2-〔2-苯并噻唑偶氮〕-5-二乙氨基苯甲酸分光光度法测定铝合金中微量铁

Spectrophotometric Determination of Trace Amounts of Iron in Aluminium Alloy with 2- [ 2-Benzothiazolylazo ] -5-Diethylaminobenzoic Acid

合成了2-[2-苯并噻唑偶氮)-5-二乙氨基苯甲酸(BTAEB)并研究了它与铁(Ⅱ)的显色反应。结果表明,在十二烷基硫酸钠存在下铁(Ⅱ)与BTAEB形成一种稳定的蓝色配合物,其最大吸收波长为641nm,表观摩尔吸光系数ε=9.0×10~4。配合物中铁(Ⅱ)与BTAEB的组成比为1:2。铁含量在0～l0μg/25ml范围内呈良好的线性关系。反应的适宜pH范围为5.0～7.5。在氟化钠和硫脲存在下反应具有较高的选择性,应用于铝合金中微量铁的测定,结果令人满意。

2-[ 2-benzothiazolylazo ]-5-diethylatninobenzoic acid (BTAEB) had been synthesized and its colour reaction with Iron(Ⅱ) was studied. In the presence of sodium dodecyl sulfate,iron ( Ⅱ ) reacts with BTAEB to form a stable blue complex. The complex exhibits an absorbance maximum at 641nm, The apparent molar absorptivity was found to be 9.0×104. The molar ratio of Fe (Ⅱ) /BTAEB in the complex was estimated 1 : 2. The optimal pH range for the colour reaction is 5.,0-7.5. The calibration graph is linear over the concentration range of 0-10ug Fe in 25ml. In the presence of sodium fluoride and thiourea, the method is highly selective. It was applied to the determination of iron in aluminium alloys with satisfactory results.