(top) Absorption spectra of L3:2•Zn(NO3)2 complex (20 μM) showing complete conversion to L3 upon addition of two molar equivalents of EDTA in water/methanol (4:1 volume ratio). (a) L3:2•Zn(NO3)2 with no EDTA, (b) L3:2•Zn(NO3)2 plus 0.5 equiv. EDTA, (c) L3:2•Zn(NO3)2 plus 1.0 equiv. EDTA, (d) L3:2•Zn(NO3)2 plus 2.0 equiv. EDTA, (e) L3. (bottom) Absorption spectra of L3:2•Zn(NO3)2 complex (20 μM) in the presence of Na4PPi (40 μM) is unchanged by the addition of one hundred molar equivalents of EDTA in water/methanol (4:1 volume ratio). (a) L3:2•Zn(NO3)2 plus Na4PPi, (b) L3:2•Zn(NO3)2 plus Na4PPi and 100 equiv. EDTA, (c) L3.