Covalent organic frameworks blended cellulose nanocrystal for in-needle syringe solid phase extraction of polycyclic aromatic hydrocarbons in dark roasted coffee

Abstract

A novel solid phase of an in-needle syringe solid-phase extraction system (InNS-SPE), covalent organic framework blended cellulose nanocrystal nanocomposite (COF@CNC), was prepared for the adsorption of polycyclic aromatic hydrocarbons (PAHs) in dark roasted coffee samples. Trace PAHs in dark roasted coffee were effectively extracted through π-π stacking interaction with COF@CNC. The effect of various experimental parameters on the extraction performances, including adsorbent dosage, desorption solvent and its volume, sample volume, elution flow rate, and ionic strength, were studied. The extraction efficiency, quantified as extraction recovery, was evaluated using high performance liquid chromatography equipped with fluorescence detection (HPLC-FD). Under the optimal conditions, the COF@CNC sorbent-based InNS-SPE with HPLC-FD can be used for detecting four PAHs, including acenaphthene, fluoranthene, phenanthrene, and pyrene, in the linear range of 5 to 1,000 ng mL−1, with a good correlation coefficient (R2 > 0.9968). The detection limits were found in the range of 3.07–5.49 ng mL−1. The COF@CNC sorbent exhibited good reusability (12 times, with a slight change in % recoveries). Furthermore, the proposed InNS-SPE based COF@CNC method was environmentally friendly due to the use of a small volume of desorption solvent (1.0 mL). The extraction of PAHs from dark roasted coffee using the developed tool was achieved with recoveries in the range of 82.50–105.76. It proved that the method was unaffected by the sample matrix. Therefore, the COF@CNC nanocomposite sorbent-based InNS-SPE is an effective tool for detecting PAHs in dark roasted coffee samples.