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T L Chester

Publications and source records attributed to T L Chester.

5 recordsLinked to original sources
PubMed2001

Techniques for increasing the throughput of flow injection mass spectrometry.

Improvements to the design and operation of a Gilson 215 multiprobe liquid-handling system have resulted in a significant increase in the throughput for flow injection molecular weight characterization of combinatorial chemistry libraries. The rapid injection sequence, and subsequent increased sample throughput, is effected by directing the entire mobile-phase flow through each of the injection loops sequentially while isolating or "dead-ending" the remaining nonactive loops. This mode of operation was accomplished by incorporating column-switching valves prior to and following the set of eight parallel injectors. Analysis rates are achieved without sacrificing the integrity of the flow injection peak profile as baseline resolution is maintained for all samples. Using this system, the total analysis time for a 96-well microtiter plate has been reduced to approximately 5 min.

Journal Article↗
PubMed1995

Estimation of liquid-vapor critical loci for CO2-solvent mixtures using a peak-shape method.

Critical-mixture curves for 13 CO2-solvent binary mixtures were estimated using the peak-shape method. Mixture critical points were determined within 1 degrees C and 1 atm. The results for CO2-toluene and CO2-methanol were compared to previously reported data from high-pressure view cell studies. No more than a 3% difference was observed in the data generated by the two different techniques. A few abnormalities encountered while using the peak-shape method are also discussed.

Carbon Dioxide↗
PubMed1981

Determination of (dichloromethylene) diphosphonate in physiological fluids by ion-exchange chromatography with phosphorus-selective detection.

An analytical method is presented for the determination of (dichloromethylene) disphosphonate (Cl2MDP) in serum and urine. Cl2MDP is isolated from biological samples by adsorption onto precipitated calcium phosphate. Orthophosphate is separated from Cl2MDP by anion-exchange chromatography using AG 1-X8 resin. Detection is accomplished on-line using a flame photometric detector. Potentially interfering condensed phosphates are removed by acid hydrolysis. Sample handling losses are corrected by monitoring the recovery of a [14C] Cl2MDP spike added to the samples. Determinations of Cl2MDP to concentrations as low as 2 mumol/l are possible. Extension of the method to determine other diphosphonates is discussed.

Chromatography, Ion Exchange↗