水溶液中的铵离子是极弱酸(k_a=5.6×10~(-10)),很难用经典酸碱滴定或pH滴定法直接测定。目前虽有线性滴定法可用,但需涉及较烦杂的计算。 Bela Noszal等用独特的pH滴定法,直接测定极弱碱SO_4~(2-)离子获得成功。据此,我们探索了用pH滴定法直接测定铵盐,取得较满意的结果,其原理如下: The ammonium ion in aqueous solution is a very weak acid (k_a = 5.6 × 10 -10), which is hard to be directly measured by classical acid-base titration or pH titration. Although linear titration is currently available, more complicated calculations are required. Bela Noszal and other unique pH titration, direct determination of very weak base SO_4 ~ (2) ions were successful. Accordingly, we explored the use of pH titration direct determination of ammonium salt, to obtain more satisfactory results, the principle is as follows: