Table 1.

Apparent association constant (Ka) between FQ and cations.

	CIP–Cations (M−1, 1:1 Complexes) [31]	LVX-cation (M−2, 2:1 Complexes) [32]
Ca2+	100	562
Fe2+	122 *	34,673
Mg2+	720	4898
Fe3+	1551 *
Zn2+	2700	27,542
Al3+	88,000
Cu2+	906,900

* unpublished data.