Laser Microprobe of Alkali Elements in Organic Compounds

• Published in: Japanese Journal of Applied Physics 1984-01, Vol.23 (10R), p.1336
• Main Authors: Yamamoto, Takashi, Munakata, Toshiaki, Nomiya, Yoshio, Tsukakoshi, Motowo, Kasuya, Takahiro
• Format: Article
• Language: English
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.23.1336

Laser microprobe mass-spectroscopic detection was applied to inorganic elements in an organic specimen with the intention of obtaining the basic characteristics of the specimen for biomedical application. The fourth harmonic of an Nd:YAG laser was employed as the radiation source. An organic compound containing alkali elements of low concentration and high homogeneity was used as the specimen. The time-of-flight measurements and mass-spectroscopic observations were performed for ions emerging from the laser-produced microplasma. The highest kinetic energy of ions E h and the total number N T of Na ions were found to be scaled by the laser intensity φ 1 as E h ∝φ 1 0.39 and N T ∝φ 1 1.1 , in the range of 3×10 7 to 3×10 8 W·cm -2 . The kinetic energy of ions extended to several hundred eV for laser irradiation of the order of 10 8 W/cm 2 , and spread over about 100 eV as evaluated from the FWHM of the TOF profiles. A sensitivity of better than 10 -8 g was achieved with ease for a single-shot laser mass-analytic detection of Na, Ca, and Cs in the organic compound.