The optional Column Switching Valve (EcoSEC Elite^®) allows the user to reduce column switching time and easily switch between low MM and high MM range columns on the EcoSEC Elite GPC System with RI Detector and the EcoSEC Elite GPC System with RI and UV Detectors.  This option can help to eliminate temperature related baseline drift that is normally seen following a column change.  By installing an optional column switching valve and replacing the reference column with another analytical column, an analysis can be performed on column 1 while equilibrating column 2. After switching the valve, column 2 becomes the analytical column while column 1 will be in the flow path to the reference side of the RI detector flow cell. Since the column switching valve changes column sets while the oven door remains closed and switches to an already equilibrated column set, a stable baseline is rapidly established.