Development of a colloidal gold immunochromatographic strip for rapid and sensitive detection of nicotine

Nicotine (NCT) is commonly contained in e-cigarette oils, and long-term nicotine intake can exacerbate car-diovascular disease, neurodegenerative disease, and lung cancer. Therefore, there is a need to develop a fast and sensitive method for detecting NCT in e-cigarette oils. We prepared anti-NCT monoclonal antibodies (mAbs), which belong to the IgG2 subclass. The optimum mAb had a half-maximal inhibitory concentration (IC50) of 6.81 ng/mL for NCT. We developed a colloidal gold immunochromatographic strip (CG-ICS) to detect NCT content with a visual cut-off and limit of detection of 20 ng/mL and 0.40 ng/mL, respectively. The recovery rates of NCT from spiked samples ranged between 100.36% and 109.96% based on CG-ICS. These results were consistent with those obtained from high performance liquid chromatography (HPLC). We confirmed the reliability of CG-ICS using NCT-positive samples. Therefore, CG-ICS represents an effective and rapid on-site screening tool for the detection of NCT in e-cigarette oils.