Abstract
An alternative method for determining the extra‐coil volume (V ext) of a J‐type centrifuge and its ancillary equipment is given based upon displaced volumes of stationary phase. The extra‐coil volume (V ext) is determined by plotting the volume of stationary phase displaced from the coil and extra‐coil volume combined (V E ), against the square root of the mobile phase flow rate. The extra‐coil volume is the intercept on the V E axis for a zero flow rate of mobile phase. This extra‐coil volume is then used to produce a stationary phase retention characteristic where the intercept on the retention axis is 100% for a zero flow rate of mobile phase. Experimental evidence was gained for a heptane–ethyl acetate–methanol–water (1.4:0.1:0.5:1) v/v phase system, in normal phase mode using three helical stainless steel coils. The internal diameters of these coils were 3.73 mm, 5.33 mm, and 7.73 mm. Retention studies were conducted at rotational speeds between 600 and 1200 rpm. The same phase system was also tested in a multi‐layer PTFE coil in reverse phase mode at a rotational speed of 800 rpm. The internal diameter of the tubing for the PTFE coil was 1.6 mm. All of the coils used were fitted to a J‐type centrifuge with a rotor radius of 110 mm. These retention studies allowed the extra‐coil volume to be tested under conditions of different rotational speeds and coil tubing internal diameters. It was also tested using different tubing material, and in both normal and reverse phase modes.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call