Human blood, as an important fluid sample in metabolomics, is mainly divided into plasma and serum. Compared to plasma, serum does not contain fibrinogen, and its components are relatively simple with over 1000 kinds of endogenous small molecule metabolites, making it an important metabolomics fluid sample. Due to the variety and extensive range of polarities of small molecule metabolites in serum, including highly polar substances such as amino acids, glucose, and nucleosides, as well as low-polarity......