What is the Difference Between Steady State and Time Resolved Fluorescence?

Steady-state fluorescence and time-resolved fluorescence are two different methods used to study fluorescence in samples. The main difference between these two methods lies in the nature and properties of the measurements:

• Steady-state fluorescence involves the study of long-term fluorescence, typically visible or near IR light, and is commonly used in excitation and emission scans, synchronous scans and maps, steady-state fluorescence anisotropy, and excitation-emission profiles.
• Time-resolved fluorescence (TRF) is monitored as a function of time upon excitation and is based on the detection of intensity decays and/or delayed emission signal upon excitation. TRF measurements allow for the study of the fluorescence lifetime and the relaxation time of the sample from the excited state to the steady state.

Time-resolved fluorescence has some advantages over steady-state fluorescence, such as reduced background noise and increased sensitivity. Additionally, large Stokes shifts in lanthanides used in time-resolved fluorescence greatly increase the signal-to-background ratio, further enhancing the detection sensitivity. Various techniques can be employed to obtain time-resolved fluorescence measurements, including fast-detection electronics, time-correlated single-photon counting, streak cameras, intensified CCD cameras, and optical gating.

Comparative Table: Steady State vs Time Resolved Fluorescence

Steady-state and time-resolved fluorescence are two types of fluorescence measurements that differ in the way they study the fluorescence properties of a sample. Here is a table summarizing the differences between them:

Steady-state fluorescence involves the study of long-term fluorescence properties, such as intensity and anisotropy, and is used in various applications like excitation/emission scans and synchronous scans. On the other hand, time-resolved fluorescence focuses on the short-term fluorescence properties, such as intensity decays and lifetimes, and is used for fluorescence lifetime measurements and anisotropy decays. Time-resolved fluorescence has the advantage of lower background noise and higher sensitivity compared to steady-state fluorescence.