Alizarin Red S Immobilized Acrylic Microspheres Film for Optical Fluorescence Sensing of Boric Acid

An optical microsensor for the quantification of boric acid in food samples has been developed based on poly(n- butyl acrylate) [poly(nBA)] microspheres film. Optical characterization of the immobilized alizarin red S (ARS) reagent on the polyacrylate microspheres film with boric acid has been performed via a fluorescence transduction approach. The ARS reagent was physically adsorbed on the hydrophobic acrylic microspheres film to form a chelating micropolymer with the support of a sol-gel matrix to prevent the leaching of the water-soluble ARS molecules. The immobilized ARS chelator on the poly(nBA) microspheres film afforded a quick optical sensing response within 1 min. A useful dynamic linear response range of the optical microsensor was established between 1.6 & mu;M and 32.0 & mu;M boric acid with a limit of detection (LOD) obtained at 1 & mu;M. The acrylic micropolymer-based fluorescence boric acid sensor yielded promising reproducibility resullts with relative standard deviation (RSD) values attained in the range of 3.3-3.6%. The developed optical chemical microsensor has been applied for fluorescence quantitation of boric acid in yellow noodle and flat rice noodle ('hor fun'/'kway teow') samples, and exhibited no significant disagreement compared with traditional inductively coupled plasma-optical emission spectrometry (ICP-OES) reference method.

Automated summary

An optical microsensor based on poly(n- butyl acrylate) microspheres film was developed for the quantification of boric acid in food samples. The immobilized alizarin red S reagent on the polyacrylate microspheres film was characterized using fluorescence transduction. The developed microsensor showed a quick optical sensing response, a useful dynamic linear response range, and promising reproducibility results.