Shotgun proteomics, also known as shotgun method, refers to the utilization of bottom-up proteomics techniques to study all proteins present in complex mixtures such as serum, urine, and cell lysates. It combines high-performance liquid chromatography (HPLC) and mass spectrometry (MS). The uniqueness of shotgun proteomics lies in its ability to identify and quantify multiple proteins while minimally separating them.