A biocompatible O‐carboxymethyl chitosan/acrylic acid copolymer over magnetic graphene oxide used for determination of catechins in urine prior to ion monitoring‐gas chromatography/mass spectrometry

Catechins, as powerful flavonoids with antioxidant properties, are crucial for the preservation of the human body against free radicals and for promoting overall health. Research has shown that the presence of catechins in urine is linked to a reduced risk of gastric and esophageal cancer. This study introduces an innovative approach using a novel nano‐composite material, composed of magnetic graphene oxide coated with a biocompatible O‐carboxymethyl chitosan/acrylic acid copolymer, for extracting catechins from human urine. The extracted catechins were then analyzed using gas chromatography/mass spectrometry‐selected ion monitoring analysis. Under the optimum conditions, the analytical figures of merit for catechin and epicatechin were linear dynamic range: 0.5–1000 ng/mL, R2 of 0.9991; limit of detection equal to 0.1 ng/mL; relative standard deviation: 4.1 and 3.1 (C = 50 ng/mL, n = 3); and relative recovery was 94%, respectively. The application of this method holds significant promise for advancing clinical and toxicological studies, as well as establishing potential associations between tea consumption and disease prevention.