Bubble-oscillation-driven solid-phase microextraction with interface synergistic adsorption for ultrasensitive detection of capsaicinoids

Conventional solid-phase microextraction (SPME) techniques often rely on mechanical stirring devices to improve interfacial mass transfer and enhance detection sensitivity. In this study, we developed a highly sensitive bubble-driven solid-phase microextraction (BD-SPME) method that eliminates the need for mechanical stirring. This was achieved by constructing a bubble-oscillation-enhanced mass-transfer system based on a MnO 2 -loaded HLB Wax interface with high adsorption efficiency (HLB Wax @MnO 2 ). Adsorption kinetics showed that BD-SPME achieved an adsorption capacity of 1.27 μg/mg within 20 min, 1.78 times greater than that of the conventional SPME method. Isothermal adsorption curves confirmed a multilayer adsorption of capsaicin (CAP) and dihydrocapsaicin (DHC) on HLB Wax @MnO 2 . Furthermore, BD-SPME demonstrated stable performance across six types of chili peppers, with recovery rates ranging from 90.48% to 119.65% and relative standard deviations between 1.37% and 16.79%. Overall, BD-SPME overcomes the limitations of traditional stirring devices and offers a sensitive, stable, and straightforward sample pretreatment technique.