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EP-4735872-A2 - WAVEGUIDE INTERFEROMETER SENSING LAYER COMPOSITIONS FOR FLUORO-CONTAINING SUBSTANCES AND RELATED METHODS

EP4735872A2EP 4735872 A2EP4735872 A2EP 4735872A2EP-4735872-A2

Abstract

A sensing layer composition is provided. The sensing layer composition is particularly suited to be adhered to at least one side of one or more waveguide channels in/on a waveguide chip of an interferometric system. The sensing layer composition is adapted to bind or be selectively disturbed by one or more fluoro-containing substances via optical interferometric analysis.

Inventors

  • XU, JIE

Assignees

  • Georgia Tech Research Corporation

Dates

Publication Date
20260506
Application Date
20240809

Claims (10)

  1. 1 . A sensing layer composition comprising : a silane mixture comprising: one or more fluoro-containing silanes; and optionally, tetramethoxysilane. wherein the sensing layer composition is adapted to be adhered to at least one side of one or more waveguide channels in/on a waveguide chip of an interferometric system, and wherein the sensing layer composition is adapted to bind or otherwise be selectively disturbed by one or more analytes.
  2. 2. The sensing layer composition of claim 1 , wherein the interferometric system is an optical interferometric system.
  3. 3. The sensing layer composition of claim 1 , wherein the sensing layer composition is formulated as a fluorinated film.
  4. 4. The sensing layer composition of claim 1 , wherein the sensing layer composition relies on noncovalent interactions that occur between highly fluoro-containing substances for binding and detection of one or more analytes.
  5. 5. The sensing layer composition of claim 1 , wherein the one or more analytes that may be detected include at least one fluoro-containing substance.
  6. 6. The sensing layer composition of claim 1 , wherein the one or more analytes includes perfluoroalkyl, polyfluoroalkyl substances (PFAS), or a combination thereof.
  7. 7. The sensing layer composition of claim 6, wherein the polyfluoroalkyl substances (PFAS) is selected from the group consisting of perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorononanoic acid (PFNA), hexafluoropropylene oxide dimer acid (HFPO-DA), perfluorohexane sulfonic acid (PFHxS), and perfluorobutane sulfonic acid (PFBS).
  8. 8. The sensing layer composition of claim 1 , wherein the one or more fluoro-containing silanes is present in the silane mixture in an amount of at least about 0.1% w/w based on the total weight of the silane mixture.
  9. 9. The sensing layer composition of claim 1 , wherein the silane mixture optionally includes tetramethoxysilane in an amount of at least about 0.1 % w/w to about 50% w/w based on the total weight of the silane mixture.
  10. 10. The sensing layer composition of claim 1 , wherein the silane mixture includes from about 20% w/w to about 80% w/w of one or more fluoro-containing silanes and from about 20% w/w to about 80% w/w tetramethoxysilane based on the total weight of the silane mixture.

Description

WAVEGUIDE INTERFEROMETER SENSING LAYER COMPOSITIONS FOR FLUORO-CONTAINING SUBSTANCES AND RELATED METHODS BACKGROUND [0001] Fluoro-containing substances such as perfluoroalkyl and polyfluoroalkyl substances (PFAS) are a group of synthetic chemicals that have received significant public attention. Fluoro-containing substances have been used in industry and consumer products worldwide since the 1950’s. Fluoro-containing substances such as PFAS are extremely persistent chemicals that are widely distributed in the environment as a result of extensive use in applications including fluoropolymer manufacturing, food packaging, lubricants, water-resistant coatings, and aqueous fire-fighting foams. Current scientific research suggests that exposure to high levels of certain PFAS may lead to adverse health outcomes. Due to numerous exposures and their adverse health impacts, legislation has been proposed that provides $10 billion in funding to specifically address PFAS and other emerging contaminants in water. [0002] The United States Environmental Protection Agency (EPA) has proposed National Primary Drinking Water Regulation (NPDWR) for six PFAS including perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorononanoic acid (PFNA), hexafluoropropylene oxide dimer acid (HFPO-DA, commonly known as GenX Chemicals), perfluorohexane sulfonic acid (PFHxS), and perfluorobutane sulfonic acid (PFBS). The proposed Maximum Contaminant Level (MCL) is 4.0 parts per trillion (ppt) for both PFOA and PFOS. The proposed rule would require public water systems to monitor the levels of PFAS on a regular basis. [0003] The current EPA methods 533 and 537.1 start with a polystyrene-divinylbenzene (SDVB) solid-phase extraction (SPE) step to concentrate the sample, followed by an LC-MS/MS analysis. Both methods can reliably measure and quantify the six PFAS at or below their proposed MCLs. While the instrumental methods are sensitive and effective, the high instrument cost and the requirement of a laboratory with trained personnel, a turnaround time of weeks for a testing result are prohibitive in routine monitoring and do not allow for widespread sampling and testing of common PFAS. [0004] Several sensor platforms have been reported for PFAS measurement including metal-organic framework-based impedance sensors for PFOS analysis and voltammetry based PFOA sensors using the selective ionomer coated electrodes. Colorimetric based testing kits have been developed based on the ion-pair between the cationic surfactant with PFAS. Amplifying fluorescent polymers (AFPs) have been reported to selectively detect aqueous PFOA and PFOS. The AFPs are highly fluorinated with poly(p-phenylene ethynylene) and polyfluorene as backbones. [0005] In sum, challenges associated with existing sensor systems include: (a) sensitivity; (b) selectivity; (c) portability; and (d) requirements of the target sample preparation. Additionally, known sensors struggle to provide selective analysis towards the various PFAS structures that span a variety of chain lengths and head groups based on standard LC-MS based methods. Thus, there exists a need for field-usable waveguide interferometry sensing layer compositions that are useful for a wide variety of fluoro-containing substances. SUMMARY [0006] A sensing layer composition is provided. The sensing layer composition is particularly suited to be adhered to at least one side of one or more waveguide channels in/on a waveguide chip of an interferometric system. According to a particular embodiment, the sensing layer composition is adapted to bind one or more analytes that are detected via interferometric analysis. [0007] According to a particular embodiment, the sensing layer composition includes an organic substrate tagged with a perfluoroalkyl moiety. Such a design enables the selective separation of a tagged species from other mixture components by solid phase extraction over fluorous-functionalized silica. [0008] According to one embodiment, the sensing layer composition includes a silane mixture. According to one embodiment, the silane mixture may include one or more fluoro- containing silanes. Suitable fluoro-containing silanes include, but are not limited to, the following: heptadecaf luoro-1 , 1 , 2, 2-tetrahydrodecyl-trimethoxysilane; tridecafluoro-1 , 1 , 2, 2- tetrahydrooctyl-trimethoxysilane; nonafluorohexyltrimethoxysilane; and tetramethoxysilane. Fluorine containing polymers, such as polytetrafluoroethylene (Teflon), may also be used. According to one embodiment, the silane mixture includes tetramethoxysilane to control surface density of fluoro-contained silane. [0009] According to one embodiment, the one or more fluoro-containing silanes are present in the silane mixture in varying amounts and ratios. According to one embodiment, the number of -CF2- groups in the fluoro-containing silanes may vary. According to one embodiment, the number of -CF2- groups in the fluoro-containing silanes