Cyclic flow- injection chemiluminesent analysis of a small amount of chemical contamination using an on-line solid phase extraction for concentration

本文研究了循环流动注射法测定Fe（Ⅲ）的重复性。在过氧化氢存在下，用1，10-邻菲咯啉荧光法测定Fe（III）。用常规方法测定Fe（Ⅲ）的最佳pH值为9.8。在pH 9.8时，连续测定Fe（III）时，背景信号的基线值随pH值的增加而增加，因此循环荧光法测定Fe（III）的最佳pH值为7。结果表明，循环荧光法测定Fe（III）的灵敏度较常规法明显降低。为此，采用Teflon毛细管在线固相萃取富集方法，通过单在线流动系统建立了循环流动注射分析方法，该方法包括另一条用于富集样品溶液中Fe（III）的富集线，富集时间为5 min，富集后的样品溶液中Fe（III）在毛细管内被富集 关于我们 在此基础上，在载体线上用少量乙醇在线洗脱Fe（III）。以Fe（II）、1，10-邻菲咯啉、过氧化氢、阳离子表面活性剂Zephiramine和pH缓冲剂tris为载体，建立了一种新的废水处理方法。Fe（III）在螺旋荧光池中与载体溶液反应，温度控制。以乙醇为缓冲液，100次重复测定Fe（Ⅲ），背景信号稳定，在最佳条件下，Fe（Ⅲ）的测定下限为0.1ppb。浓缩pH 8，浓缩时间5 min，浓缩毛细管长度5 m，洗脱液体积100μl，进样流速2.8ml/min，Zephiramin0.075M，双氧水20%。在0.3 ~ 100 ppb范围内，Fe（Ⅲ）浓度与荧光强度呈线性关系。测定自来水中痕量铁的结果表明，与ICP-AES的值吻合得很好。少

A circulatory flow-injection method (cyclic FIA) for the repetitive determination of Fe(III) has been studied. The Fe(III) was determined by chemiluminescent measurement using 1,10-phenanthroline in the presence of hydrogen peroxide. The best pH for chemiluminescent reaction on the analysis of Fe(III) was proposed to be 9.8 by conventional method. However, the pH for cyclic chemiluminescent determination of Fe(III) was varied to 7 as a best pH, because that the base line as a background signal increased with a continuous determination at pH 9.8.As a result, the sensitivity of Fe(III) determination by the chemiluminescent method decreased remarkably compared to that of the conventional method. Therefor, the concentration method was investigated by on-line solid extraction using a Teflon capillary tube.The cyclic FIA developed by single on-line flow system involves another line for concentration of Fe(III) in sample solution for 5 min. After the concentration of Fe(III) inner the capilla … More ry cove, the Fe(III) was eluted on-line with a small amount of ethanol in the carrier line. The carrier solution as a reagent-waste in a reservoir was composed of Fe(II),1,10-phenanthroline, hydrogen peroxide, Zephiramine (caionic surfactant) and tris (pH buffer agent). The Fe(III) reacted to the carrier solution in the chemiluminescent spiral cell under the control of temperature. The background signal by 100 times repetition-determination for Fe(III) was stable using ethanol as a elute solution.The limit of the determination for Fe(III) was 0.1ppb under the optimum conditions, i.e., pH8 for concentration, 5 min as a concentration time, 5m as a concentration capillary tube length, 100μl for the volume as a elute solution, sample flow rate 2.8ml/min, 0.075M Zephiramin, and 20% hydrogen peroxide. A linear relationship between the concentration of Fe(III) and the observed chemiluminescent intensity was obtained over the range of 0.3〜100ppb. The results of a trace iron determination in tap water showed a good agreement with the values obtained by ICP-AES. Less