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G E Collins

Publications and source records attributed to G E Collins.

8 recordsLinked to original sources
PubMed2001

Separation of uranium(VI) and transition metal ions with 4-(2-thiazolylazo)resorcinol by capillary electrophoresis.

A capillary electrophoresis method utilizing 4-(2-thiazolylazo)resorcinol (TAR) was developed to separate uranium, cobalt, cadmium, nickel, titanium and copper metal ions. TAR was chosen as the visible absorbing chelating ligand because of its ability to form stable complexes with a wide variety of metals. Several parameters that included pH, electrophoretic run buffer concentration, buffer type and the influence of chelating ligand in the electrophoretic run buffer were examined to determine the best separating conditions. Optimum separation of the six metal chelates was achieved in a 15 mM Na2B4O7-NaH2PO4, pH 8.3 buffer containing 0.1 mM TAR. Method validation included injection and method precision studies as well as detection limit and linear dynamic range determination. High-ppb to low-ppm (w/w ratio) detection limits were achieved with linear dynamic ranges between 0.1 and 75 ppm.

Azo Compounds↗
PubMed2001

Microchip separations of transition metal ions via LED absorbance detection of their PAR complexes.

Micellar electrokinetic chromatography was utilized in the electrophoretic separation of seven transition metal ions, colorimetrically complexed by 4-(2-pyridylazo)resorcinol (PAR) on a glass capillary electrophoresis microchip. Detection of the PAR metal chelates was demonstrated using a green light emitting diode (540 nm) and a miniature photomultiplier tube. Parameters investigated included the effect of buffer type, pH and surfactant concentration (sodium dodecyl sulfate, SDS) on the separation efficiency. The optimally determined background electrolyte contained 10 mM ammonium phosphate buffer (pH 7.5), 1 mM PAR to prevent kinetic lability problems and 75 mM SDS for enhanced resolution. The separation of seven transition metal ions, Co2+, V3+, Ni2+, Cu2+, Fe2+, Mn2+ and Cd2+, was achievable in under 65 s, with the resolution of each metal ion in excess of 1.60. Detection limits obtained ranged from 400 ppb for Ni2+ to 1.2 ppm for Mn2+.

Chromatography, Micellar Electrokinetic Capillary↗
PubMed1994

P300 from a single auditory stimulus.

The P3(00) event-related brain potential (ERP) was elicited with auditory stimuli to compare 2 different discrimination tasks. The oddball paradigm presented both target and standard tones; the single-stimulus paradigm presented a target but no standard tone stimulus. Experiment 1 manipulated target stimulus probability (0.20, 0.50, 0.80) and produced highly similar P3 amplitude and latency results across probability levels for each paradigm. Experiment 2 factorially varied inter-stimulus interval (2 sec, 6 sec) and target stimulus probability (0.20, 0.80). P3 amplitude and latency were highly similar for both the oddball and single-stimulus procedures across all conditions.

Acoustic Stimulation↗
PubMed1979

Preparation of cardioplegic solutions.

The manufacturing methods and quality control procedures for two cardioplegic solutions are described. Procedures for preparing individual bottles or batches of two cardioplegic solutions (one with and one without albumin) and a carbonate-bicarbonate buffer solution are described. Final buffered cardioplegic solutions with albumin are stable for seven days. Cardioplegic solutions without albumin and buffer are stable for 30 days. The chemical and physiological factors affecting the content and preparation of cardioplegic solutions used during intracardiac surgery are reviewed. Because consistency is attained more readily, and because control procedures, including quarantining, are applied more readily to batch production of cardioplegic solutions, it is advised that this method be used.

Albumins↗