Radiometric determination of stability constants of mercury species complexes with L-cysteine

Liquid-liquid distribution method has been applied for the determination of the composition and stability constants of mercury species with L-cysteine /H₂L/. In the pH range 2–8, mercury /II/ forms a complex Hg/HL/₂ with very high stability constant /lg ₂ = 40.0/, whereas methylmercury and phenylmercury form complexes CH₃HgHL /lg ₁ = 15.56/ and C₆H₅HgHL /lg ₁ = 16.5/. At pH13, anionic complexes HgL₂^2– /lg ₂ = 42.7/, CH₃HgL^– /lg ₁ = 16.58/ and lg ₁ = 17.7 are formed.