in this study, a simple and reliable method by gas chromatograph–mass spectrometry (gc–ms) was developed for the fast and regular identification of 3, 4-mdma impurities in ecstasy tablets. in so doing, 8 samples of impurities were extracted by diethyl ether under alkaline condition and then analyzed by gc–ms. the results revealed high mdma levels ranging from 37.6% to 57.7%. the gc-ms method sh...

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...

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...

The most effective methods of analysis of organic compounds in biological fluids are coupled chromatographic techniques. Capillary gas chromatography/mass spectrometry (GC-MS) allows the most efficient separation, identification and quantification of volatile metabolites in biological fluids. Liquid chromatography-mass spectrometry (LC-MS) is especially suitable for the analysis of non-volatile...

The review describes on-line derivatization/degradation methods employed in mass spectrometry to solve some structural and analytical problems. Advantages and applications of various positions of reaction systems connected mainly to a mass spectrometer or a gas chromatograph/mass spectrometer are considered. Among these are reaction systems connected directly to the mass spectrometer (reaction ...

The complex nature of botanicals and essential oils makes it difficult to identify all of the constituents by gas chromatography/mass spectrometry (GC/MS) alone. In this paper, automated sequential, multidimensional gas chromatography/mass spectrometry (GC-GC/MS) was used to obtain a matrix-specific, retention time/mass spectrometry library of 190 juniper berry oil compounds. GC/MS analysis on ...

Oral fluids are being used as an alternative matrix to urine for drug testing. Oral fluid is considered to be less invasive and much more difficult to adulterate than urine samples. Samples of oral fluid are typically screened by an ELISA immunoassay method. Those found to be positive must be further analyzed with a mass spectrometry confirmation technique. The confirmation technique must be ab...

Location of the double-bond position of monounsaturated fatty acids of Aerococcus viridans was accomplished by combined gas chromatography (GC)-mass spectrometry analysis of dimethyl disulfide (DMDS) derivatives. The monoenoic fatty acids from whole bacterial cells were converted to methyl esters and then to DMDS adducts and analyzed by capillary GC-mass spectrometry. The mass spectra of DMDS a...

Peak alignment is a critical procedure in mass spectrometry-based biomarker discovery in metabolomics. One of peak alignment approaches to comprehensive two-dimensional gas chromatography mass spectrometry (GC×GC-MS) data is peak matching-based alignment. A key to the peak matching-based alignment is the calculation of mass spectral similarity scores. Various mass spectral similarity measures h...