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本文研究了Fe(Ⅱ)与2—(5—溴—2一吡啶偶氮)—5—二乙氨基苯酚络合物的结构,稳定常数,显色条件和测定食品中微量铁的方法。结果表明在pH3.6～10的吐温—80介质中,络合物分子中Fe(Ⅱ)与2—(5—溴—2—吡啶偶氮)—5—二乙氨基苯酚的摩尔比为1:2,络合物的稳定常数为1.38×10~(10),吸光系数ε_(7(?)4)=2.79×10~4L·mol~(-1)cm~(-1),Fe(Ⅱ)在0～35μg/25ml范围内服从Beer定律。常见Cu~(2+)、Zn~(2+)、Cd~(2+)、Hg~(2+)、Mn~(2+)、Ni~(2+)等阳离子和SO_4~(2-)、NO_(?)~-、PO_4~(2-)等阴离子均无干扰。本法具有简便、快速、灵敏度、选择性和准确性高等特点。用于测定食品中微量铁结果令人满意。
In this paper, the structure, stability constants and color conditions of Fe (Ⅱ) and 2- (5-bromo-2-pyridylazo) -5-diethylaminophenol were studied. The results showed that the molar ratio of Fe (Ⅱ) to 2- (5-bromo-2-pyridylazo) -5-diethylaminophenol in the complex was 1: 2, the stability constant of the complex was 1.38 × 10 ~ (10), the extinction coefficient ε_ (7) 4 = 2.79 × 10 ~ 4L · mol ~ (-1) cm ~ (Ⅱ) Beer’s law was obeyed in the range of 0 ~ 35μg / 25ml. Common cations such as Cu 2+, Zn 2+, Cd 2+, Hg 2+, Mn 2+, Ni 2+ and SO 4 4- ), NO_ (?) ~ -, PO_4 ~ (2-) anions and other non-interference. This law is simple, fast, sensitive, selective and high accuracy. For the determination of trace iron in food results are satisfactory.