オンライン膜濃縮/酸溶出による水中の微量亜硝酸イオンの吸光光度定量

概要

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An on-line preconcentration method incorporated with a membrane filter for the deter-mination of trace nitrite in water was studied. Nitrite was reacted with 4-aminobenzene-sulfonic acid to be converted into 4-sulfobenzenediazonium ion, then coupled with N-(l-naphtyl)ethylenediamine to form an azo dye. A solution of benzyldimethyltetradecyl-ammonium was added to the solution at pH 10 where the azo dye is an anion. One ml of the solution was loaded from an injector to the line, and the azo dye was collected on a cellulose nitrate membrane devise attached to the line as an ion-associate with a cationic surfactant. The azo dye on the filter was eluted with an acidic medium of pH 1,which was loaded from the same injector. The absorbance at 550 nm due to the azo dye was monitored with a UV/VIS detector. The calibration graph was linear up to 100μg dm^<-3> NO_2^-; the detection limit was defined as three-times the standard deviation of the blank on 3.3 μg dm^<-3> No_2^-. This method has the following advantages : free of any organic solvent, small sample volume, high sensitivity, and low analysis cost. The recoveries of the nitrile added to river-water samples were satisfactory.
社団法人日本分析化学会の論文
1997-05-05