A critical study of the cold vapor atomic absorption and fluorescence instrumentation for the analysis of mercury is described. Some of the important modifications involve the reduction vessel, absorption cell, fluorescence cell, and radiation source. The new modified systems have much greater calibration sensitivities and lower detection limits than those...
Plasma sources with multiple electrodes have been developed and
characterized in this research for atomic emission spectroscopy.
Multi-electrode plasma sources use electrodes to shape the plasma in
order to continuously entrain a sample stream in the center of hot
plasma, in a manner similar to an inductively coupled plasma (ICP)...
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...
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...
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...
Three aspects of glow discharges have been studied: glow discharge oscillations,
sputtering, and coupling between cathode and anode regions the two most important
regions in a glow discharge. Cathode and anode processes are tightly coupled by electron
and ion coupling effects. Both electron and ion coupling effects were observed by...
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...
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...
The variable length, six-electrode plasma source for atomic
emission spectroscopy described here is operated from three
compact, simple, and inexpensive direct current power supplies. The
vertical arcs formed between the three electrode pairs completely
entrain the sample and are typically operated at 40 V and 20 A.
Three concentric quartz...
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...
Spectrometric detection systems for gas chromatography
(GC) based on gas phase ultraviolet absorbance
and fluorescence measurements have been developed and
evaluated in this research. Polynuclear aromatic compounds
(PNAs) are selectively detected by these systems.
Limits of detection for PNAs range from 4 ng to 90 ng
for absorbance determinations, and...
A long path dc plasma arc operated in an atmosphere of
argon is described. The arc is easily ignited and operated, and
is inexpensive to use. Samples were introduced into the arc as
solution aerosols. Radially resolved emission measurements are
reported for calcium, copper, and hafnium. The detection limit
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...
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 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...