterone as an internal standard. A standard two-phase LPME method for use with liquid chromatography/mass spectrometry (LC/MS) was set up and the influence of different parameters, including the nature of organic solvent, extraction time, salting-out and temperature, on the LPME process was investigated. Taking advantage of the preliminary studies, a novel two-phase LPME method utilizing simultaneous in-fiber silylation was developed and validated for gas chromatographic/mass spectrometric (GC/MS) analysis of a danazol metabolite in urine. In all, LPME allowed a very straightforward, simple and selective way to prepare urine samples for steroid analysis, being most suitable for hydrophobic steroids. The LPME method with in-fiber derivatization for GC/MS analysis exhibited high sensitivity, repeatability and linearity and enabled simultaneous filtration, extraction, enrichment and derivatization of the analyte from urine matrix without any other steps in sample pretreatment. 相似文献
19.
Summary GC separation of pure ethanolamines as well as mixtures with ethylene glycols, obtained from a real technological process
is achived using Porapak Q coated with 15% Carbowax 20M. Symmetrical peaks, satisfactory resolution, and reasonable analysis
times are obtained. The proposed method is suitable for a convenient, correct and express routine analysis. 相似文献
20.
Sample preparation for gas chromatographic determination of halogenated volatile organic compounds in environmental and biological samples 总被引:1,自引:0,他引:1
Jakubowska N Zygmunt B Polkowska Z Zabiegała B Namieśnik J 《Journal of chromatography. A》2009,1216(3):422-441
In this review, the wide spectrum of the techniques of isolation and/or preconcentration and final determination of halogenated volatile organic compounds (HVOCs) in water, air, soil, sediment and biological fluids are presented and discussed. The techniques discussed are solvent microextraction, solid phase extraction, gas extraction (static and dynamic techniques), membrane processes and passive sampling. Also, direct techniques, such as direct aqueous injection into gas chromatography (GC) column and membrane inlet mass spectrometry, are presented. Main attention is paid to the practical application of these techniques during all HVOCs determination. 相似文献