Table II.

Dissociation Constants (mM) Determined from Intensity and from Phase-Modulation Measurements for Magnesium Probes

Probe	Intensity method		Ref. No.	Phase-modulation method
	KD (Mg)	KD (Ca)		${K_{\text{D}}}^{\text{θ}}(\text{Mg})$	${K_{\text{D}}}^{\text{m}}(\text{Mg})$
mag-fura-2	1.5	—	10	Insufficient lifetime sensitivity
	2.7	0.030	38
	2.3	—	24
mag-indo-1	2.7	—	10	Insufficient lifetime sensitivity
	3.1	0.034	38
mag-fura-5	2.6	0.0065	10	Insufficient lifetime sensitivity
mag-fura-red	4.6	0.017	32	Insufficient lifetime sensitivity
MgO	3.5	0.012	32	Not measured
mag-quin-2	0.8	—	10			Excitation (nm)
	2.2	—		0.30	0.07	343
				0.35	0.09	345
				0.85	0.15	350
				2.7	0.55	355
				10.1	1.5	360
				45	6.5	365
				>100	~20	370
mag-quin-1	6.7	—	10	1.3	—	343
MgO	0.9	0.0048	10			Frequency (MHz)
	1.4	—		0.27	0.09	75.9
				0.45	0.11	151.0
				0.68	0.20	759.0