析相萃取火焰原子吸收光谱法测定水样中痕量铁

FAAS DETERMINATION OF TRACE AMOUNTS OF IRON IN WATER AFTER ITS PRECONCENTRATION BY PHASE SEPARATION EXTRACTION

研究了析相萃取火焰原子吸收光谱法测定水样中铁的方法 ,在酸性条件下 ,Fe3 + 与SCN- 生成络合物 ,在适当的温度下 ,被TritonX 10 0 正辛醇 水体系萃取富集。析出相用火焰原子吸收进行测定。方法检出限为 0 .0 0 4 μg·ml- 1,用于水样中痕量铁的测定 。

Trace amounts of iron(Ⅲ) [less than 5μg of Fe(Ⅲ) per 25ml of solution] were preconcentrated in the form of Fe(SCN) 3- 6 from an acidic solution of 0.004mol·L -1 H 2SO 4 by the phase-separation extraction method using a mixture containing Triton X-100, n-octylalcohol and water, as phase-separation agent. The phase-separation was completed when the solution in the graduated test tube was heated for 10min in a water bath at 30℃. Then iron was determined directly by FAAS in the separated phase (i.e. the upper layer of the solution). The working conditions of the instruments were as follows wavelength for measurement 248.3nm, width of spectral band 0.2nm, lamp current 2.5mA, height of observation 4mm, flow-rate of air 5.5L·min -1, flow-rate of acetylene 1L·min -1. The detection limit attained to 0.004μg of Fe(Ⅲ) per ml of solution. Satisfactory results were obtained by this method in the analysis of water samples.