(17(2):49-50)Determination of Nitrate by Microdiffusion

Conway氏的擴散法在大量樣本的銨態氮定量上確有很多的幫助，如果用簡單的方法能把硝酸態氮還原成銨，則擴散法必為硝酸態氮定量的良法。Conway氏曾使用Devada合金以達此目的。亦有用硫酸鈦的方法，前者有產生氫氣之缺點，後者適當的試藥難以獲得。筆者曾用鋅粉及硫酸第一鐵為還原劑，而得良好的結果，故提供大家參考。 此法應用於低濃度之試液甚理想，較其他比色法為簡便，對較濃之試液亦可應用自如。 Zinc powder and ferrous sulphate are used as reducing agents for the determination of nitrate by microdiffusion. The ammonia is absorbed in boric acid acid titrated with 0.002N acid. No hydrogen is evolved as in using Devada alloy. The method is simple and suitable for the solution of low concentration ( 1 to 6 ppm of nitrogen using 30 ml of sample solutin). The recovery is about 96%