Liquid-phase microextraction combined with gas chromatography mass spectrometry for rapid determination of nicotine in one-drop of nightshades vegetables and commercial food products

A simple, rapid and sensitive ultrasound-assisted hollow fibre liquid-phase microextraction (UA-HF-LPME) is evaluated for the determination of nicotine in one-drop of nightshade vegetables and some of the commercial food products. The optimum extraction of nicotine was obtained by using 1.5 μL as an extracting solvent in 1.0 cm of hollow fibre for 10 min extraction time with addition of salt. The calculated calibration curves showed a high level of linearity in the range 2–100 ng g−1 with correlation coefficients >0.998. The limit of detection (LOD) for the target analyte was found to be in the range of 0.2–0.5 ng g−1 and the relative standard deviations (RSD) of 2.3–4.5% were obtained. The results showed that under the optimised experimental conditions, the method showed good sensitivity and relative recoveries, as well as advantages such as linearity, simplicity, low cost and high feasibility. The extraction performance of present method to the target compound was also compared with drop-to-drop solvent microextraction (DDSME) and we found that the present approach showed better extraction efficiency of target molecule from sample solution. Finally, the proposed method was successfully applied for the determination of nicotine in nightshade vegetables (potatoes, tomatoes, peppers and eggplants) and commercial food products (tomato sauce, tomato juice, and pepper sauce).