Long Term Test on a New Four-Channel HPLC Pengxiang Yang 1, BC Cha , Terry Olney 1, John Brann 2, Christopher Elicone 2 1 Thermo Fisher Scienti c, 355 Oaks River Parkway, San Jose, CA, USA, 95134 2 Thermo Fisher Scienti c, 101 Constitution Blvd., Suite E, Franklin, MA, USA 02038