Table 3.

Global multi-exponential analysis of the intensity decay of Quin–2.^a

τ1 = 0.62 ns		τ2 = 1.31 ns		τ3 = 10.40 ns		${\chi }_{\mathrm{R}}^2=3.2$
< τ1 = 0.54 ns		τ2 = 1.32 ns		τ3 = 10.32 ns		${\chi }_{\mathrm{R}}^2=3.0>$b
[Ca2+] nm	α1c	α2	α3	f1	f2	f3	$\overline{\tau }(ns)$
8	0.402	0.540	0.058	0.160	0.452	0.388	4.60
	< 0.579	0.391	0.030	0.276	0.455	0.269	3.45 >
38	0.328	0.381	0.290	0.055	0.136	0.811	8.47
	<0.481	0.419	0.089	0.153	0.318	0.529	5.82 >
100	0.129	0.365	0.505	0.014	0.082	0.904	9.45
	<0.608	0.270	0.122	0.170	0.184	0.646	7.02 >
602	0.010	0.192	0.798	0.001	0.029	0.970	10.07
	<0.544	0.276	0.180	0.117	0.145	0.738	0.786 >

^aIn buffer at pH 7.2, 20°C, 343 nm excitation, emission observed through a Coming 3-75 filter

^bThe numbers in angular brackets are after 20 min of focused illumination (60–70% photobleaching)

^cThe intensity decays were fit to the multi-exponential model, $\mathrm{I}(\mathrm{t})=\Sigma {\alpha }_{\mathrm{i}}{\mathrm{e}}^{-\mathrm{t}∕\eta }$. The fractional intensity of each component is give by ${\mathrm{f}}_{\mathrm{i}}=\frac{{\alpha }_{\mathrm{i}}{\tau }_{\mathrm{i}}}{\Sigma {\alpha }_{\mathrm{j}}{\tau }_{\mathrm{j}}}$; The following values were obtained for a global double exponential fit: τ₁ = 1.02 ns; τ₂ = 10.31 ns; ${\chi }_{\mathrm{R}}^2=5.1$; < τ₁ = 0.83 ns; τ₂ = 9.69 ns; ${\chi }_{\mathrm{R}}^2=12.0>$