A time-gated fluorescence detector using a tuning fork chopper.

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Materials Science

Background:

• Measuring long-lifetime fluorescent compounds often requires expensive gated detection systems.
• Conventional systems can suffer from sensitivity loss due to photocathode fatigue.

Purpose of the Study:

• To develop an affordable and robust fluorescence detection system.
• To measure long-lifetime fluorescent compounds using a novel gating mechanism.

Main Methods:

• A tuning fork chopper was employed to block excitation pulses and short-lived fluorescence.
• An inexpensive, conventional photosensor module was used for luminescence signal collection.
• The terbium(III)-dipicolinic acid (DPA) chelate was used as a model long-lifetime fluorophore.

Main Results:

• The system achieved a limit of detection (LOD) of 120pM for DPA.
• The developed system is significantly less expensive than electronically gateable phototomultiplier tubes (GPMTs).
• The system showed no signs of sensitivity degradation over time, unlike GPMTs.

Conclusions:

• An affordable and sensitive gated fluorescence detection system was successfully demonstrated.
• The tuning fork chopper provides a cost-effective gating solution for long-lifetime fluorescence measurements.
• This approach offers a stable and economical alternative for various analytical applications.