An Extractive Spectrophotometric Determination of Tin as Sn(II)-6- Chloro-3-hydroxy-7-methyl-2-(4'-methoxyphenyl)-4-oxo-4H-1-benzopyran Complex into Dichloromethane

Abstract

Tin(II) forms a yellow colored complex with 6-chloro-3-hydroxy-7-methyl-2-(4'-methoxyphenyl)-4-
oxo-4H-1-benzopyran in hydrochloric acid medium. The complex is extractable into dichloromethane
and shows maximum absorbance in the range 424-428 nm. The 1:2 (M: L) complex formed is found to
be stable for more than 4 h in dichloromethane. Beer’s law is obeyed in the range 0.0 to 1.68 µg Sn(II)
mL-1 with an optimum range of determination as found from Ringbom plot is 0.23-1.51 µg mL-1
. The
molar absorptivity and Sandell’s sensitivity of the complex are 6.29×104 L mol
-1 cm-1
and 0.0019 µg
Sn(II) cm-2
at 426 nm, respectively. The method is free from interference of a large number of
important anions/complexing agents and cations. The method is quite simple and has been
satisfactorily applied to the analysis of tin in various samples including gun metal and tin can.