Splitting to Optimize Flow Rate

For the past several weeks, the lab has made progress in prepping for the summer and fall. For our kinetic method experiments, we were able to sort, clean, and inventory all samples for easy access including general inventory around the lab.  The pump for the flowing afterglow mass analyzer in the lab has finally been reinstalled (in it’s 800 pounds of glory), pump oil has been changed for all pumps, and gas tanks have been replaced for all of the instruments.  Now in week four, I have been able to start looking at the instrument my project uses and how to improve it so we can start running protein samples.

For my project, I am working with high performance liquid chromatography coupled with a tandem mass spectrometer.  The instrument is uses electrospray ionization for sample introduction and an ion trap mass analyzer.  Over the past several years, this instrument has been utilized in the study of the fragmentation of lysine and other proteomics projects.

To optimize the resolution of the chromatograph by introducing as small of an amount of solvent to the sample as possible, the flow rate of solvent must be lower than the HPLC can automatically achieve (on the 10 L scale).  I began working on a splitter between the two instruments.  This splitter had an approximately 1:80 ratio of solvent entering the MS versus waste.  The method, however, became somewhat unreliable when due to a packed high-pressure column there was not enough flow to push solution to the mass spectrometer.  Currently, I am working on fixing this problem by adjusting the tubing and columns to alter the backpressure and push solvent through at a low (but not too low) flow rate.  I hope to solve this issue soon so that I can begin analysis of the protein samples coming from the Forsyth lab!