Determination of thallium in brain tissue by stable isotope dilution and field desorption mass spectrometry

The utility of field desorption mass spectrometry for quantitative metal cation analysis in forensic sciences is demonstrated by the determination of a lethal thallium level in the brain tissue of an experimental animal. Stable isotope dilution and accumulation of the electrically recorded field desorption ion currents with a multi-channel analyzer allowed a direct estimation of thallium in homogenized tissue samples without further pretreatment. Experiments with standard solutions revealed the limit of detection for thallium to be about 10 pg of the metal cation.