Laser ablation-inductively coupled plasma-mass spectrometry: Examinations of the origins of polyatomic ions and advances in the sampling of particulates

Ongoing issues that affect the continued maturation of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) are studied. Spectral interferences in the form of polyatomic ions can hinder the analytical abilities of this method. Differences in the origins of polyatomic ions in solution nebulization ICP-MS versus LA-ICP-MS are investigated through observation of metal oxide (MO+) ions. Conditions responsible for the measured MO+ abundances are described via the measured gas kinetic temperature (Tgas). The effect of additional gases (nitrogen and helium) on the ICP and MO+ ion abundances is also studied using this method. Tgas measurements are also used to establish the origin of metal argide (MAr+) ions during LA-ICP-MS experiments and describe conditions during the ion extraction process. The fitness of femtosecond (fs)-LA-ICP-multicollector (MC)-MS for the determination of U isotope ratios from particulates is examined. Advantages of this method over sample dissolution techniques for environmental monitoring are discussed.