Utilizing Low Sample Uptake Rates and A Nitrogen Mixed-gas Plasma for the Elimination of Oxide-based Interferences in ICPMS Analyses

Spectroscopic interferences have long negatively impacted the accuracy of inductively coupled plasma mass spectrometry (ICPMS) analyses.Of these, oxide-based interferences, the combination of an analyte with oxygen producing a new ion 16 mass units greater than the original analyte, often proves most prevalent and difficult.A cheap and reliable method that permits the mitigation of oxide-based interference would be highly beneficial.Here-in, low sample uptake rate was used to reduce the formation of lanthanide oxide-based interferences in ICPMS analyses through temperature and Le Chtelier effects.Introduction of oxide forming solutions (50 g L -1 ) composed of lanthanide elements at 1 mL/min yielded an average oxide ratio of 4.5 7.2% while introduction at 50 L L min -1 yielded 0.54 0.26%.A similar method using 2% nitrogen gas in the bulk plasma concurrently decreased oxide-based interferences.The benefits observed with low sample uptake rate and a mixed-gas plasma were combined to virtually eliminate oxide based-interferences for many of the lanthanide elements and provide a modest signal enhancement compared to an Ar plasma operated at a higher sample uptake rate.For example, when comparing the best oxide reduction method to the worst, oxide formation is mitigated by 97%.Of the three sample uptake rates tested, 235 L min -1 under mixed-gas plasma conditions offers the best balance between the oxide interferences mitigation and signal intensity.Ultimately, low sample uptake rate may prove essential in increasing ICPMS analysis accuracy while safeguarding resources and minimizing chemical waste for generations to come.