Determination of bongkrekic acid and isobongkrekic acid in rice noodles by HPLC-Orbitrap HRMS technology using magnetic halloysite nanotubes

•A magnetic halloysite nanotubes (Fe3O4/HNTs) was used as a MSPE sorbent.•A new HPLC-Orbitrap HRMS method was developed for robust analysis of BKA and IBKA.•The Box-Behnken design (BBD) was employed to optimize the adsorption parameters.•Method is easy to implement enabling BKA and IBKA analysis in rice noodles. The existing extraction and detection methods of bongkrekic acid (BKA) and isobongkrekic acid (IBKA) are complex, time-consuming and solvent-consuming. In this work, a simple and fast pre-concentration procedure based on Fe3O4/HNTs was developed for the determination of BKA and IBKA in rice noodles using HPLC-Orbitrap HRMS. The structure and morphology of Fe3O4/HNTs was characterized by means of XRD, SEM, FT-IR and VSM. Parameters affecting the extraction efficiency including adsorbent amount, pH, extraction time, type and volume of eluent were investigated by employing the response surface method. Results indicated that the proposed method had favorable linearity in the concentration range of 2–200 μg/L with a correlation coefficient >0.998. Method LOD and LOQ were 0.3 μg/kg and 1.0 μg/kg, respectively. Finally, the method was successfully applied to determine BKA and IBKA in rice noodle samples from southern China with recoveries ranging from 79.8% to 102.6% and relative standard deviation (RSD) of 4.2%-7.1%.