Semi-quantitative analysis of contaminants in soils by direct analysis in real time (DART) mass spectrometry.

Rationale: Cleaning up contaminated sites is a goal of the U.S. Environmental Protection Agency (EPA).

Evaluation of splenectomy as a risk factor for gastric dilatation-volvulus.

Objective: To evaluate whether dogs undergoing splenectomy had an increased risk of gastric dilatation-volvulus (GDV), compared with a control group of dogs undergoing enterotomy.

Design: Retrospective case-control study.

Animals: 219 dogs that underwent splenectomy for reasons other than splenic torsion (splenectomy group; n = 172) or enterotomy (control group; 47) without concurrent gastropexy.

Detection of illicit drugs on surfaces using direct analysis in real time (DART) time-of-flight mass spectrometry.

Methamphetamine (meth) from meth syntheses or habitual meth smoking deposited on household surfaces poses human health hazards. The U.S.

Mass spectrometric identification of an azobenzene derivative produced by smectite-catalyzed conversion of 3-amino-4-hydroxyphenylarsonic acid.

The compound 3-amino-4-hydroxyphenylarsonic acid (3-amino-HPAA) reacts with smectite to form a soluble azobenzene arsonic acid compound. This reaction is of particular interest because it provides a possible mechanism for the formation of a new type of arsenic compound in natural water systems. 3-Amino-HPAA is a degradation product excreted by chickens that are fed rations amended with roxarsone.

Automated determination of precursor ion, product ion, and neutral loss compositions and deconvolution of composite mass spectra using ion correlation based on exact masses and relative isotopic abundances.

After an accidental, deliberate, or weather-related dispersion of chemicals (dispersive event), rapid determination of elemental compositions of ions in mass spectra is essential for tentatively identifying compounds. A direct analysis in real time (DART)ion source interfaced to a JEOL AccuTOFmass spectrometer provided exact masses accurate to within 2 mDa for most ions in full scan mass spectra and relative isotopic abundances (RIAs) accurate to within 15-20% for abundant isotopic ions. To speed determination of the correct composition for precursor ions and most product ions and neutral losses, a three-part software suite was developed.

Purification, identification and activity of phomodione, a furandione from an endophytic Phoma species.

Phomodione, [(4aS(*),9bR(*))-2,6-diacetyl-7-hydroxy-4a,9-dimethoxy-8,9b-dimethyl-4a.9b-dihydrodibenzo[b,d]furan-1,3(2H,4H)-dione], an usnic acid derivative, was isolated from culture broth of a Phoma species, discovered as an endophyte on a Guinea plant (Saurauia scaberrinae). It was identified using NMR, X-ray crystallography, high resolution mass spectrometry, as well as infrared and Raman spectroscopy.

Determination of ion and neutral loss compositions and deconvolution of product ion mass spectra using an orthogonal acceleration time-of-flight mass spectrometer and an ion correlation program.

Exact masses of monoisotopic ions, and the relative isotopic abundances (RIAs) of ions greater in mass by 1 and 2 Da than the monoisotopic ion, are independent and complementary physical properties useful for distinguishing among elemental compositions of ions possible for a given nominal mass. Using these properties to determine elemental compositions of product ions and neutral losses increases the masses of precursor ions for which unique compositions can be determined. Compositions of the precursor ion, product ion, and neutral loss aid mass spectral interpretation and guide modest chemical literature searches for candidate standards to be obtained for confirmation of tentative compound identifications.

Using a triple-quadrupole mass spectrometer in accurate mass mode and an ion correlation program to identify compounds.

Atomic masses and isotopic abundances are independent and complementary properties for discriminating among ion compositions. The number of possible ion compositions is greatly reduced by accurately measuring exact masses of monoisotopic ions and the relative isotopic abundances (RIAs) of the ions greater in mass by +1 Da and +2 Da. When both properties are measured, a mass error limit of 6-10 mDa (< 31 ppm at 320 Da) and an RIA error limit of 10% are generally adequate for determining unique ion compositions for precursor and fragment ions produced from small molecules (less than 320 Da in this study).

Utility of three types of mass spectrometers for determining elemental compositions of ions formed from chromatographically separated compounds.

Concentration factors of 1000 and more reveal dozens of compounds in extracts of water supplies. Library mass spectra for most of these compounds are not available, and alternative means of identification are needed. Determination of the elemental compositions of the ions in mass spectra makes feasible searches of commercial and chemical literature that often lead to compound identification.