(a) The first and second crossover time (t_cr1, t_cr2) each as a function of mobile buffer concentration at three different concentrations of calcium ions: [Ca²⁺]₀ = 6.23,31.15,62.3 nM (note the overlap of data points for different values of [Ca²⁺]₀), for k⁺ = 1 and k⁻ = 2.6. The upper inset in panel (a) shows the intersections of the lines yielding the crossover times, t_cr1 and t_cr2. The lower inset shows α_ins for different values of [Ca²⁺]₀. (b) The calcium half-life obtained from Eq. (10) at the same [Ca²⁺]₀ as that in panel (a). (c) Plots of t_cr1 and t_cr2 in comparison to t_hl obtained from the analytic solution in Eq. (10).