A novel yet simple spectrochemical technique for analyzing liquid samples has been demonstrated, which is based on pulsed laser vaporization at sub-breakdown fluences, together with acoustic normalization for improved precision. By the use of ArF laser vaporization of NaCl solution as a test case, a dynamic range of three orders of magnitude was realized, and as little as 0.23 ppm of Na can be detected. Because of the high precision and small focal volume, the absolute detectability can be as low as 0.4 pg (20 fmol). ArF laser vaporization of KCl and BaCl2 was also investigated, and detection limits of 1.5 ppm and 130 ppm were established for K and Ba, respectively.
Nai-Ho Cheung and Edward S. Yeung, "Single-Shot Elemental Analysis of Liquids Based on Laser Vaporization at Fluences Below Breakdown," Appl. Spectrosc. 47, 882-886 (1993)