正交试验法测定痕量铁的研究——微晶石蜡柱固相萃取体系

Determination of Trace Iron(Ⅱ) by Orthogonal Design

本文成功地建立了以微晶石蜡柱为固相萃取剂,以2-(5-溴-2-吡啶偶氮)-5-二乙氨基酚(5-Br- PADAP)为显色剂的固相革取光度法测定痕量铁的新方法,并采用正交试验法考查了测定条件。方法基于在 pH=4.5的缓冲溶液中,铁(Ⅱ)与5-Br-PADAP形成稳定的配合物,在λ=742nm处进行测定,其摩尔吸光 系数为:ε742=2.61×105L·mol-1cm-1,检测限为:0.218μg·L-1,铁含量在0-0.4μg·mL-1范围内服从比尔 定律。该方法用于水样中痕量铁的测定,结果满意。

The color reaction of iron(Ⅱ) with 2 - ( 5 - bromo - 2 - pyridylazo) - 5 - diethylaminophenol ( 5 - Br - PADAP) has been studied in microcrystalline paraffin phase extraction system by orthogonal design. Iron(Ⅱ) reacts with 5 - Br -PADAP at PH4.5 to form a stable complex in aqueous solution . The apparentmolarabsorptivity of the complex is 2.61×105L·mol-1·cm-1( at 742nm ) . Beer's law is obeyed in the range of 0-0.4μg·mL-1 foriron( at 742nm ) . The proposed method has been applied to the determination of trace iron in water with satisfactory results.