Enhanced extraction of microplastics from terrestrial animal intestinal tissues via optimized fenton oxidation

Microplastics (MPs) are readily ingested by organisms and tend to accumulate in intestinal tissues, posing potential health risks. However, most existing MP extraction methods are designed for aquatic organisms and are unsuitable for terrestrial organisms with high lipid content. In this study, we developed an efficient Fenton oxidation-based method for extracting MPs from mouse intestinal tissues. Optimal conditions for iron precipitate removal were established at pH 0.8, with incubation at 50 °C for 2 h. Key digestion parameters (HO dosage, FeSO dosage, maximum reaction temperature, and secondary incubation time) were optimized using response surface analysis. The optimal conditions were: 37 mL of 18.5 % H₂O₂, 20 mL of 0.024 mol/L FeSO₄, a maximum reaction temperature of 60 °C, and a secondary incubation time of 35 h. Under these conditions, a digestion rate of 95 % was achieved, with minimal MP degradation. Specifically, mass loss was 2.5 %, size reduction was 2.78 %, the carbonyl index increased by 12.9 %, and infrared spectral similarity remained at 95 %. The method was also successfully applied to intestinal tissues from chickens, ducks, cows, and pigs, achieving digestion rates between 93 % and 95 %. These results demonstrate the method's effectiveness for extracting MPs from terrestrial organisms while minimal degradation, offering a valuable tool for MP research and health risk assessment.