In fluorescence quenching expt of my probe with BSA with increasing temperature the Ksv and Kq values are decreasing whereas, in time resolved measurements first lifetime component is decreasing to an appreciable extent but the second lifetime component is barely altered. Moreover, the plot of tau0/tau vs [probe] is linear to some extent but is exhibiting an upward deviation towards the y-axis at higher [probe]
Hi, you did not mention what type of probe you are using with BSA. At low concentration of probe. there should be a dynamic quenching with increasing temperature as the probe and quencher are not coming get closer (may be you use low concentration of BSA). if you use higher concentration of BSA you can see the upward curve. This should reflect the high lifetime species.
I'm not sure whether I understand completely, but I will try to give some general remarks, which you probably already are aware of(: The decrease of Kq with increasing temperature is usually observed in case of static quenching, because the complex probe-quencher is less stable. On the other hand, Kq is usually expected to rise with increasing temperature in case of dynamic quenching (e.g. due to increased mobility of the molecules). The decrease of lifetime of one component with increasing [quencher] or T indicates that this component corresponds to dynamic quenching. The component whose lifetime is not altered with increased [quencher] may correspond to static quenching or to a probe population which is somehow shielded from the quencher. Therefore, is is possible that both type of quenching take place. Regarding the plot of tau0/tau vs [probe], I would indeed expect this to have a quadratic component (and therefore exhibiting upward deviation) - when the probe quenches itself, then the quenching rate should be second order in [probe], or am I mistaken??
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