This part of EN 725 describes a method for the determination of impurities in barium titanate powders using inductively coupled plasma optical emission spectroscopy (ICP-OES).
The method is applicable only to stoichiometric barium titanate. The maximum concentrations measured for each impurity are as follows:
Sr 4 mg/g (4 000 ppm)
Ca 500 ug/g (500 ppm)
K 200 ug/g (200 ppm)
Na, Mg, Al, Fe, Nb 100 g/g (100 ppm)
The minimum concentration or detection limits are from 1 ug/g to 5 ug/g (1 ppm to 5 ppm).