Showing 2 results for Mass Spectrometry
H Samadikafil, M Mohebatimobarez, M Forouzandehmoghadam,
Volume 7, Issue 1 (4-2013)
Abstract
Abstract
Background and Objective: Enterococci are Gram-positive members of human gastrointestinal flora,in Dairy products and environment. they have emerged as important causes of opportunistic nosocomial infections in recent years. In this study we aimed to investigat and compare the efficiency of MALDI-TOFmass spectroscopy method through Biochemical and Molecular methods for detecting Enterococcus faecalis and Enterococcus faecium.
Materials and Methods:seventhy five clinical samples were collected for biochemical, molecular and mass spectroscopy investigations. Samples were treated with Esculin hydrolysis, Catalase, Pyrrolidonylaminopeptidase, 6.5% NaCl solution, motility, 0.04% Tellurite, L-Arabinose and Sorbitol. Using specific primesallele specific PCR was used.The samples were then analyzed by MALDI-TOF mass spectroscopy and Biotyper 3 software.
Results:Enterococcus faecium andEnterococcus faecaliswere detected in thirty and forty two samples, respectively whereas three samples showed both bacterial infections. Using biochemical analysis, two E.faecium isolates were Arabinose negative and one E. faecalis isolates was Telliurite negative. All sampleswere showed correct bands in PCR results but twoof them didn't show clear bands(on agarose gel). In mass spectroscopy analysis all strains were correctly detected and well defined.
Conclusion: According to our results, MALDI-TOF mass spectrometry in comparison with Molecular and Biochemical Methodscould be a reliable and accurate method that can easily and quickly identify and differentiate Enterococcus faecium and Enterococcus faecalisin clinical samples.
Key words:Enterococcus faecalis, Enterococcus faecium, MALDI-TOFmass spectrometry,PCR
M Sadeghi, K Naddafi, R Nabizadeh,
Volume 8, Issue 2 (7-2014)
Abstract
Abstract
Background and Objective: Perchloroethylene (PCE) is a chlorinated hydrocarbon used as a solvent in many industrial processes. In contaminated water and soil a great deal of PCE is found. This study aimed to determine the rate of decomposition of PCE occurred after advanced oxidation.
Material and Methods: In this descriptive-analytic study conducted (2011) in public health faculty of Tehran University of medical sciences, gas chromatographic was used to measure PCE and gas chromatography - mass spectrometry for intermediate products. Chemical oxidation involves ultrasonic waves, ultraviolet light and hydrogen peroxide.
Results: PCE was effectively decomposed by advanced oxidation processes. In these processes, the reaction rate was based on the equation of the first order and the rate of decomposition was proportional to the concentration. The higher was hydrogen peroxide, the more was decomposition, and the removal rate was higher at acidic PH. The intermediate products formed in the oxidation process were trichlorethylene, dihlorethylene, trichloroacetic acid, dichloroacetic acid and chloroacetic acid.
Conclusion: The toxicity of intermediate products formed by degradation of Perchloroethylene compared to its initial toxicity is low. But it is a necessity to elongate the processes for having complete destruction of intermediate compounds and preventing from their adverse effects on the environment and human health.
Keywords: Perchloroethylene, Ultrasonic, Ultraviolet, Hydrogen Peroxide, Gas Chromatography, Mass Spectrometry
