Past years, many efforts have been dedicated to the development of alternative analytical methods for the measurement of dioxins in various types of matrices. Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) are compounds that are present in samples at part-per-billion (ppb) or part-per-trillion (ppt) level. Their measurement...

The analysis of nine explosive compounds by gas chromatography tandem mass spectrometry (GC–MS/MS) using negative chemical ionization (NCI) was performed under two different conditions: first, a conventional GC separation coupled with a standard ion dissociation method in a quadrupole ion trap (QIT) was performed in segmented selected reaction monitoring mode; second, a fast GC separation on a ...

Gas chromatography mass spectrometry (GC-MS) is a widely used central analytical technology. Commercially available GC-MS systems use different types of mass analyzers such as Quadrupole, Ion Trap and/or Time of Flight, but practically all systems utilize the same Nier type electron ionization (EI) ion source and the same standard GC-MS transfer-line interface. Consequently, the various GC-MS v...

It is well known that thyroid hormone affects body composition; however, the effect of the thyroid hormone receptor beta (TRbeta)-selective thyromimetic GC-1 on this biological feature had not been demonstrated. In the current study, we compared the effects of a 6-week treatment with triiodothyronine (T3; daily injections of 3 or 6 microg/100 g body weight) or GC-1 (equimolar doses) on differen...

Although mass spectrometry has been studied extensively in the past 50 years for analysis of petroleum and other fossil fuels, comprehensive characterization of total petroleum composition across a wide boiling range remains a challenge. In this work, we report our efforts in combining GC separation, field Ionization, and time-of-flight high-resolution mass spectrometry (GC-FI-TOF HRMS) for det...

The majority of atmospheric measurements of volatile organic compounds (VOCs) are usually limited to a small range, either in volatility or time resolution. A combined heart-cut gas chromatography (GC) with comprehensive two-dimensional GC (GC×GC) instrument was developed, specifically to increase the number of VOCs analysed using a single instrument. The system uses valve based modulation and ...

Sample Types LC/MS systems facilitate the analysis of samples that traditionally have been difficult to analyze. Despite the power and usefulness of gas chromatography/mass spectrometry (GC/MS), many compounds are impossible to analyze with GC/MS. LC/MS significantly expands the effective analytical use of mass spectrometry to a much larger number of organic compounds. Gas chromatography and GC...

A single fraction of essential oil can often contain hundreds of compounds. Despite of the technical improvements and the enhanced selectivity currently offered by the state-of-the-art gas chromatography (GC) and mass spectrometry (MS) instruments, the complexity of essential oils is frequently underestimated. Comprehensive two-dimensional GC coupled to time-of-flight MS (GC×GC-TOFMS) was used ...

A quantitative analysis of the individual compounds in tobacco essential oils is performed by comprehensive two-dimensional gas chromatography (GC x GC) combined with flame ionization detector (FID). A time-of-flight mass spectrometer (TOF/MS) was coupled to GC x GC for the identification of the resolved peaks. The response of a flame ionization detector to different compound classes was calibr...

In order to determine aqueous extract effects of cool-season turfgrass mixture clipping on germination and seedling growth of four weed species, laboratory and outdoor pot experiments were done at the experimental laboratory and greenhouse of the Doroud Parks and Landscape Organization, located in Doroud, Lorestan, Iran. The first factor was the concentration of sport turfgrass clipping extract...