2, 2′-azinobis-3-ethylbenzthiazoline-6-sulfonate (ABTS), 3, 3′, 5, 5′-tetramethylbenzidine (TMB), o-phenylenediamine (OPD) are typical chromogenic substrates to evaluate the activity of peroxidase-like nanozymes. However, these substrates are toxic, unstable, and the coloration reactions are slow. Herein, the classical starch-sodium iodide reagent was utilized as the chromogenic substrate to evaluate peroxidase-like activity of nanozymes. Starch-sodium iodine is less toxic, more stable and faster color reaction than ABTS, TMB and OPD. Under the catalysis of peroxidase-like nanozymes such as Mo₅N₆ nanosheets, graphene oxide nanosheets, Fe₃O₄ nanoparticles, CeO₂ nanoparticles, iodide ion (I^–) is oxidized by H₂O₂ to produce blue color complex (starch-I₂). Taking Mo₅N₆ nanosheets as the peroxidase-like nanozyme, the color reaction completed within 5 min at room temperature (25 ºC), and the chromogenic substrate remained stable within 30 days. The maximum reaction rate (V_max) using starch-sodium iodine as the chromogenic substrate was more than 100-fold higher than that of TMB. Based on this, a sensitive colorimetric sensor and facile portable agarose gel test kits were proposed and applied for the detection of H₂O₂ residue in liquid milk samples with fast response.

2, 2'-azinobis-3-ethylbenzthiazoline-6-sulfonate (ABTS)、3, 3', 5, 5'-tetramethylbenzidine (TMB)、邻苯二胺 (OPD) 是评估过氧化物酶活性的典型显色底物。像纳米酶。然而，这些底物有毒、不稳定，且显色反应缓慢。在此，经典的淀粉-碘化钠试剂被用作显色底物来评估纳米酶的类过氧化物酶活性。与 ABTS、TMB 和 OPD 相比，淀粉碘钠毒性更小，更稳定，颜色反应更快。在Mo ₅ N ₆纳米片、氧化石墨烯纳米片、Fe ₃ O ₄纳米颗粒、CeO ₂纳米颗粒、碘离子（^I-) 被 H ₂ O ₂氧化生成蓝色络合物（淀粉-I ₂）。以Mo ₅ N ₆纳米片为类过氧化物酶纳米酶，在室温（25℃）下，显色反应在5 min内完成，显色底物在30 d内保持稳定。以淀粉-碘化钠为显色底物的最大反应速率（V _max）比TMB高100倍以上。在此基础上，提出了一种灵敏的比色传感器和轻便的便携式琼脂糖凝胶检测试剂盒，并应用于液态奶样品中H ₂ O _{2残留的快速响应检测。}