| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 2005: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2004: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2003: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
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
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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
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