SciCombinator

Discover the most talked about and latest scientific content & concepts.

Journal: Rapid communications in mass spectrometry : RCM

28

Direct analysis in real time (DART) is a novel ionization technique that has been demonstrated in numerous applications as a useful tool for fast and convenient mass spectrometry (MS)-based analysis of complex samples. In this study, the feasibility of DART ionization coupled to a high-resolution mass spectrometer utilizing an orbitrap mass analyzer (orbitrap MS) for high-throughput analysis of antiparasitic veterinary drugs was explored.

Concepts: Mass spectrometry, Ion source, Measuring instruments, Fast atom bombardment, Fourier transform ion cyclotron resonance, Ionization, DART ion source

28

Herein we describe a strong matrix effect observed in the matrix-assisted laser desorption/ionization time-of-flight (MALDI-ToF) mass spectra of silylated glycerol alkoxylates and manifested in the loss of the silyl groups in the presence of carboxyl-containing matrices.

Concepts: Spectroscopy, Mass spectrometry, The Loss

28

Probe electrospray ionization (PESI) is a recently developed method that uses a sharp solid needle as electrospray emitter and the sample is loaded to the needle tip by repetitive movement of the needle probe. This method has been previously used for the analysis of sample with high salt concentration and real-world samples without sample pretreatment. Although PESI is also applicable to aqueous solution, the ion signal stability and reproducibility were not satisfactory due to the spontaneous occurrence of corona discharge taking place on the metallic needle tip.

Concepts: Concentration, Chemical properties, Chemistry, Solid, 1980s music groups, Ion source, Solutions, Aqueous solution

28

This paper reports the development of arrays of capillary-based low-temperature plasma (LTP) probes for direct sample analysis. These probe arrays allow a higher surface area to be analyzed, increasing the throughput in large sample analysis. Validation of these arrays was performed on illicit, cathinone-based drugs marketed as ‘bath salts’.

Concepts: Mass spectrometry, Magnesium sulfate, Area, Surface area, Space probe, Bath salts

28

There is interest in extending bottom-up proteomics to the smallest possible sample size. We investigated the performance of two modern mass spectrometers for the analysis of samples ranging from 1 ng to 1 µg of RAW 264.7 cell lysate digests.

Concepts: Sample, Protein, Cell biology, Proteomics, Matrix-assisted laser desorption/ionization, Top-down proteomics, Shotgun proteomics, Bottom-up proteomics

28

Agarwood is the resinous material harvested from threatened Aquilaria species. We investigated how many protonated 2-(2-phenylethyl)chromone ions were sufficient to make an accurate identification of agarwood. Analysis of 125 reference samples was carried out by direct analysis in real time time-of-flight mass spectrometry (DART-TOFMS). The identification criteria developed were applied to commercial samples.

Concepts: Mass spectrometry, Calculus, Ion source, Time-of-flight, Agarwood, Aquilaria, Aquilaria malaccensis

28

Isobaric labeling strategies (e.g. iTRAQ or TMT) are commonly applied in tandem mass spectrometric (MS/MS) level quantitative proteomics. However, we frequently observed missing isotope reporter ion signals in a large-scale liquid chromatography/matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometric (LC/MALDI-TOF/TOF) quantitative proteomics experiment. To understand this issue, we systematically investigated the processing of MS/MS spectra into peak lists prior to peptide identification and quantification.

Concepts: Scientific method, Mass spectrometry, Research, Proteomics, Tandem mass spectrometry, Tandem mass tags, Quantitative proteomics, SILAC

28

Secondary ion mass spectrometry (SIMS) is an important technique for the characterization of proteins at surfaces. However, interpretation of the mass spectra is complicated owing to confusion with peaks from contaminants and the substrate which is further compounded by complex fragmentation mechanisms. We test a new development of the G-SIMS method called the g-ogram to separate out spectral components without a priori information about which peaks to include in the analysis and which peaks relate to each component.

Concepts: Cell, Enzyme, Mass spectrometry, Peptide, In-gel digestion, Ion source, Peptide sequence, Secondary ion mass spectrometry

27

The burgeoning field of ‘clumped isotope’ paleothermometry, which has broad applications in geosciences, depends almost entirely on measurements made on two types of mass spectrometer with the same ion source design. Demonstration that these measurements can be carried out on a retrofitted mass spectrometer with a different type of ion source is important to the growing community of geoscientists considering employing this technique.

Concepts: Mass spectrometry, Atom, Ion source, Isotope, Special relativity, Isotopes, Isotopologue, Isotope ratio mass spectrometry

27

Anabolic agents have been top-ranked for many years among statistics of adverse analytical findings compiled by the World Anti-Doping Agency (WADA). Besides archetypical anabolic-androgenic steroids (AAS), alternative substances with similar effects concerning bone and muscle anabolism have been therapeutically pursued. A prominent emerging class of drugs is the chemically heterogeneous group of selective androgen receptor modulators (SARMs), some of which have been detected in doping control samples between 2009 and 2012 despite missing clinical approval.

Concepts: Metabolism, Testosterone, Androgen, Steroid, Anabolic steroid, Anabolism, Selective androgen receptor modulator, World Anti-Doping Agency