Horseradish peroxidase biosensor based on a MWCNTs/black phosphorene nanocomposite for sensitive electrochemical detection of trichloroacetic acid and nitrite

Abstract

Developing electrochemical biosensors to detect trichloroacetic acid (TCA) and nitrite (NaNO₂) helps address serious health risks by improving electron transfer in the enzyme’s active center, enabling accurate monitoring of these harmful substances in environmental and food safety applications. Herein, a novel electrochemical horseradish peroxidase (HRP) biosensor was fabricated by immobilizing on a multi-walled carbon nanotubes-black phosphorene (MWCNTs-BP) nanocomposite modified carbon ionic liquid electrode. The structure and enzyme interaction were characterized using SEM, TEM, FT-IR, and UV-Vis spectroscopy. The MWCNTs-BP composite enhances electron transfer and interfacial conductivity, enabling efficient direct communication between HRP and the electrode. Under optimal conditions, the biosensor exhibited excellent sensitivity for TCA and NaNO₂ detection with linear ranges of 3.0–558.0 mmol/L (LOD as 1.0 mmol/L) and 0.1–13.6 mmol/L (LOD as 0.03 mmol/L), respectively. It was successfully applied to detect TCA and NaNO₂ in medical facial peel solutions and pickled vegetable soaking water samples, respectively, demonstrating strong practical applicability.