Since capillary liquid chromatography coupled with tandem mass spectrometry plays an essential role in proteome analysis by means of shotgun proteomics, recent advances in high-efficiency multidimensional separation and the availability of modem mass spectrometers with high sensitivity and high accuracy have led to new biological applications.Nevertheless, digested peptides for shotgun proteomics exhibit extremely high complexity with a wide dynamic range of concentration, and it is still a challenging task to analyze the entire proteome of cells of interest.Recently, by using one-dimensional nanoLC-MSMS with a 350 cm long, 100 micron i.d., monolithic silica-C18 capillary column, we successfully identified the proteome expressed in E.coli cells on a microarray scale [1].Four microgram of E.coli tryptic digest was injected onto the column, and a 41 h gradient was applied with a flow rate of 500 nL/min at less than 20 MPa.In total, 22,196 non-redundant tryptic peptides from 2,602 proteins, including 830 membrane proteins, were identified from the E.