A selective optical chemical sensor for 2,6-dinitrophenol based on fluorescence quenching of a novel functional polymer

Abstract

A bifurcated optical fiber based chemical sensor for continuous monitoring of 2,6-dinitrophenol (2,6-DNP) has been proposed based on the reversible chemical reaction between a novel functional poly(vinyl chloride) (PVC) as the sensing material and the analytes. The functional PVC (FPVC), containing a fluorescent curcumin moiety, was synthesized by the nucleophilic substitution of a fraction of the chlorine atoms bound to the PVC backbone by curcumin. When plasticized in a membrane of 5 m thickness, FPVC extracts 2,6-DNP from aqueous solution into the bulk membrane phase and reacts with the analyte to form a complex with low fluorescence efficiency through hydrogen bonding. Formation of the complex gave a significant fluorescence quenching which is suitable for signalling the occurrence of the host-guest interaction. At pH 3.50, the sensor exhibits a dynamic detection range from 2.5 × 10 −6 to 7.0 × 10 −3 mol L −1 with a limit of detection of 1.0 × 10 −6 mol L −1 . As 2,6-DNP can provide an optimal space geometry matches to the formation of hydrogen bonds, the sensor shows excellent selectivity for 2,6-DNP over other nitrophenols. The forward and reverse response time (t 95 ) of the sensor both was within 1 min. The repeatability, reproducibility, and lifetime of the sensor were also satisfied. The sensor was applied to determine 2,6-DNP in water samples successfully.

Fluorescence based explosive detection: from mechanisms to sensory materials

“…Lin et al used a fluorescent curcumin moiety as a 2,6-DNP binding site to substitute poly(vinyl chloride) (PVC) 20. 94 This curcumin-PVC conjugate showed better sensitivity and selectivity for explosive detection compared to PVC membranes with physically entrapped curcumin. 5 mm plasticized curcumin-PVC membrane exhibited an optimal sensing performance for 2,6-DNP at pH 3.5 with a LOD of 1.0 Â 10 À6 M. The selectivity for 2,6-DNP was originated from the space geometry matching between the quencher and the polymer to form a cyclic complex.…”

Luminescence Sensors Applied to Water Analysis of Organic Pollutants—An Update

“…An optic fiber-based chemical sensor based on poly(vinyl chloride) containing a fluorescent curcumin moiety (FPVC) was developed by Wang et al . for the determination of 2,6-DNP in water [88]. FPVC extracts 2,6-DNP from the aqueous solution into the bulk membrane phase, leading to a significant fluorescence quenching of the curcumin moiety.…”

Optical fiber based methodology for assessment of thiocyanate in seawater

“…Secondly, it is important to take into account the molecular interactions that occur between the analyte molecules and the polymeric film with consequent changes in the intensity of the light power guided through the OF. 27,28 When the analyte molecules contact with the polymeric film, the optical power intensity will vary proportionally to the amount of the analyte present. Without losing sight of the advantages of OF sensors, the aim of this work was to develop an OF based methodology for detection of thiocyanate in seawater samples.…”