A ratiometric electrochemical sensing strategy based on the self-assembly of Co NC/CNT and methylene blue for effective detection of the food additive tert-butylhydroquinone

It is crucial to achieve accurate and rapid detection of tert-butylhydroquinone (TBHQ) in the field of food safety, for the excessive addition of TBHQ in food is harmful to human health and evil to the environment and aquatic life. Therefore, researchers have done a lot of work on signal amplification through nanomaterials to achieve TBHQ detection, but the conventional single-signal detection strategy results in limited accuracy. In this work, an innovative and facile ratiometric electrochemical sensor for TBHQ detection was built based on advanced nanomaterial complexes carbon nanotube-encapsulated Co/nitrogen-doped carbon (Co NC/CNT) and selected internal reference signal methylene blue (MB) enhancing the accuracy by offering effective self-calibration. A linear relationship between the net peak current ratio between TBHQ and MB (ΔI (TBHQ)/ΔI (MB)) and the TBHQ concentration was obtained under the optimal experimental conditions, with two linear ranges of 0.1-20 μM and 20-100 μM and a limit of detection (LOD) of 0.054 μM (S/N = 3). Benefiting from the synergistic effects between Co NC and CNT and the ratiometric sensing strategy, the as-designed sensor for TBHQ detection showcased excellent selectivity, repeatability, reproducibility, stability, and satisfactory applicability in real edible oil samples.