Laser-Enhanced Ionization Spectrometry: Characterization of Electrical Interferences

Abstract

The electrical interferences associated with laser-enhanced ionization (LEI) spectrometry are characterized in this study. This was accomplished by comparison of LEI signal behavior in acetylene/air and hydrogen/air flames. A discussion of the relationship of the analytical signal and the total ion concentration in the flame is presented. The results of flame composition experiments are discussed as well as the role of matrix ions in determining signal strength. Experiments with modified sensing electrodes and higher applied voltages illustrate a partial remedy for electrical interferences.

Acid effects in laser-enhanced ionization spectrometry

“…The experimental apparatus has been described previously (11). The excitation source, a CMX-4 linear flashlamp pumped dye laser with frequency doubling capability (Chromatix, Inc., Sunnyvale, CAI, was operated at 10 Hz with rhodamine 6G laser dye (Exciton Chemical Co., Dayton, OH).…”

“…Previously electrical interferences due to low ionization potential matrices have been examined for rod (11) and plate (12) electrodes. The present work is concerned with the effects of mineral acids on LEI signals.…”

Lasers in Atomic Collisions, Cold Plasma and Cold Atom Physics

“…However, systematic, extensive and practical applications of this interesting effect were only possible when tuneable dye lasers were available in the decade of 1960. In 1970 the technique was mature enough to allow studies of electron excitation from metastable states with high resolution (Green et al (1980)) and the spectroscopic studies of refractory elements in hollow cathode discharges. Incidentally, the study of refractory elements had been hampered in the past due to the need of complex ovens of high temperatures.…”

Pre-Amplifier for Laser Enhanced Ionization Spectrometry

“…The values have been experimentally determined for the pulsed dye laser used in this laboratory (9). A cutoff frequency of 20 kHz can be read from the Bode plot for the given circuit values (Figure 4).…”

“…Therefore it is necessary to recover a small signal from a large background. To date, flashlamp-pumped dye lasers have proven to be the most successful excitation source for LEI spectrometry (2)(3)(4)8,9). Ambient noise arises from radiofrequency interference (RFI) which invariably accompanies pulsed laser operation.…”