定量テープと気液分離管を用いる水溶液中のシアン化物イオンの測定

概要

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A sample solution was pumped at a flow rate of 3 ml min^<-1> to the mixing joint, where a sulfuric acid (0.05 M) was mixed at a rate of 2 ml min^<-1>. A mixture containing hydrogen cyanide was fed into a gas-liquid separation tube (pore size, 1μm; microporous Teflon tube of 2 mm i.d., 3 mm o.d., 900 mm length). Hydrogen cyanide evolved from the gas-liquid separation tube was purged by purified air (400 ml min^<-1>) onto HCN monitoring tape. The efficiency of the gas-liquid separator used was about 3%. The monitoring tape used was porous cellulose tape containing silica gel, N,N-diethyl-p-phenylenediamine, Cu(CH_3COO)_2 and glycerin. When the tape was exposed to HCN gas, the tape became colored homogeneously. The degree of color intensity was proportional to the concentration of CN^- in the sample solution. The relative standard deviation of the response to 0.1 mgCN^- cm^<-3> was 1.2%. The calibration curve showed a rectilinear behavior in the range of 0.01〜0.3 mgCN dm^<-3>. The method has detection limits of 0.01 mgCN dm^<-3> for free cyanide ion with a sampling time of 5 min. This method could detect free cyanide ions, and indirectly Cu(II) and Cd(II) cyano complexes when the metal concentrations were below 10 mg dm^<-3>.
社団法人日本分析化学会の論文
2004-11-05