荔枝红色素分光光度法同时测定痕量价态锡

SIMULTANEOUS DETERMINATION OF Sn(Ⅱ) AND Sn(Ⅳ) BY SPECTROPHOTOMETRY OF LITCHI CHINENSES RED.

本文基于常温盐酸介质中 Sn( )、Sn( )与荔枝红色素 ( R)均能瞬时形成于λmax=550 nm的玫瑰红色化合物 ,其吸光度有加合性以及游离 Sn( )和 Sn( )离子存在于 p H不同的特性 ,首次建立不同 p H下相同波长差减法测定痕量价态锡的新方法 ,其 ε=1.7～ 2 .0 (× 10 5) L· mol-1· cm-1,用于检测合成样及鱼制品中 Sn( )与 Sn( ) ,结果满意。

A new spectrophotometric method for simultaneous determination of trace amounts of Sn(Ⅱ) and Sn(Ⅳ) is proposed.The method is based on the properties of the both Sn(Ⅱ) and Sn(Ⅳ) can formed rapidly λ max =550 nm rose red complexes with litchi chinensis red(R) in dilute HCl medium at room temperature and free Sn(Ⅱ) and Sn(Ⅳ) ions are only exist in defferential pH solutions.The amount of Sn(Ⅱ)+Sn(Ⅳ) is determined firstly in the pH 0.7 solution,then the amount of Sn(Ⅱ) is determined under pH 1.6 condition,and amount Sn(Ⅳ) can be calculated by subtraction of Sn(Ⅱ) from Sn(Ⅱ)+Sn(Ⅳ).The method is very simple and sensitive (ε 550 =1.7～2.0×10 5 L·mol -1 ·cm -1 ).It has been applide to the determination of Sn(Ⅱ) and Sn(Ⅳ) in synthesis samples and fish products with satisfactory results.