Highly sensitive electrochemical detection of gallic acid in tea samples by using single-walled carbon nanotubes@silica dioxide nanoparticles decorated electrode

In this work, a simple and efficient gallic acid (GA) electrochemical sensor was successfully fabricated by using silica dioxide (SiO2) nanoparticles@single-walled carbon nanotubes (SWCNT) nanocomposite modified glassy carbon electrode (SWCNT@SiO2/GCE). The SWCNT@SiO2/GCE sensor was applied for the highly sensitive electrochemical detection of GA for the first time. For the SWCNT@SiO2 nanocomposite, SWCNT with interconnected carbon conductive network possessed high conductivity property, large specific area, and efficient charge transport channels. The abundant hydroxyl groups and silanol groups on the surface of SiO2 nanoparticles were good for the enrichment of GA molecules on the surface of SWCNT@SiO2/GCE. Moreover, SWCNT could greatly compensate for the non-conductivity of SiO2 nanoparticles. The synergistic effect of SWCNT and SiO2 nanoparticles enhanced the electrochemical determination performance of GA. The SWCNT@SiO2/GCE sensor exhibited good GA determination performance (pH=2.0, linear GA concentration: 0.03–20 μM, limit of detection: 8.05 nM). The fabricated sensor also showed good reproducibility, reproducibility, and anti-interference performance. In addition, the SWCNT@SiO2/GCE sensor presented good practical application performance for the detection of GA in tea samples (Recovery rate: 95.2–103.6%; relative standard deviation: 2.03–4.50%). This work exhibits a novel approach for the sensitive determination of GA in green tea and black tea samples.