The HCT LC-MSn is a high capacity ion trap (HCT) mass spectrometer that offers dramatically improved performance for proteomics, metabolite profiling and other demanding LC-MSn applications. The instrument features fast acquisition of MS and MS/MS data across the narrowest HPLC peaks in real-time. Typical sensitivity is at the low attomole/femtogram level. The instrument provides excellent quality mass spectra and operates with a wide dynamic range for identification of low abundance compounds in biological samples.