Application of temperature-sensitive hyperbranched polysiloxanes for the determination of polycyclic aromatic hydrocarbons in foodstuffs

In the present study, a novel temperature-sensitive hyperbranched polysiloxane dispersive liquid-liquid micro-extraction combined with high-performance liquid chromatography method (TS-HBPSi-DLLME-HPLC-UV) has been developed for the determination of five polycyclic aromatic hydrocarbons (PAHs) in instant noodles, in which temperature-sensitive hyperbranched polysiloxane (p(Ph-HBPSi-co-NIPAM)) was used as the extraction solvent. The method adsorbs the target analytes based on 7C-7C and hydrophobic interaction between p(Ph-HBPSi-co-NIPAM) and PAHs, and then separates the polymer with the adsorbed target analytes from the solution by a phase transition. Microextraction parameters of the method including polymer ratio, type and concentration of salt, pH, extraction time and volume of acetonitrile were examined in detail and optimized. At the optimum conditions, the established method showed good linearity (R2 >= 0.9971) with satisfactory limits of detection (0.089-0.16 ng mL-1) and limits of quantitation (0.27-0.48 ng mL-1). The values for intra-day and inter-day precisions were lower than 3.2% and 4.4%, respectively. Enrichment factors (EFs) and extraction recoveries (ERs) ranged from 62 to 70 and 75 to 85%, respectively. Finally, the proposed microextraction technique was validated by analyte addition and recovery studies, and applied to the determination of five PAHs in instant noodles, demonstrating that temperature-sensitive hyperbranched polymers have great potential for application in sample pretreatment techniques.