Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE This study prepared two types of nanofiber test strips through physical doping and chemical grafting. They exhibit excellent specificity and sensitivity toward HSO3
− with detection limits of 1.51 × 10−4 mol L−1 and 2.37 × 10−5 mol L−1, respectively, making them suitable for food and pharmaceutical testing.

ABSTRACT
Sulfites and bisulfites in foods pose health risks, which drives the demand for effective sensing materials. This study fabricates two types of polymer-based nanofiber test strips through physical doping and chemical grafting of a fluorescent probe (ISEV-Indole Sulfonate Ethyl Vanillin) into poly(4-vinylpyridine) (P4VP). The resulting materials, denoted P4VP NFTP@ISEV and P4VP-ISEV NFTP, benefit from the high surface area of electrospun nanofibers and the specific molecular recognition capability of the probe. Both strips exhibit high specificity and sensitivity toward HSO3
−, showing a dual-wavelength fluorescence response characterized by a decrease at 600 nm and an increase at 460 nm. The detection limits are determined to be 1.51 × 10−4 mol L−1 and 2.37 × 10−5 mol L−1, respectively, with minimal interference from common anions or thiols observed. The strips are successfully applied to detect HSO3
− in real food and pharmaceutical samples, which demonstrates the potential of functional polymer nanofibers as practical sensing platforms for anion detection.