Preconcentration of thallium(III) with 2,6-bis(N-phenyl carbamoyl) pyridine on microcrystalline naphthalene prior to its trace determination in human serum spectrophotometrically

A novel, simple, sensitive and effective method has been developed for preconcentration of thallium on 2,6-bis(N-phenyl carbamoyl)pyridine-naphthalene adsorbent in the pH range 5.0–10.0, prior to its spectrophotometric determination, based on the oxidation of bromopyrogallol red at λ = 518 nm. This method makes it possible to quantitize thallium in the range of 3.0 × 10−9 to 1.0 × 10−5 M, with a detection limit (S/N = 3) of 1.2 × 10−9 M. This procedure has been successfully applied to determine the ultra trace levels of thallium in the environmental and biological samples, free from the interference of some diverse ions. The precision, expressed as relative standard deviation of three measurements is better than 4.17%.