β-Cyclodextrin-encapsulated and Ketjenblack carbon-embedded helical multi-walled carbon nanotubes networks: A synergistic signal amplification strategy for electrochemical sensing analysis of gallic acid

In this work, an ultrasensitive gallic acid (GA) electrochemical sensor was developed by using β-cyclodextrin-encapsulated and Ketjenblack carbon-embedded helical multi-walled carbon nanotubes (β-CD/HMCT/KC) networks, which were prepared by using ultrasound assisted one-pot strategy. β-CD not only achieved the good adsorption and enrichment‌ of GA‌ through ‌host-guest inclusion interactions but also promoted the ‌uniform dispersion‌ of HMCT and KC. HMCT facilitated the rapid electron transport through continuous tube-wall bending pathways, and the unique helical morphology further increased the surface corrugation, significantly enhancing the density of active sites. KC with ‌branched-chain morphology enabled the formation of branched-chain-like conductive carbon networks‌. The electrochemical performance of β-CD/HMCT/KC modified sensor was performed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). The ‌multifunctional integration‌ of β-CD/HMCT/KC enhanced the sensitivity of GA electrochemical analysis (Limit of detection: 8.8 nM, limit of quantification: 29.33 nM, linear concentration range: 0.5–20 μM). The practical evaluation of GA detection in food samples (teas and fruit juices) showed good recoveries of 96.03–104.37 % and low relative standard deviations of 2.30 %–4.57 %.