The supernatant was analyzed for Al, Ba, Mn, Ti, and V by Inductively Coupled Plasma Optical Emission Spectroscopy (ICP‒OES, Spectra Arcos SOP, German) which is a method for atomic emission spectroscopy analysis using a light source that generates plasma discharge through high-frequency inductive coupling and by ICP‒MS for Ce, Sc, and Y.
The supernatant was extracted and analyzed by High Resolution Inductively Coupled Plasma Mass Spectrometry (HR‒ICP‒MS) to determine Mn, Al, Ba, Ti, Ce, V, Sc, and Y.