Adaptive and sensitive fibre-optic fluorimetric transducer for air- and water-borne analytes

Publication date: Available online 12 February 2019

Source: Talanta

Author(s): Alhulw H Alshammari, Abraham Kirwa, Alan Dunbar, Martin Grell

Abstract

A sensitive fibre optic fluorescence intensity meter has been designed and built as a transducer to detect quenching of conjugated polymer fluorescence with minimum adjustment between air- and waterborne analytes. Only generic, commercially available parts including optical fibres, solvents, airbrush, standard optical and electronic parts, and a digital lock-in amplifier have been used, avoiding the need for a fluorescence spectrometer. To test the instrument, optical fibres were sensitised with the generic fluorescent poly(phenylene-vinylene) derivative MDMO-PPV and exposed to a variety of vapour pressures, and concentrations in water, of the nitroaromatic explosive 2,4 dinitrotoluene (DNT). We establish dimensionless Stern-Volmer constants (K_SV) and limit-of-detection (LoD) for air- and water-borne DNT as K_SV(air) = 1.4 ×10⁷vs. K_SV(water) = 5.8 ×10⁶ and LoD(air) = 10.9 ppb and LoD(water) = 56 ppb. These LoDs compare favourably to prior reports. We consider our study of the MDMO-PPV / DNT system as a successful test of our transducer design and recommend its wider use.

Graphical abstract

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