试剂7－（8＇－羟基喹啉偶氮）－8－羟基喹啉－5－磺酸荧光光度法测定镁（Ⅱ）的研究

Fluorimetric determination of magnesium (Ⅱ)by using the reagent 7-(8'- hydroxy qu noline azo)-8-hydroxy quinoline-5-sulfonic acid

新合成了试剂７－（８＇－羟基喹啉偶氮）－８－羟基喹啉＼５－磷酸（简称８ＱＡ８Ｑ５Ｓ），并对其进行结构鉴定，研究了试剂荧光光度法测定镁的反应条件。镁与试剂在ｐＨ１０．３０氨水／氯化铁缓冲介质中形成２：１的络合物并呈现荧光，其λｅｘ／λｅｍ＝２６０／４８８（ｕｍ），线性范围为０～１２μｇ／２５ｍＬ，检测限为３．１２ＰＰｂ，考察了共存离子的干扰，并直接应用于合金样中镁的测定，结果满意。

A new fluorimetric method of determination for magnesium(Ⅱ) is described. The method is based on the fluorescent complex of 8QA8Q5S with Mg(Ⅱ) at λex/λem = 2C0/488 (nm). The composition of complex is Mg:R = 2: 1 at PH 10. 30, a good linear relation ship was obtained over the range of 0～12μg/25mL Mg(Ⅱ) and the limit of detection for Mg(Ⅱ) is 3.1 ppb. The method has been directly used to determine trace Mg(Ⅱ) in samples with satisfactory results.