Determination of alkali metals by laser-induced atomic-ionization in flames.
The technique of laser-induced atomic-ionization (AI) in flames has been used for direct determination of Na, K, Rb, and Cs in samples such as water, high-purity alkali metals and their salts and polymeric organosilicon compounds. Different procedures for sample introduction into the flame were studied: (a) the sample was placed onto the cathode of the detector (this gave limits of detection for Na and Cs of 4 x 10(-16) and 2 x 10(-15) g, respectively), (b) electrothermal vaporization and (c) aspiration of the sample into the flame. To reduce the interference of SiO(2) in the AI determination of K in polymeric organosilicon compounds (at the level of 10(-3)-10(-5)%), a procedure involved additional electrical heating of the FID cathode was developed. The efficiency of certain schemes for the laser stepwise and two-photon excitation of atoms was compared for determination of Na.
Chaplygin
V I
VI
Department of Chemistry, Lomonosov State University, V-234 Moscow, 119899, USSR.
Kuzyakov
Y Y
YY
Novodvorsky
O A
OA
Zorov
N B
NB