Inductively coupled plasma or microwave plasma are among the most reliable and common spectroscopic techniques used for the determination of metals, including PGMs. These instruments are versatile and allow for high-sensitivity multi-element analysis. However, in order to achieve such high sensitivity, dissolution (partial or complete) of the samples must be performed.
For matrices containing refractory materials, as is the case for most PGM substrates, alkaline fusions typically allow a more complete dissolution and a faster analytical throughput than all other common dissolution methods combined. However, the high amount of salts in the dissolved fraction is currently affecting the popularity of alkaline fusions in the plasma chemistry world. This is particularly significant for microwave plasma which operates at lower temperatures. Therefore, it is critical to reduce the amount of salts dissolved in the sample following alkaline fusions before its introduction into the analytical system.