Hemoglobin, particularly glycated hemoglobin, serves as the gold standard for diagnosing diabetes in clinical settings. In this study, a triazolinone derivative, 3-chloromethyl-1,2,4-triazol-5-one (CMTO), was conjugated to polyethylenimide-modified magnetic nanoparticles via an amination reaction, resulting in the formation of a novel composite material, CMTO@Fe