| Abstract: | ABSTRACT A highly sensitive azo dye, 2-(5-nitro-2-pyridylazo)-5-[N-n-propyl-N-(3-sulfopropyl)amino]phenol (Nitro-PAPS), is used as a colorimetric reagent for the determination of tin(IV) content. Nitro-PAPS reacts with tin(IV) to form a water-soluble complex in 1.0 M acetic acid. Full color development is attained within 5 minutes, and maintains constant absorbance for at least 24 hours. The apparent molar absorptivity is 7.7 x 104 dm3 mol?1 cm?1 at a maximum wavelength of 580 ran. Beer's law is obeyed for tin(IV) in the range of 0-1.2 μg ml?1. The proposed method is successfully applied to the determination of trace amounts of tin in steels. |
