Table 1.

Influence of pH on NH₃ and NH₄⁺ concentration

	NH3		NH4+
pH	Concentration, μmol/l	% Change	Concentration, μmol/l	% Change
5.00	0.071	−99.6%	999.9	1.8%
6.00	0.71	−96%	999.3	1.7%
6.50	2.22	−87%	997.8	1.6%
7.00	7.03	−60%	993.0	1.1%
7.20	11.1	−36%	988.9	0.6%
7.40	17.5	0%	982.5	0.0%
7.60	27.4	57%	972.6	−1.0%

Calculations were based upon solution with 1 mmol/l total ammonia and pK_a′ for NH₃ + H⁺↔NH₄⁺ buffer reaction of 9.15. The % Change columns reflect change from pH 7.40.