When phosphate-buffered saline (PBS) was used instead of acetonitrile, the binding constant was substantially small (9.0 × 10 2 M -1 ) for the poly1/OTA pair at 273 K (Fig. ). This sharp contrast (acetonitrile versus PBS) enabled selective capturing/release for efficient separation of OTA from food matrices with 95% of recovery (Fig. ). In addition, iterative capture and release of OTA was achieved using poly1 with excellent durability (Fig. ). This is in contrast to the use of a commercially available immunoaffinity column showing poor extraction of OTA from the corresponding coffee bean matrix (Fig. ) and a gradual decrease in capturing/releasing efficiency (Fig. ), validating the advantage of using peptides rather than proteins. Thus, the use of acetonitrile improved the solubility of organic molecules and thereby suppressed non-specific binding to unfunctionalized units of polymers, and this led to efficient and repeatable separation of OTA from food matrices.