Ultrahigh sensitivity nitrogen-doping carbon nanotubes-based metamaterial-free flexible terahertz sensing platform for insecticides detection

With the rapid advances in terahertz (THz) spectroscopy, metamaterial-free THz sensors have been of importance due to efficient cost, high sensitivity and overcoming the limited tunability of the optical constants of metals. Here, a metamaterial-free and flexible THz sensor based on nitrogen-doping carbon nanotubes (N-CNTs) coupled with signal-enhancing Au NPs was proposed for detecting nereistoxin-related insecticides (NRIs). Sensitivity and selectivity for NRIs detection have been realized over the range of 3.3-100 μg/L with good linear fitting (R2 ≥ 0.9003) and LOD was 1.33 μg/L. Accuracy was validated by the recovery rates of 105.87-109.75% of NRI in spiked food-matrix sample. These results indicated the developed signal-enhancing THz method, validated by LC-MS/MS, exhibited high sensitivity and simplicity detection, which has noteworthy potential for applications in food safety and environment monitoring.