Electrochemical Behavior of Quinoxalin-2-one Derivatives at Mercury Electrodes and Its Analytical Use

Table 1

Comparison of spectrophotometrically and polarographically determined dissociation constants (derived from dependencies 𝐸_1/2 = f(pH) at ionic strength of 0.15).

Compound	Polarography					Spectrophotometry
	𝑝𝐾Ox1	𝑝𝐾Ox2	𝑝𝐾𝑅1	𝑝𝐾𝑅2	𝑝𝐾𝑅3	𝑝𝐾𝑂𝑥1
I	9.9	—	2.7	7.6	—	9.85 (λ 286 nm)
II	9.8	—	2.0	8.0	—	10.04 (λ 300 nm)
III	5.2	10.1	1.9	~5.5	8.5	—