An oscillating plasma glow discharge detector for gas
chromatography is used to obtain fingerprint information
about an analyte by combining both the average cell
current and oscillation frequency signals. Five homologs
each of the n-alkanes, 1-alkenes, 1-alkynes, 2-ketones and
aldehydes are studied. Although triplicate determinations
had some scatter due to...
A double-beam photometer was designed and built employing photon counting to give a direct digital readout. It was evaluated as an analytical instrument with special emphasis on pulse recovery time, pulse interaction and instrument settings. An equation is developed to explain pulse interaction in event counting systems.
The temporal and spatial characteristics of a laser microprobe plume were investigated using the spectroscopic methods of emission, absorption and fluorescence. The plume was produced by rapid vaporization of a small quantity (1 μg) of a solid sample using a focussed pulsed dye laser (110 MW/cm²). For absorption and fluorescence...
An atmospheric pressure argon glow discharge is shown
to detect trace levels of carbohydrates in aqueous flowing
systems, using either of two glow discharge solution
interface configurations. The first configuration consists
of an oscillating glow discharge sustained between a flowing
aqueous cathode and platinum anode. Picomole and micromolar
mass and...
The use of gas jets in a sputtering cell makes this direct sampling method practical for atomic absorption and mass spectrometry determinations. With a commercial six-jet sputtering source, the Atomsource (Analyte Corp., Grants Pass, Oregon), that directly atomizes solid samples for conventional atomic absorption spectrophotometers, the sample loss rate for...
Investigations of plasma production by a pulsed dye laser
microprobe were made. Comparisons between a Q- switched and a
pulsed dye laser system were made on the intensity of the continuum
produced by atmospheric breakdown. The dye laser system was
foundtominimize the production of the continuum which in turn
allowed...
A photon-counting technique which provides direct digital read-out
of data has been developed and evaluated for the reaction rate determination
of glucose. The enzyme catalyzed oxidation of glucose
to gluconic acid and hydrogen peroxide with the subsequent reaction of
hydrogen peroxide with excess iodide to produce tri-iodide is followed
by...
The change in the oscillation frequency in the current of
an atmospheric helium glow discharge is a sensitive detector
for gas chromatography. The response of the detector is in
the femtomole and picomole range for nonane and decane. The
effluent of a capillary column is directed into a glow
discharge...
A focused Q-switched neodymium-doped glass laser with power
levels ranging from 1-6 MW and with a 50-nsec halfwidth, was used
to vaporize copper metal. Experimental measurements showed that
the amount of material vaporized away from the target was not linear
with laser power and was much less than could be...
A new three-phase argon plasma arc was developed for analytical emission spectroscopy. The power supplied to the plasma arc utilized a simple circuit with three-phase as line voltage stepped down via a transformer to 104Vrms. A three concentric quartz tubing assembly was determined to be the optimum configuration for supplying...