Waters Assoc packed columns

A major requirement for column tubes in HPLC is constancy of the column diameter when changing the pressure drop along them. If this is not so, the stability of the packing is affected on changing the pressure drop, which destroys the column efficiency. All available polymeric tubes, such as PTFE, nylon or plastic tubes, show a definite pressure dependence of the tube diameter. Apart from this, polymeric materials, except PTFE, are easily attacked by organic solvents. For these reasons polymeric materials are unsuitable as column tube materials in HPLC. Recently, however, the application of a radial compressed PTFE column for preparative LC was reported (Waters Assoc.). 

Two manufacturers have produced such chromatographs. In 1975, Waters Assoc, introduced the Prep-LC 500. The important advantage in the design of this instrument is the use of a disposable, pre-packed column with a plastic wall. This cartridge is filled in a cylindrical compression chamber and will be rapidly compressed prior to sample injection. This procedure compresses the column packing into a highly efficient chromatographic bed. 

Houston Inst.) were used. A prepacked reversed column (30x0.4 cm I.D.) containing an octadecyl chemically bonded (Waters Assoc.) was utilized. A precolumn (5x0. cm) also packed with C g material was used to protect the main column. Main column was washed daily with double distilled water, followed by methanol water (30 70), and preserved in the later in between use as previously described (1). 

Stainless steel, 4 mm X 30 cm. A short column (4 mm X 2 cm) packed with Bondapak C 3/Corisal B (Waters Assoc.) used to guard the main column Mobile phase... 

---