A Smart Portable Sensor With Ratio and Dual-Mode for In Situ Detection of Nicotine in Tobacco Leaves

A smart portable sensor with ratio and dual-mode for in situ determination of nicotine (NIC) in tobacco leaves was reported. Activated screen-printed carbon electrode (SPCE) was used as a sensing platform. Paracetamol (PA) was used as a ratiometric reference. Current and potential dual-signal output was applied as dual-mode. The scanning electron microscope, energy dispersive spectroscopy, cyclic voltammetry, electrochemical impedance spectroscopy, square-wave voltammetry, and NIC morphological fitting and theoretical calculation were used to study the sensor. Under the amperometric mode, the linear range of NIC is 10– $800 ~\mu $ mol/L, and the detection limit is $1.72 ~\mu $ mol/L (S/N = 3). And under the potential mode, the linear range of NIC is 10– $500 ~\mu $ mol/L, and the detection limit is $0.02 ~\mu $ mol/L (S/N = 3). In addition, the proposed sensor has been applied to in situ determination of NIC in tobacco leaves with acceptable relative derivation ranging from 5.04% to 7.63% between the sensor and high-performance liquid chromatography.