NanoESI MS can be coupled to high performance liquid chromatography (HPLC) using a variety of sizes of liquid chromatographs. We have maximized the sensitivity of the QSTART XL by performing chromatographic separations on a UltimateT nano-HPLC, from Dionex/LC Packings. A relatively large volume of sample (1-25 l) can then be loaded onto an appropriate reverse-phase column (e.g., C8, C18) that can be separated into its various component parts by eluting with a gradient at 100-2000 nl/min. This reduces sample preparation time and loss during analysis. Examples whereby this could enhance the information gathered includes an enzymatic digest of protein that can be analyzed by LC/MS for peptide mapping/sequencing. LC/MS can be used for the quantitative analysis of trace samples including metabolites or contaminants. LC/MS/MS is almost the best method available to study pharmacokinetics, the fate of drugs, pesticides and insecticides. Not only can it quantitate the amount of specimen in a mixture but also elucidate the structures of the specimen. Furthermore, 2D chromatographic methodology utilizing the multiple micro-valves integrated into the UlimateT have improved proteomic analysis of complex mixtures. Information-dependent acquisition (IDAT) allows for on-the-fly MS/MS based on switching criteria as desired greatly increasing the amount and types of data obtained including specific peptide information in a mixture or targeted modifications.