Immunoglobulin, also known as antibodies, is an important component of the immune response. It has been found that humans and mammals contain five different antibodies, namely IgA, IgD, IgE, IgG, and IgM. Based on subtle differences in amino acid sequences, these antibodies can be classified into different subtypes, for example, IgG can be classified into IgG1, IgG2, IgG3, and IgG4 subtypes. Immunoglobulin binding proteins are a class of ligands used in biological affinity chromatography, with Protein A and Protein G being the two main types. Both of these proteins specifically bind to the Fc segment of immunoglobulin, making them suitable for purification of immunoglobulin. There are differences between Protein A and Protein G in the types of antibodies they bind to and the strength of their binding affinity. Taking human immunoglobulin as an example, Protein A chromatography column has high affinity for IgG1, IgG2, and IgG4, but no affinity for IgG3. At the same time, it has a certain affinity for the other four immunoglobulins; Protein G has high affinity for all four IgG subtypes, but lacks affinity for IgA, IgD, IgE, and IgM [1].

Bio Monolith chromatography column packing is a polymer matrix that can maintain stability in a wide range of pH 2-11; And due to the fact that the chromatographic column is a monolithic column with a small column bed, it is advantageous for rapid conversion between different mobile phases, thereby providing higher analysis speed and flux. Based on the specificity of the chromatographic column and the characteristics of the sample, this study analyzed the IgG content in health food using an Agilent Bio-Mnolith Protein G chromatographic column, and measured IgG from different sources to verify the applicability of the Bio-Mnolith Protein G chromatographic column.