Search results for "MASS SPECTROMETRY"
showing 10 items of 2544 documents
Preparation by radio-frequency magnetron co-sputtering and characterization of thin films of lanthanum–strontium ferromanganites
2005
Abstract (La 0.8 Sr 0.2 )(Mn 1 − y Fe y )O 3 ± δ films with y = 0, 0.2, 0.5, 0.8 and 1, a few hundred nanometers thick, were deposited onto polycrystalline yttria-stabilized zirconia YSZ by a magnetron co-sputtering technique using individual targets of La 0.8 Sr 0.2 MnO 3 and La 0.8 Sr 0.2 FeO 3 . The deposition parameters, substrate temperature and gas pressure, were studied by scanning electron microscopy, energy dispersive X-ray spectrometry, X-ray diffraction and interferential microscopy for their effects on the morphological, chemical, topographic and crystallographic properties of films and YSZ-film interfaces. (La 0.8 Sr 0.2 )(Mn 1 − y Fe y )O 3 ± δ thin films were found to be …
Detection of the synthetic drug 4-fluoroamphetamine (4-FA) in serum and urine.
2010
Abstract 4-Fluoroamphetamine (4-FA) was detected in the blood and urine of two individuals suspected for driving under the influence (DUI). The test for amphetamines in urine subjected to immunoassay screening using the CEDIA DAU assay proved positive. Further investigations revealed a 4-FA cross-reactivity of about 6% in the CEDIA amphetamine assay. 4-FA was qualitatively detected in a general unknown screening for drugs using GC/MS in full scan mode. No other drugs or fluorinated phenethylamines were detected. A validated GC/MS method was established in SIM mode for serum analysis of 4-FA with a limit of detection (LOD) of 1 ng/mL and a lower limit of quantification (LLOQ) of 5 ng/mL. Int…
Analysis of pesticides in fruits by pressurized liquid extraction and liquid chromatography-ion trap-triple stage mass spectrometry.
2005
A multi-residue method using pressurized liquid extraction (PLE) and liquid chromatography-quadrupole ion trap-triple stage mass spectrometry (LC-IT-MS(3)) has been developed for determining trace levels of pesticides in fruits. The selected pesticides can be distinguished in: benzimidazoles and azoles, organophosphorus, carbamates, neonicotinoids, and acaricides. PLE has been optimized to extract these pesticide residues from oranges and peaches by studying the effect of experimental variables on PLE efficiency. Samples were extracted at high temperature and pressure (75 degrees C and 1500psi) using ethyl acetate as extraction solvent and acidic alumina as drying agent. The recoveries obta…
SANIST: optimization of a technology for compound identification based on the European Union directive with applications in forensic, pharmaceutical …
2016
Electrospray Ionization and collision induced dissociation tandem mass spectrometry are usually employed to obtain compound identification through a mass spectra match. Different algorithms have been developed for this purpose (for example the nist match algorithm). These approaches compare the tandem mass spectra of the unknown analyte with the tandem mass spectra spectra of known compounds inserted in a database. The compounds are usually identified on the basis of spectral match value associated with a probability of recognition. However, this approach is not usually applied to multiple reaction monitoring transition spectra achieved by means of triple quadrupole apparatus, mainly due to…
Proteomic analysis of Kveim reagent identifies targets of cellular immunity in sarcoidosis
2017
Background Kveim-reagent (Kv) skin testing was a historical method of diagnosing sarcoidosis. Intradermal injection of treated sarcoidosis spleen tissue resulted in a granuloma response at injection site by 4–6 weeks. Previous work indicates proteins as the possible trigger of this reaction. We aimed to identify Kv-specific proteins and characterise the ex vivo response of Peripheral Blood Mononuclear Cells (PBMCs) from sarcoidosis, tuberculosis and healthy control patients when stimulated with both Kv and selected Kv-specific proteins. Methods Kv extracts were separated by 1D-SDS-PAGE and 2D-DIGE and then underwent mass spectrometric analysis for protein identification. Sarcoidosis and con…
Importance of Propionibacterium acnes hemolytic activity in human intervertebral discs: A microbiological study
2018
Most patients with chronic lower back pain (CLBP) exhibit degenerative disc disease. Disc specimens obtained during initial therapeutic discectomies are often infected/colonized with Propionibacterium acnes, a Gram-positive commensal of the human skin. Although pain associated with infection is typically ascribed to the body's inflammatory response, the Gram-positive bacterium Staphylococcus aureus was recently observed to directly activate nociceptors by secreting pore-forming α-hemolysins that disrupt neuronal cell membranes. The hemolytic activity of P. acnes in cultured disc specimens obtained during routine therapeutic discectomies was assessed through incubation on sheep-blood agar. T…
The characterization of the capability of a balance
1996
A survey is given on important standardized definitions by which the capability of balances may be characterized. Some modifications are proposed with regard to the use of mass sensors for the continuous determination of mass variations. An important supplement is the ‘relative resolution’ introduced by Jenemann. Optimum values are presented.
Analytical methods to determine cocaine contamination of banknotes from around the world
2008
Abstract The presence of cocaine in a significant number of UK pounds (Xxxx), Euros (€) and North American banknotes ($) in general circulation requires appropriate tools to do determinations. This article discusses the-state-of-the-art in the analysis of cocaine on banknotes. We summarize the usual extraction methods of currency samples and compare them, especially with respect to avoiding sample damage. We critically discuss analytical methods, namely gas chromatography (GC) and liquid chromatography (LC), capillary electrophoresis (CE), immunoassay, thermal desorption tandem mass spectrometry (TD-MS2) and ion-mobility spectrometry (IMS). We also review cocaine levels on banknotes around …
Improved comparison of bar P and P charge-to-mass ratios
1995
The measured ratio of charge-to-mass ratios for the antiproton and proton is 1.000 000 001 5 ± 0.000 000 001 1. This 1 part in 109 comparison (1 ppb) is possible because a single or p is now directly observed while trapped in an open access Penning trap. The comparison is the most accurate mass spectrometry of particles with opposite charge and is the most sensitive test of CPT invariance for a baryon system. It is 40 times more accurate than our earlier comparison with many trapped antiprotons and protons, and is more than 45 000 times more accurate than earlier comparisons made with other techniques.
Identification of Lactobacilli from Deep Carious Lesions by Means of Species-Specific PCR and MALDI-TOF Mass Spectrometry
2014
SUMMARY Background: The aim of the present study was to compare MALDI-TOF results for the identification of 87 lactobacilli, isolated from soft or hard carious dentin from 70 first molars of 7- to 8-year-old children with those obtained by species-specific PCR. Methods: The 87 isolates were analyzed by MALDI-TOF MS (Microflex LT, MALDI Biotyper 3.0, Bruker Daltonik, Bremen, Germany), using a reference data base of 4110 strains including > 90 lactobacillus species. For the identification with species-specific PCR, oligonucleotide primers (16S rRNA) specific for L. casei, L. paracasei, L. rhamnosus, L. gasseri, L. plantarum, and L. acidophilus were used; type strains served as controls. The P…