Amperometric biosensors based on LDH-ALGINATE hybrid nanocomposite for aqueous and non-aqueous phenolic compounds detection

摘要

To immobilize enzyme a new elegant approach based on layered double hydroxide-alginate hybrid nanocomposite (Zn2Al-Alg LDH) was developed for fabricating phenol biosensors. The alginate biopoly-mer was intercalated into the LDH structure by the direct coprecipitation method, and the resulting nanohybrid material was applied to entrap polyphenol oxidase (PPO). Interactions between PPO and LDH-Alg were characterized by PXDR, FT-IR and SEM. These biomembranes were stabilized by chemical cross-linking with glutaraldehyde (GA) or calcium complexation and subsequently were tested for the detection of phenol derivatives in Tris-HCl buffer (pH 7.0) and organic solvents. In aqueous medium, the best configuration was PPO/Zn2Al-Alg/GA which exhibited a very high sensitivity for cate-chol, namely 73.6 AM"1 cm"2 over a linear range between 2 x 10"9 and 3 x 10~5 M and with a detection limit of 0.5 nM. In chloroform, the PPO/Zn2Al-Alg/GA/Ca biomembrane had a linear response for catechol between 1 x 10~8 and 3 x 10"6 M with a sensitivity of 4.9 AM"1 cm"2 and a detection limit of 0.01 u,M.