A rapid clean-up method for the quantitation of 5-hydroxymethyl-2-furaldehyde in thermally treated abalone (Haliotis discus) muscle by HPLC-MS/MS

Currently, no rapid pretreatment method for 5-hydroxymethyl-2-furaldehyde (HMF) determination in solid samples (e.g., seafood products) is available. Herein, we address this gap and develop a quick, easy, and effective pretreatment method for HMF quantitation in thermally treated abalone using dispersive solid-phase extraction (DSPE) combined with dispersive liquid–liquid microextraction (DLLME). In particular, 200 mg of octadecylsilane, 100 mg of primary secondary amine, and 10 mg of graphitized carbon black were employed under optimized DSPE conditions, while optimized DLLME conditions corresponded to a dispersing solvent/extraction solvent volume ratio of 4 : 1, water/(dispersing solvent + extraction solvent) volume ratio of 1 : 1, and an extraction time of 5 min. After DSPE–DLLME pretreatment, HMF determination was performed by high-performance liquid chromatography coupled with triple-quadrupole mass spectrometry (HPLC-MS/MS) using a reversed-phase C18 column (50 mm × 2.5 mm, 2 μm). The isotope dilution technique employed for HMF quantification efficiently inhibited the matrix effect and accounted for the operation error of the DSPE–DLLME method. The developed method exhibited a low limit of quantification (0.3 μg L−1) and excellent linearity (R2 = 0.999) and was therefore used to evaluate the HMF content of thermally treated abalone products. The recoveries of HMF ranged from 86.5 to 110.9% in steamed abalone and from 90.1 to 102.7% in baked abalone, and the HMF content of baked abalone (1.9–15.6 μg kg−1) exceeded that of steamed abalone (0.7–1.8 μg kg−1). Compared to traditional solid-phase extraction, the developed DSPE–DLLME approach allowed the rapid and simple determination of HMF by HPLC-ESI-MS/MS with low solvent consumption.