Exploration of microwave plasma source cavity ring-down spectroscopy for elemental measurements.
We are exploring sensitive techniques for elemental measurements using cavity ring-down spectroscopy (CRDS) combined with a compact microwave plasma source as an atomic absorption cell. The research work marries the high sensitivity of CRDS with a low-power microwave plasma source to develop a new instrument that yields high sensitivity and capability for elemental measurements. CRDS can provide orders of magnitude improvement in sensitivity over conventional absorption techniques. Additional benefit is gained from a compact microwave plasma source that possesses the advantages of low power and low-plasma gas flow rate, which are of benefit for atomic absorption measurements. A laboratory CRDS system consisting of a tunable dye laser is used in this work for developing a scientific base and demonstrating the feasibility of the technique. A laboratory-designed and -built sampling system for solution sample introduction is used for testing. The ring-down signals are monitored using a photomultiplier tube and recorded using a digital oscilloscope interfaced to a computer. Lead is chosen as a typical element for the system optimization and characterization. The effects of baseline noise from the plasma source are reported. A detection limit of 0.8 ppb (10(-)(10)) is obtained with such a device.
C-ACS, MS K484, Los Alamos National Laboratory, New Mexico 87545, USA. yduan@lanl.gov
Yixiang
Y
Duan
Chuji
C
Wang
Christopher B
CB
Winstead
D000465:Algorithms; D004602:Elements; D007202:Indicators and Reagents; D007854:Lead / Q000737:chemistry; D008872:Microwaves; D015203:Reproducibility of Results; D013054:Spectrophotometry, Atomic / Q000295:instrumentation*
D004602:Elements; D007202:Indicators and Reagents; D007854:Lead