Extraction-Spectrophotometric Determination of Tin in Environmental Samples

A highly selective and sensitive method for the spectrophotometric determination of tin(IV) in industrial waste waters is described. It is based on the selective extraction of tin(IV) with bromide into a chloroform solution of N,N′-diphenylbenzamidine(DPBA), and subsequent treatment with iodide. The molar absorptivity of the iodostannate complex formed is (1.50) × 104 l mole−1 cm−1 at λmax = 385 nm. The detection limit of the method is 0.1 ppm. The method is highly selective as none of the common metals and anions tested interfere.