Determination of tungsten by calcium atomization inhibition titration

A method for the determination of tungsten utilizing inhibition effect on calcium emission in hydrogen-air flame is described. The technique is based on atomization inhibition titration (AIT) and subsequent release by means of lanthanum. The signal enhancement following the lanthanum addition is proportional to the tungsten concentration up to 0.8 ppm W. A detection limit of 0.013 ppm and a determination limit of 0.12 ppm were found. The effect of 13 foreign ions on the tungsten determination was investigated.