Determination of long-lived radionuclides in concrete matrix by laser ablation inductively coupled plasma mass spectrometry

A laser ablation system using a Nd:YAG laser was coupled both to a quadrupole inductively coupled plasma (ICP) mass spectrometer and to a double-focusing sector field ICP mass spectrometer. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was applied for the determination of long-lived radionuclides in a concrete matrix. The investigated samples were two laboratory standards with a concrete matrix, which we doped with different long-lived radionuclides (e.g. (99)Tc, (232)Th, (233)U, (237)Np) from the ng g(-1) to mu g g(-1) concentration range and an undoped concrete material (blank). Detection limits for long-lived radionuclides in the 10 ng g(-1) range are reached for LA-ICP-MS using the quadrupole mass spectrometer. With double-focusing sector field ICP-MS, the limits of detection are in general one order of magnitude lower and reach the sub ng g(-1) range for (233)U and (237)Np. A comparison of mass spectrometric results with those of neutron activation analysis on undoped concrete sample indicates that a semiquantitative determination of the concentrations of the minor and trace elements in the concrete matrix is possible with LA-ICP-MS without using a standard reference material. (C) 1997 Elsevier Science B.V.