Trace analysis of impurities in sol-gel prepared BaTiO3-powders with ICP-MS

An ICP-MS method for the determination of ultra-trace impurities of 21 elements (Be, Al, Ca, Cr, Mn, Co, Ni, Sr, Zr, Ag Cd, In, Sn, La, Ce, Er, Hf, W, Pb, Bi, U) at pg/g to ng/g level in BaTiO₃-powders and precursors prepared by different sol-gel-methods was developed. The non-spectral matrix effects like suppression of the analyte signal and spectral effects like the formation of polyatomic ions like MO⁺, MAr⁺, MCl⁺ and M²⁺ which interfere with isotopes in isobar overlaps was investigated. To correct for these polyatomic ions a “blank solution” with the composition of the sample matrix was measured and the data were subtracted from the results of the sample; a standard addition method for calibration and ⁴⁵Sc, ⁸⁹Y, ¹⁰³Rh and ¹⁴¹Pr as internal standards to compensate the matrix effects were used and improvements in accuracy and precision were shown. The stability of the instrument and the detection limits in the presence of the barium and titanium matrix were established. In BaTiO₃ different amounts of trace impurities were detected in the μg/g to ng/g range. The main impurities are strontium and calcium. The source of the impurities are mainly the educts but it is shown that contamination during the synthesis process is also possible.