This device is the first to make automated connections with user-packed capillary traps, columns, and capillary emitters. The source uses plastic rectangular inserts (referred to here as cartridges) where individual components (i.e., trap, column, or emitter) can be exchanged independent of one another in a plug and play manner. Automated robotic connections are made between the three cartridges using linear translation powered by stepper motors to axially compress each cartridge applying a well controlled constant compression force to each commercial LC fitting. The user has the versatility to tailor the separation (e.g., the length of the column, type of stationary phase, mode of separation) to the experimental design of interest in a cost-effective manner. The source is described in detail and several experiments are performed to evaluate the robustness of both the system and the exchange of the individual trap and emitter cartridges. The standard deviation in the retention time of 4 targeted peptides from a standard digest interlaced with a soluble Caenorhabditis elegans lysate ranged between 3.1-5.3 seconds over 3 days of analyses. Exchange of the emitter cartridge was found to have an insignificant effect on the abundance of various peptides. In addition, the trap cartridge can be replaced with minimal effects on retention time (<20 s).
The article is published online in the journal Molecular & Cellular Proteomics and is free to access.