The analysis of geological materials poses a challenge due to their matrix composition and the sample preparation process required to convert the samples into solution. A commonly used sample preparation technique for geological samples is lithium fusion, which involves mixing the sample with excess lithium borate and heating until the lithium borate melts and dissolves the sample to form a homogenous mass. The resulting solid is dissolved in acid for analysis.
Fusion samples are some of the most punishing samples for an ICP-OES sample introduction system, as they contain high concentrations of Group I elements (such as lithium, sodium, and potassium), which can result in deposits on the nebulizer and injector, resulting in signal drift. In addition, the high concentrations of Group I elements may cause rapid devitrification of the quartz torch, so obtaining accurate results with good precision over longer time intervals is challenging. However, with the proper choice of sample introduction components, these challenges can be overcome.
This work describes the analysis of fusion samples leveraging the PerkinElmer Avio® 550 Max fully simultaneous ICP-OES, with a focus on long-term stability.