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Triethyltin, tributyltin, diphenyltin and triphenyltin were selected as model compounds. The method is based on in situ ethylation and simultaneous headspace-solid-phase microextraction (HS-SPME) and gas chromatographic-mass spectrometry analysis (GC–MS). The extraction procedure was optimized studying some variables such as reaction time, salinity, sample volume and headspace volume. SPME–GC–MS and...
A critical comparison of methods for correcting severely retention time shifted gas chromatography–mass spectrometry (GC–MS) data is presented. The method reported herein is an adaptation to the piecewise alignment algorithm to quickly align severely shifted one-dimensional (1D) total ion current (TIC) data, then applying these shifts to broadly align all mass channels throughout the separation, referred...
An accelerated solvent extraction (ASE) procedure has been developed as a pretreatment method for chemical fingerprinting of volatile and semi-volatile components in cut tobacco. The ASE extraction conditions including temperature, operation pressure and extraction cycles were optimized to maximize extraction yield. The method was validated with repeatability, recovery and linearity. Compared with...
An automated dynamic closed chamber system for CO 2 sampling and analysis was developed for the measurement of soil respiration under laboratory conditions. The system is composed by a gas chromatograph linked to a fully computerised sampling system composed by 16 sample jars and 2 multiposition valves. Besides CO 2 , the system can automatically and simultaneously measure CH 4...
The analytical characteristics of several new brominated flame retardants (BFRs) were investigated. Spiked dust extracts were used to compare the relative stability and recovery of new BFRs during three clean-up procedures on silica, acidified silica and Florisil. The behaviour of new BFRs in two ionization sources of the mass spectrometer (MS), electron impact (EI) and electron capture negative ionization...
In this study a new dispersive liquid–liquid microextraction (DLLME) method is presented on the basis of a safe organic solvent, octanol, which is lighter than water. The proposed method is used for the extraction and pre-concentration of some preservatives including methyl paraben (Mep), ethyl paraben (Etp) and propyl paraben (Prp) from different matrices. The extracted compounds are monitored by...
A novel, single step method for the determination of seven ink photo-initiators in carton packed milk samples is described. Solid-phase microextraction (SPME) and gas chromatography (GC), combined with mass spectrometry (MS), were used as sample preparation and determination techniques, respectively. Parameters affecting the performance of the microextraction process were thoroughly evaluated using...
Arsenic is a metalloid well known to be potentially toxic depending of its species. Lipid-soluble arsenicals (arsenolipids) are present in a wide range of biological samples in which they could play a role in the biosynthesis of organoarsenic compounds from inorganic arsenic compounds. Arsenolipids have recently attracted considerable interest. In order to gain deeper insights into the impact of arsenolipids...
A new method was developed for simultaneous determination of cypermethrin and permethrin residues in pear juice with ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME) and gas chromatography-flame ionization detection (GC-FID). 3.5mL of methanol (dispersant) and 30μL of C 2 Cl 4 (extractant) were injected into 5.0mL of pear juice sample and then emulsified by ultrasound...
Use of pesticides has turned out to be an obligatory input to agriculture and public health. Versatile use of pesticides had resulted in contamination of all basic necessities of life, i.e. air, water and food. Among various pesticides, organophosphorus pesticides (OPPs), derivative of phosphoric acid, are the most extensively used insecticides or acaricides in many crops. Due to low persistency and...
A rapid sampling technique for the analysis of beer aroma compounds is described. The headspace (10ml) is passed through the microcolumn filled with 5mg of Tenax TA and thermally desorbed in a modified GC inlet (modification is described). Eight compounds (from acetaldehyde to 2-phenylethanol) in four beer samples were analyzed. The correlation coefficients (r 2 ), repeatability (RSD) and...
Li 2 O–ZrO 2 –BaO–SiO 2 glass fibers were produced and their surfaces were coated with zinc oxide. The fibers’ surface morphology was examined by scanning electron microscopy and the zinc oxide layer was characterized by mapping the K α and L α lines of zinc by energy dispersive X-ray spectroscopy. The results indicated that a homogeneous and porous layer of...
Quantitative structure–retention relationship (QSRR) models correlating the retention times of fatty acid methyl esters in high resolution capillary gas chromatography and their structures were developed based on non-linear and linear modeling methods. Genetic algorithm (GA) was used for the selection of the variables that resulted in the best-fitted models. Gravitational index (G2), number of cis...
A fast method that can be used to classify unknown jet fuel types or detect possible property changes in jet fuel physical properties is of paramount interest to national defense and the airline industries. While fast gas chromatography (GC) has been used with conventional mass spectrometry (MS) to study jet fuels, fast GC was combined with fast scanning MS and used to classify jet fuels into lot...
A novel solid-phase microextraction (SPME) fiber coated with multiwalled carbon nanotubes/polypyrrole (MWCNTs/Ppy) was prepared with an electrochemical method and used for the extraction of pyrethroids in natural water samples. The results showed that the MWCNTs/Ppy coated fiber had high organic stability, and remarkable acid and alkali resistance. In addition, the MWCNTs/Ppy coated fiber was more...
A new ionic liquid (IL) based solid-phase microextraction (SPME) fiber was investigated and used for headspace (HS) extraction of methyl tert-butyl ether (MTBE) in a gasoline sample. Using the new IL coated HS-SPME fiber with the combination of gas chromatography–flame ionization detection (GC–FID); sub-to-low μgL −1 concentrations of MTBE were detected. Four different ILs including 1-butyl-3-methylimidazolium...
There is a need to develop sensitive and accurate analytical methods for determining deoxynivalenol (DON), HT-2 toxin and T-2 toxin in paprika to properly assess the relevant risk of human exposure. An optimized analytical method for determination of HT-2 toxin and T-2 toxin using capillary gas chromatography with electron capture detection and another method for determination of DON by liquid chromatography–mass...
A new multiresidue method has been developed and validated for the simultaneous extraction of more than two hundred pesticides, including non-polar and polar pesticides (carbamates, organochlorine, organophosphorous, pyrethroids, herbicides and insecticides) in urine at trace levels by gas and ultra high pressure liquid chromatography coupled to ion trap and triple quadrupole mass spectrometry, respectively...
A novel sample preparation technique, the microextraction method based on a dynamic single drop in a narrow-bore tube, coupled with gas chromatography–flame ionization detection (GC–FID) is presented in this paper. The most important features of this method are simplicity and high enrichment factors. In this method, a microdrop of an extraction solvent assisted by an air bubble was repeatedly passed...
Gas chromatography coupled to time-of-flight mass spectrometry (GC–TOF MS) has been applied to characterize the organic pollution pattern of marine salt samples collected in saltworks from the Spanish Mediterranean coast. After dissolving the samples in water, a solid-phase extraction was applied reaching with a 250-preconcentration factor. The screening methodology allowed the detection of sample...
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