Laser ablation for direct elemental analysis of solid samples by inductively coupled plasma mass spectrometry

The results of a preliminary study on direct analysis of solid metals and nonconductive samples by inductively coupled plasma mass spectrometry (ICP-MS) are described. The aerosols ablated from solid samples by a ruby laser are introduced into an inductively coupled plasma, with detection of the resulting ions by a mass spectrometer. With conventional solution introduction, polyatomic species from mineral acids and solvents prevent the accurate determination of some trace analyses. However, using laser ablation, these background peaks are greatly reduced. The relative sensitivity factors for the laser ablation method are seen to vary from unity, with volatile elements such as Pb and Bibeing more sensitive. Detection limits of rare-earth elements, Th and U in silicate rocks are excellent (0.02-0.9 ppm at the effective integrating time of 1.4s), being better than those of the examined elements in steel (1.7-29 ppm at the effective integrating time of 0.6 s). (author)