- 著者
-
加藤 徳雄
- 出版者
- 公益社団法人 日本分析化学会
- 雑誌
- 分析化学 (ISSN:05251931)
- 巻号頁・発行日
- vol.50, no.9, pp.627-630, 2001-09-05 (Released:2009-02-27)
- 参考文献数
- 7
According to the present JIS method, which describes the determination of ammonia (NH3) in flue gas, the presence of more than 10 times as much sulfur dioxide (SO2) as NH3 results in interference with the determination of NH3 by indophenol blue absorptiometry. The magnitude of interference from the coexisting sulfur dioxide and its elimination of described. The magnitude of interference was investigated using NH3 and SO2 standard gases. Both standard gases were bubbled through a 0.5% boric acid solution independently and simultaneously; 0∼200 times as much SO2 as NH3 by mole was bubbled through a boric acid solution. The absorbed NH3 and SO2 were determined by coulometry and alkalimetry, respectively. The magnitude of interference was dependent upon the amount of SO2 absorbed in the boric acid solution, not the molar ratio of SO2 to NH3. More than 100 μmol SO2 led to a serious decrease in the absorbance. In the case of a 20 liter sample, it was found that more than approximately 110 volppm of SO2 gave a lower analytical value of NH3. The interference could be eliminated by bubbling 400 ml of oxygen at a flow rate of about 70 ml min-1 through a boric acid solution containing the absorbed gas sample.