Indirect extraction—spectrophotometric method for the determination of traces of tin(II) by means of 4,7-diphenyl-1,10-phenanthroline

An indirect extraction-spectrophotometric determination of tin(II) is based on reduction of iron(III) and determination of the iron(II) formed with bathophenanthroline. Analysis is possible in strongly acidic samples even with large excesses of iron(III). The apparent molar absorptivity is 39,080 dm³ mol^-1 cm^-1 ; the limit of determination is 32 ng cm^-3 and the sensitivity is 64 ng cm^-3. Interferences are reported. The method is applicable to the determination of tin in samples soluble in non-oxidizing acids, and to the determination of tin in lead.