【摘要】 研究了显色剂 2 -(5 -溴 -2 -吡啶偶氮 ) -5 -二乙氨基苯酚 (简称 5 -Br-PADAP)与铁 (Ⅱ )显色反应的条件 ,在pH =5 .0的醋酸钠 -醋酸缓冲体系中 ,采用非离子表面活性剂OP增溶增敏。铁 (Ⅱ )与显色剂形成的配合物的组成为M∶R =1∶2 ,其lgβ2 =17.74,最大特征吸收峰位于 743.2nm ,表观摩尔吸光系数ε =2 .82× 10 4L·mol- 1 ·cm- 1 。铁 (Ⅱ )含量在 0～ 30ug/2 5mL范围内能很好地服从比耳定律。该法操作简单 ,准确且选择性良好。可用于水样中微量价态铁的测定 ,结果令人满意更多还原

【Abstract】 The conditions of the color reaction of 2-(5-Bromo-2-pyridylazo)-5-Diethyl-aminophenol(Abbreviate 5-Br-PADAP) with bivalent Ferrum are studied in this paper.In the presence of NaAc-HAC suffer solution(pH is approximately 5.0),A stable red\|videt complex with the composition M∶K=1∶2 is formed from the reaction of Fe(II) with the chromogenic reagent.The maximum absorption peak is at 743.2 nm and apparent molar absorption coefficient is 2.82×10\+4 L·\{mol\}\+\{-1\}cm\+\{-1\}.Beer’s law is obeyed in the range of 0～30 μg/Fe(Ⅱ)per 25 mL. The operation is very simple,sensitive,accurate and its selectivity is very good.The method is applied to determine trace bivalent & trivalent ferrum in water with satisfactory results.更多还原