Rapid, Quantitative Measurements Using Time-Correlated Single-Photon Counting and Time-Filtered Detection

Abstract

One-second quantitative measurements are achieved by employing time-correlated single-photon counting detection and a software time-filter for signal-to-noise ratio enhancement. Fast collection times are accomplished by configuring a commercial time-to-amplitude converter in the reverse-interactive mode. In such a configuration, instrumental sensitivity is enhanced sixfold over that for the conventional-noninteractive configuration, and photon-processing rates can be as high as 125 kHz. The linear range for the one-second measurement is greater than three orders in magnitude, the sensitivity is 4.6 × 1014 counts M−1 s−1, and the extrapolated lower limit of detection for solutions of β-carboline in 0.5 M sulfuric acid is about 2 × 10−13 M.