Mid-infrared sensor for hydrocarbon monitoring: the influence of salinity, matrix and aging on hydrocarbon–polymer partitioning

Abstract

Mid-infrared sensors based on ATR spectroscopy provide a robust and reliable platform for the quantification of organic molecules dissolved in water.

Block Copolymer-Coated ATR-FTIR Spectroscopic Sensors for Monitoring Hydrocarbons in Aquatic Environments at High Temperature and Pressure

“…Although the MIR-ATR sensor has been extensively used to quantify a range of different hydrocarbons in water at ambient conditions, real-world applications still pose several potential challenges. The effect of sample matrix and salinity was examined in a previous paper where saline water gave an enhanced response due to higher hydrocarbon partitioning into the polymer film . In addition, we have found that pressure changes do not significantly affect sensor response; however, elevated temperatures remain a challenge .…”

“…The effect of sample matrix and salinity was examined in a previous paper where saline water gave an enhanced response due to higher hydrocarbon partitioning into the polymer film. 12 In addition, we have found that pressure changes do not significantly affect sensor response; however, elevated temperatures remain a challenge. 27 This paper aims to investigate and develop a new class of polymers for use as sensor materials at high temperatures.…”

“…Mid-infrared attenuated total reflectance (MIR-ATR) spectroscopy has received much attention as a sensor platform for the identification and quantification of hydrocarbons in water . A polymer membrane is usually applied to the surface of a MIR transparent optical waveguide material (i.e., ATR crystal and optical fiber), and this is then exposed to a solution comprising the hydrocarbon analyte (Figure a).…”

“…Mid-infrared attenuated total reflectance (MIR-ATR) spectroscopy has received much attention as a sensor platform for the identification and quantification of hydrocarbons in water. 12 A polymer membrane is usually applied to the surface of a MIR transparent optical waveguide material (i.e., ATR crystal and optical fiber), and this is then exposed to a solution comprising the hydrocarbon analyte (Figure 1a). The polymer used is typically hydrophobic/lipophilic which performs several roles including (1) enrichment or extraction of low-polarity molecules into the polymer and the region of the evanescent field and (2) exclusion of water and other interfering molecules from the evanescent field.…”

Integrated Nanophotonic Waveguide-Based Devices for IR and Raman Gas Spectroscopy

“…Polymers have been widely used due to simple processing, availability, tuneability (functional groups, molecular weight, ramification, backbone structure, or crosslinking degree), and their behaviour as extraction materials, with their enrichment properties mainly dependent on their polarity, free volume, pore size, and pore distribution [101]. A great variety of polymeric materials have already been investigated, including polyisobutylene [102], ethylene/propylene copolymer [103], low-density polyethylene [104], Teflon ® AF [105], poly(dimethylsiloxane) [106,107], poly(acrylonitrile-co-butadiene) [107], poly(styrene-cobutadiene) [107], poly(vinyl chloride) [108], polystyrene, and poly(methyl methacrylate) [83,109,110]. Among these, fluorinated polymers have shown good transparency up to MIR wavelengths due to the substitution of C-H bonds, high free volume, and outstanding thermal and mechanical properties [57].…”