FEASIBILITY OF IMPROVEMENT IN ANALYTICAL PERFORMANCE IN LASER-ABLATION INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY (LA-ICP-MS) BY ADDITION OF NITROGEN TO THE ARGON PLASMA

Addition of nitrogen to an argon ICP in LA-ICP-MS has been found to increase sensitivity and consequently reduce oxide to metal ratios (MO+/M+) for the reference elements Ce and Th. Addition of about 1% v/v N2 to the coolant flow increased sensitivity, reducing MO+/M+ ratios from about 0.6% to about 0.2%. Addition of about 12% N2 to the cell flow had a similar effect, being greatest at a higher forward rf plasma power (1700 W). The increased sensitivity may be useful in practical analyses; N2 consumption is very small.