MODcol® Multipacker® Technical PosterSource: Grace
By Reno Nguyen, Jochen Saar and Theresa Riley
One of the challenges in scaling up chromatography processes from analytical method development to pilot or production scale is optimizing the column packing procedure. Early method development work is typically done on pre-packed columns supplied from HPLC stationary phase manufacturers. However, for performance, economic, availability, and simple logistics issues most users migrate to dynamic axial compression (DAC) columns that are packed in-house once processes require large i.d. columns, >100mm i.d. Chromatographers experience numerous difficulties packing stable beds in process/production columns. These problems include non-uniform compression, bed deformation, channeling, void formation and crushing under improper packing. The use of true dynamic axial compression can overcome these issues and produce high quality beds that will exhibit high performance over a broad range of flow rates as evidenced by HETP (height per each theoretical plate) test. Placing constant pressure on a moveable piston gives it the dynamic capability of maintaining a consistent homogeneous bed. The resulting elimination of voids and channeling provides ultimate chromatographic performance. While stationary phase manufacturers may give guidance on packing procedures for their phases, end users often must engage in a trial and error process to determine how best to pack an HPLC phase using their individual DAC system, often sacrificing valuable product in the process. Here we outline a method for optimizing DAC packing using the MODcol® MultiPacker® columns for various HPLC phases including polymer resins, 300Å silica phases, 120Å silica phases, and irregular 60Å and 500Å silica. The availability of smaller i.d. DAC columns with the MODcol® system helps allow users to lock-in scaleable packing processes early in development to further minimize risk involved in scale-up. The Spring® column's main feature is the presence of a set of Belleville washers which provides constant pressure on the resin bed. Examples are given for DAC columns ranging from 25mm i.d. to 101mm i.d.