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LITERATURE CITED (1) Martire, D. E.; Boehm, R. E. J . Phys. Ct”. 1983,197, 1045. (2) DIII, K. A. J . Phys. Chem. 1987,97, 1980. (3) SenbeH, K. B.; Dorsey. J. G. Anal. Chem. 1989,67, 930. (4) Johnson, 8. P.; Khaledi, M. G.; Dorsey, J. G. Anal. Chem. 1988, 58,
2354.
(5) Marqlrsee, J. A.: DIII. K. A. J . the" Phys. 1988,85,434. (6) Dorrey. J. G.: MI1, K. A. Chem. Rev. 1989,89, 331. (7) HR, T. L. I n t ”
to StaLllcal Thermodynamics; Addtson-Wesley: Reading, MA, 1960. (8) Fkry, P. J. M W l c ? s of Polymer Chemistry;Comeii Ilniversity: Ithaca, NY. 1953. (9) wdebrend. J. H.; Scott.R. L. The Solubility of hbnekctrolytes; ReinW . . . Nsw . . ..
Ynrk. 1950.
(IO) Lochmuler, C. H.; HamzavI-Abedi, M. A.; Ou, C.-X. J . Ckomtogr. 1987. 387. 105. (11) auph; R. K.; Oengoda, M. E. J . chromatog. Sei. 1983, 27, 352. (12) Petrovic, S. M.; Lomlc. S.: Sefer. I. J . clrometcgr. 1985, 348, 49. (13) Schoemnekers, P. J.; BUllet, H. A. H.; Tijssen, R.; de Galan, L. J . chrrwnew. 1978, 149, 519. (14) S C h U ” k e r s , P. J.; Billlet, H. A. H.; de Galan, L. Cbromatographia 1982, 15, 205. (15) Tljssm, R.; Billlet, H. A. H.; Schoenmakers, P. J. J. Chromatogr. 1978, 722, 185. (16) -en, P. J.; B i h t , H. A. H.; de Galan, L. J . Chromtwr. 1983, 282, 107. (17) Karger, B. L.; Snyder,L. R.; Eon, C. Anal. Ct”. 1978. 50,2126. (18) Martlre, D. E.; Jaroniec, M. J . Uq. chromatog. 1985,8, 1363. (1% Homtth C.;Mdander, W.; Mdnar. I. J . chrcwnaw. 1978. 125, 129. Perfomranee LiquM chromafog(20) Melander, W. R.; Horvath, C. I n
raphy:
Advances and P 6 t q ” s ;
Howath, C.. Ed.; Academic
Press: New York, 1980; Vd. 2. (21) Sinanoglu, 0. I n Advances In Chemhl phvslcs; Hirschfeider, J. 0.. Ed.; Wiiey: New Ywk. 1967;Vd. 12,p 283. (22)Sinanogtu. 0.In Mdcrculer As.w&fkms h Bldogy; Pullman, B., Ed.; Academic Press: New York, 1968 p 427. (23) Kaliszan, R. J . Chromato@+.Sci. 1984, 22, 362. (24) Hammers, W. E.; Meurs, 0.J.: DeLigny, C. L. J . chromafogr. 1982, 246, 169. (25) El Tayar, N.; Van de Watedmurd, H.; Testa. B. J . chrometo@+.1988, 320, 293. (26) Borowko. M.;Jaroniec, M.; Piotrowska, J. J . Liq. chromatogr. 1987, 70,2033. (27) Nahum, A.; Horvath, C. J . clwcxnatog. 1981, 203, 53. (28) Bii. K. E.; Horvath, C.; Melander. W. R.; Nahum, A. J . chromatow. 1681. 203,65. (29) Reymond, D.; Chung, G. N.; Mayer, J. M.; Testa, B. J . chromato@+. isa7 .- -., 391 - - . , 97 - .. (30) Pekic. B.; Petrovic, S. M.: Siavka, 6. J . C h ” t 0 g . 1989, 268, 237. (31) Fmsaki, N.; Hada, S.; Neya, S. J . #”top. 1986, 387, 33. 1987, 384,279. (32) Arai, Y.; Huukawa, M.; Hanai, T. J . C/?fmm. (33) Kaiiszan, R. CRC Grit. Rev. Anal. Chem. 1986, 76, 323. (34) Mockel, H. J.; Welter, G.; Melzer, H. J . CJvOmelog. 1987, 388,255. (35) McCormick, R. M.; Karger, B. L. Ana/. chem.1980. 52, 2249. (36) Michels, J. J.; Dorsey, J. G., unpuWshed work. (37) Michels, J. J.; Dorsey, J. 0.J . clrometcg. 1988,457,85-98. (38) Woodburn. K. B. Doctoral Thesis, Unhrerslty of Fiorida, 1985. (39) Jandera, P. chrometo&mphh1985, 79. 101. (40) Hanai, T.; Hubert, J. W C CC, J . Hlgh ResoM. chrcwnatog. Ctwomefog. Commun. 1983,6 , 20. (41) Johnson, B. P. Doctoral Thesis, University of Fkrida, 1986. (42) Lipford, L. C.M.S. Thesis, Unhrerdty of Fkrida, 1985. (43) Smith, R. M. J . chrome-. 1987,209, 1. (44) Jinno, K.; Kawasaki, K. ChromatOgepMe 1983, 77, 337.
RECEIVED for review March 20, 1989. Revised manuscript received August 29, 1989. Accepted August 29, 1989. The authors are grateful for support of this work by NIH GM33382. K.A.D. is also grateful to the PEW Scholars Foundation for support.
Laser-Enhanced Ionization as a Diagnostic Tool in Laser-Generated Plumes Ho-ming Pang and Edward S. Yeung* Ames Laboratory-USDOE and Department of Chemistry, Iowa State University, Ames, Iowa 50011
Laew~bnkatbncanbeusedtogenerateknshthe
laser microprobe when the vaporhatbn wavelength Is tuned in- r with the analyte absorption band. A 70-fold enhancement of the ion intensity has been observed. Abnormal spectral band broadening and abarorptlon peak shMl are found. I n order to correct for pldse-to-pulse variaUons in the formath of the laser plasma, the acoustic wave generated from the Laser pkme in He was wed as the internal standard to monltor the total amount of material vaporized during each puke. Unear correlation between the acowrtlc wave and the k n signal at dlfferent laser energies and focuslng condltkns has been obtained.
INTRODUCTION The laser microprobe technique is an important solid Sample introduction method in atomic spectroscopy (1-3) and mass spectrometry (4-6).With the use of different power and wavelength conditions, neutral particles (such as atoms, clusters, and molecules) and ions can be generated in the laser plasma. However, laser microprobe analysis still remains a 0003-2700/89/0361-2546$01.50/0
qualitative or semiquantitative method (3,7)due to the uncertainties arising from the laser power fluctuations, matrix effects, surface conditions, and focusing conditions. Since the amount of material produced by the laser vaporization process depends on the pulse-to-pulse laser power stability (most modern pulsed lasers provide
