Biomedical subjects
S D Richardson
Publications and source records attributed to S D Richardson.
Mass spectrometry in environmental sciences.
Explore the source record for details and available documents.
Environmental mass spectrometry.
Explore the source record for details and available documents.
Identification of reactive dyes in spent dyebaths and wastewater by capillary electrophoresis-mass spectrometry.
Capillary electrophoresis with diode array detection and mass spectrometry combined with solid-phase extraction were employed for the identification of reactive vinylsulfone and chlorotriazine dyes and their hydrolysis products in spent dyebaths and raw and treated wastewater. Recoveries of dyes from treated wastewater as their tetrabutylammonium ion-pairs using C18 reversed-phase cartridges ranged from 81 to 121%. Detection limits in sewage effluent of the different dyes and hydrolysis products ranged from 23 to 42 microg/l. The method was successfully applied to the detection of the hydrolysis products of five reactive dyes in influents and effluents of a municipal wastewater treatment plant receiving dyehouse effluents.
Analysis of anionic metallized azo and formazan dyes by capillary electrophoresis-mass spectrometry.
Capillary electrophoresis-mass spectrometry was applied to the separation of several anionic dyes containing copper(II), chromium(III), or cobalt(III) as part of the dye molecule. The dyes were separated using a 110 cm x 50 microm uncoated fused-silica capillary and a 5 mM ammonium acetate buffer (pH 9) containing 40% acetonitrile. Excellent separation efficiencies (N = 500,000 plates/column) and low detection limits of 20-50 pg (selected ion monitoring, S/N = 10) were achieved. Mass spectra were acquired at different cone voltages. At low cone voltages (low collision energies), sensitivity was maximized and the mass spectra contained only signals of the (multiply charged) molecular ions and low levels of sodium ion and proton adducts. At higher cone voltages, the 2:1 (ligand:metal) chromium and cobalt dyes showed losses of one of the two dye ligands, accompanied by a reduction of the metal. The copper dyes showed signals due to loss of SO2 and SO3-, but no release of metal. Azo cleavage, otherwise typical of azo dyes, was not observed with the metallized dyes.
Water analysis.
Explore the source record for details and available documents.
Effect of prenatal exposure to phenobarbital on the development of monoamine oxidase and glucocorticoids.
1. Fetal exposure to phenobarbital (PB, 30 mg/kg) 2-5 days prior to parturition was conducted in Sprague-Dawley rats. The fetal exposure to PB resulted in: (a) Significant increase (P less than 0.01) in body wt at 23 and 42 days of age; (b) Significant increase (P less than 0.01) in brain wt at all ages studied; (c) Significant decline (P less than 0.05) in liver monoamine oxidase at day 13 of age; (d) Significant (P less than 0.05) increase in plasma corticosterone levels at days 23 and 42.
Identification of drinking water contaminants in the course of a childhood cancer investigation in Toms River, New Jersey.
Using a combination of gas chromatography/mass spectrometry (GC/MS) and gas chromatography/infrared spectroscopy (GC/IR) spectroscopic techniques, chemical contaminants and their hydrolysis products were identified in well water sampled in connection with a suspected childhood cancer cluster located in Dover Township, Ocean County, New Jersey. The drinking water contamination resulted from the leaching of industrial waste chemicals from drums that were disposed of at the site known as Reich Farm. Contaminants identified include dinitrile-tetralin compounds, known as 'trimers,' that are by-products of a polymerization process widely used by several polymer manufactures during the 1970s and 1980s (and still used today). Also identified were 'trimer' hydrolysis products, formed by the hydrolysis of their nitrile groups to amides. These industrial contaminants were not present in any of the mass or IR spectral library databases, and their identification required unconventional spectroscopic methods (including high resolution mass spectrometry, chemical ionization mass spectrometry, and IR spectroscopy), along with scientific reasoning and interpretation. It is currently not known whether these chemical contaminants are responsible for the childhood cancers observed in this area.