Proteome analysis is a popular method to discover biomarkers for the prevention and diagnosis of diseases. Since saliva is a non-invasively available body fluid, gathering of saliva causes minimal harm to patients. Therefore, detection of proteins for the prevention and diagnosis from the saliva sample may be the preferred method, especially for children and elderly people. However, the abundance of salivary proteins and contaminant proteins from food and mouth bacteria obscure identification of proteins present in the saliva at low concentrations. To address this problem, we developed a shotgun proteomic method using two-dimensional nano-flow LC tandem mass spectrometry. We report here that our method is able to detect proteins quantitatively even in small sample volumes of saliva
