Flow injection flame atomic spectrometric determination of iron, calcium, magnesium, sodium and potassium in ceramic materials by using a variable-volume injector

Summary A series of different ceramic materials, such as porcelain, feldspar, kaolin, varnish, clay and stoneware have been analyzed. Iron, calcium and magnesium have been determined in these materials by flame atomic absorption and sodium and potassium by flame emission. The use of a variable-volume injector enables one to carry out these analyses in a flow system (after fusion of samples with lithium metaborate) and does not require different dilutions for the determination of each type of sample considered, nor the use of different flow injection manifolds. The developed procedure provides a limit of detection of 100 g/l for Na, 70 g/l for Ca, 50 g/l for both Fe and K and 8 g/l for Mg. The coefficient of variation obtained for the absorbance measurement is of the order of 0.5–2%. A series of 17 real samples were analyzed by the proposed procedure and the obtained results turned out to be comparable to those found by batch analysis.