Magnetic dummy template molecularly imprinted particles functionalized with dendritic nanoclusters for selective enrichment and determination of 4-methylnitrosamino-1-(3-pyridyl)-1-butanone (NNK) in tobacco products

The compound 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), one of the tobacco specific nitrosamines (TSNAs), is widely recognized as a major carcinogen found in tobacco products, environmental tobacco smoke and wastewater. Thus, a selective enrichment and sensitive detection method for monitoring the risk of NNK exposure is highly desirable. In this study, a magnetic molecularly imprinted polymer (MMIP) functionalized with dendritic nanoclusters was synthesized to selectively recognize NNK via the dummy template imprinting strategy, aiming to avoid residual template leakage and increase the imprinting efficiency. The nanocomposites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, as well as vibrating sample magnetometry (VSM) and nitrogen adsorption/desorption analysis. The resulting MMIPs exhibited high adsorption capacity, fast binding kinetics and good selectivity for trace amounts of NNK. A rapid, low cost and efficient method for detecting NNK in tobacco products was established using magnetic dispersive solid-phase extraction coupled with HPLC-DAD with a good linear range of 0.1–250 μg mL(−1). The limit of detection (LOD) and limit of quantification (LOQ) of NNK were 13.5 and 25.0 ng mL(−1), respectively. The average recoveries were 87.8–97.3% with RSDs lower than 3%. The results confirmed that the MMIPs could be used as an excellent selective adsorbent for NNK, with potential applications in the pretreatment of tobacco products.