Application of time-correlated single photon counting and stroboscopic detection methods with an evanescent-wave fibre-optic sensor for fluorescence-lifetime-based pH measurements

Abstract

Quasi-distributed optical fibre sensor arrays containing luminescent sensor molecules can be read out spatially resolved utilizing optical time-of-flight detection (OTOFD) methods, which employ pulsed laser interrogation of the luminosensors and time-resolved detection of the sensor signals. In many cases, sensing is based on a change in sensor luminescence intensity; however, sensing based on luminescence lifetime changes is preferable because it reduces the need for field calibration. Because in OTOFD detection is time-resolved, luminescence-lifetime information is already available through the signal pulses, although in practise applications were restricted to sensors with long luminescence lifetimes (hundreds of ns). To implement lifetime-based sensing in crossed-optical-fibre-sensor arrays for sensor molecules with lifetimes less than 10 ns, two time-domain methods, time-correlated single photon counting and stroboscopic detection, were used to record the pH-dependent emission of a fluorescein derivative covalently attached to a highly-porous polymer. A two-term nonexponential decay function yielded both a good fit for experimental lifetime data during reconvolution and a pH response that matches Henderson–Hasselbalch behaviour, yielding a sensor accuracy of 0.02 pH units. Moreover, strong agreement was obtained for the two lifetime determination methods and with intensity-based measurements taken previously.

Study of laser-induced chlorophyll fluorescence lifetime measurement and its correction

“…(8) shows that the small error will be amplified to produce a serious accumulative error of g(n). The reason is as follows.…”

“…The data fitting method and pulse delay method are unable to make use of the whole fluorescence information, and thus the measurement precision is seriously affected; the Fluorescence Lifetime Imaging Microscopy (FLIM) technique must be fitted with a complicated ICCD, and this technique has a limited detection scope [6][7][8][9]. The time-resolved method is one of the primary ways for photobiology and photochemistry which used to employ on the fast-changing signals [10][11][12][13].…”

Development of microscopic time‐domain dual lifetime referencing luminescence detection for pH monitoring in microfluidic free‐flow isoelectric focusing

“…A problem of lifetime-based pH sensing is the short lifetime of most pH probes in the nanosecond range. The instrumental demands and costs for such lifetime measurements are very elevated compared to the detection of lifetimes in the micro-and millisecond range [22]. Huber …”

“…A problem of lifetime-based pH sensing is the short lifetime of most pH probes in the nanosecond range. The instrumental demands and costs for such lifetime measurements are very elevated compared to the detection of lifetimes in the micro-and millisecond range [22]. Huber et al invented a novel technique for luminescence decay time referencing in frequency domain, termed dual lifetime referencing (DLR) [23].…”

An Optical Fiber-Based Sensor Array for the Monitoring of Zinc and Copper Ions in Aqueous Environments

“…In previous research, we demonstrated an optical fiber design utilizing two optical fibers arranged orthogonally to each other, referred to as a crossed-fiber sensor array [24]. An example of this design is shown in Figure 1.…”