【摘要】 本文研究了1-（5-溴-2-吡啶偶氮）-2-萘酚-6-磺酸（5-Br-PAN-S）与铁（Ⅱ）的显色反应,试验表明,在pH3～10范围内铁（Ⅱ）与5-Br-PAN-S形成稳定的络合物,络合物在550nm和750nm有二个吸收峰,其表现摩尔吸光系数分别为2.31×10⁴和1.77×10⁴L·mol^-1·cm^-1。络合物组成比为铁（Ⅱ）:5-Br-PAN-S=1:2,络合物稳定常数为1.82×10²⁴,铁量在0～60μg/25ml（750nm）范围内服从比尔定律。用本法直接测定了人发和食品中微量铁,结果满意。更多还原

【Abstract】 Color reaction of iron(Ⅰ) with l-(5-bromo-2-pyridylazo)-2-naphthol-6-sulphonic acid (5-Br-PAN-S) has been studied. Iron(Ⅰ) reacts with 5-Br-PAN-S at pH 3-10 to form a stable 1 : 2 chelate in aqueous solution. The apparent molar absorptivity of this chelate is 2. 31 ×104(550 nm) and 1. 77×104(750 nm) L ?mol-1 ?cm-1. Beer’s law is obeyed in the range of 0-60 μg/25 ml for iron (750 nm). The proposed method has been applied to the determination of trace iron in human hair and food with satisfactory results.更多还原