A glassy carbon electrode modified with molecularly imprinted poly(aniline boronic acid) coated onto carbon nanotubes for potentiometric sensing of sialic acid

A potentiometric sensor for sialic acid (SA) was developed based on molecular imprinting technique. The sensor was fabricated by modifying carbon nanotubes (CNT) and an SA-imprinted poly(aniline boronic acid) (PABA) film on a glassy carbon electrode (GCE). The detection strategy capitalizes on the change of electrochemical potential resulting from boronic acid-SA interaction. The imprinted PABA combines the functions of SA-binding boronic acid groups and the imprinting effect, thus endowing it with both chemical and sterical recognition capability. The imprint factor (IF, compared to a non-molecularly imprinted polymer) is 1.74. The sensor can well differentiate SA from its analogs at physiological pH values and has a linear potentiometric response (R2 = 0.998) in 80 μM to 8.2 mM SA concentrations range with a detection limit of 60 μM (at S/N = 3). The sensor was applied to the determination of SA in serum samples and gave recoveries between 93% and 105%.