4-(2-噻唑偶氮)连苯三酚与钼(Ⅵ)显色反应的研究及应用

Study on chromogenic reaction of molybdenum(Ⅵ) with 4-(2-thiazolylazo)-1,2,3-trihydroxybenzene and its application

在溴化十六烷基吡啶存在下，研究了新试剂4-（2-噻唑偶氮）连苯三酚（TATB）与钼（Ⅵ）的显色反应性能。在PH1．6～4．2的氯乙酸-氯乙酸钠缓冲介质中，4-（2-噻唑偶氮）连苯三酚与钼㈣形成2：1的红色络合物，该络合物的最大吸收波长λmax在550nm处。25mL溶液中，钼质量在0～50μg范围内服从比尔定律，测定的表观摩尔吸光系数为5．48×10^4L·mol^-1·cm^-1加入氟化钠、抗坏血酸及苦杏仁酸溶液可分别消除Al3＋，Fe3＋和Ti（Ⅳ）的干扰。所拟方法用于合金样品中微量钼的测定，相对标准偏差为2．18％～2．75％，结果与认定值及5-Br-PADAP法测定结果相吻合。

The chromogenic reaction of molybdenum（Ⅵ） with the reagent 4-（2-thiazolylazo）-1,2, 3-tri- hydroxybenzene in the presence of cetylpyridimium bromide has been studied in detail. Molybdenum（Ⅵ） reacts with the reagent to form a stable red complex （1 ： 2） in the medium of pH 1.6-4. 2, The maximum absorption of the complex lies at 550 nm with the apparent molar absorptivity of 5.48×10^4L·mol^-1·cm^-1. Beer＇s law is obeyed in the range of 0--50μg for molybdenum（Ⅵ） in 25 mL solution. Using NaF, ascorbic acid and mandelic acid as masking reagents to avoid interferences from Al3＋ ,Fe3＋ and Ti（Ⅳ） respectively, the proposed method has been applied to the determination of molybdenum in alloy steel standard samples with relative standard deviation （RSD） of 2.18%--2.75% and the determination results are consisted with the certified values or those obtained by 5-Br-PADAP spectrometry.