微量镁的Mg^(2+)—BPR—CTMAB分光光度法测定

Spectrophotometric Determination of Magnesium with Mg^(2+)-BPR-CTMAB Colour Reaction

本文研究了Mg^(2+)—溴邻苯三酚红(BPR)—溴化十六烷基三甲基氯化铵(CTMAB)的显色反应,探讨了Mg2+—BPR—CTMAB体系的最佳测定条件。实验表明Mg^(2+)—BPR—CTMAB体系的最佳pH=9—10,λ_(max)=680nm,ε=1.3×10~4L·mol^(-1)·cm^(-1),镁量在0—80μg/50mL内符合比尔定律,该法用于测定铝合金中镁获得满意的结果。

The colour reaction of bromopyrogallod red (BPR) and cetyltrimethylammonium bromide (CTMAB) with Mg^(2+) has been studied in this paper. The conditions of the colour reaction with Mg^(2+)—BPR—CTMAB has been investigeted The maximun absorptions and apparent molar absorptivity were found to be 680 nm and 1.3×10~4 L/moL·cm respectively in pH=9. 50NH_3·H_2O—NH_4C1 buffer medium. The method was applied to the determination of trace Magnesium in alloy and a satisfactory result was obtained.