In Situ Synthesis of Plasmonic Core MIPs on U Bend Optical Fibers for LSPR Sensing of Small Molecule Contaminants in Food and Environment: An Illustration With Bisphenol A

Detection and remediation of emerging water contaminants such as active pharmaceutical ingredients, endocrine disrupting compounds (EDCs), and polyaromatic hydrocarbons is a global challenge. The current study reports a label-free and biorecognition element-free detection strategy for the detection of such organic compounds in aqueous specimens with Bisphenol A (BPA) as a model analyte. A novel in situ molecular imprinting technique on gold nanoparticles (AuNPs), immobilized on U-bend optical fibers is demonstrated for localized surface plasmon sensing. The molecularly imprinted polymer film was directly formed on allyl mercaptan-modified gold nanoparticles. With an optimized ratio of 1:12:20 of the template: monomer: crosslinker, the sensor could detect BPA in the linear range from 30 ng/mL to
$10 ~\mu \text{g}$
/mL (
${R}^{{2}}$
= 0.95) in deionized water and from 50 ng/mL to
$50 ~\mu \text{g}$
/mL (
${R}^{{2}}$
= 0.96) in bottled and canned soft, alcoholic and aerated beverages, fruit juices and ice tea with negligible cross sensitivity from possible interferents. This technology is thus of utility to analyze BPA, and similar organic molecules in wastewater, food, and beverages and indicate the fitness of food and water for human consumption.