ポリテトラフルオロエチレンチューブ予備濃縮法を利用するN,N'-ビス(サリチリデン)-2,3-ジアミノベンゾフランによる蒸留水中マグネシウムの蛍光分析

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The flow injection fluorometry of an ultra-trace amount of magnesium ion was investigated by an on-line concentration method using a PTFE tube. In a weak alkaline solution, magnesium ions were adsorbed and concentrated on the inner surface of a PTFE tube which had been treated with a 2 M NaOH solution for 3 hours at 70℃. Then, magnesium adsorbed on PTFE was eluted with 0.1 M HCl quantitatively, and then mixed with a N,N'-bis-salicylidene-2,3-diaminoben-zofuran(SABF) dioxane solution and dimethylamine buffer. Magnesium ions reacted with SABF and formed a Mg-SABF complex in the flow tube, and was determined by on-line fluorometry. Although the presence of calcium ions interfered with the concentration of magnesium, it was removed by the addition of o,o'-bis(2-aminoethyl)ethyleneglycol-N,N,N',N'-tetraacetic acid(GEDTA) as a masking agent. The optimum conditions were as follows : inner diameter of PTFE tube, 0.5 mm; length of PTFE tube, 3 m; concentration pH, 10.3; sample flow rate, 2 ml/min; complexing pH, 10.4; concentration time, 3 min; carrier, 50% dioxane; measurement wavelength : E_x=475 nm, E_m=545 nm. The detection limit was 82 ppt. The result for the determination of magnesium was 3.1 ppb in distilled water, which shows good agreement with the value obtained by ICP-AES.
社団法人日本分析化学会の論文
2003-01-05