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.