Capillary Chromatography - History of Capillary Columns 5


They employed a similar device as that invented by Desty but the drawing roller was extended below the drawing oven to allow the insertion of two coating nozzles and two drying ovens. The polymer they employed was Pyralin PI-2550 (Dupont) and was used neat or as a solution n N-methyl-2-pyrrolidone. Previous experience with the rigid columns of Desty provided suitable deactivating and coating techniques and the low activity of the surface is confirmed by the chromatograms shown in figure 4.


The typical base/acid pair, 2,4-dimethylaniline and 2,6-dimethylphenol were used to evaluate the surface polarity and n-heptadecane and n-octadecane was included for comparison. It is seen that even at high sensitivity neither polar component is lost due to adsorption on the glass surface. The soft glass alternative to fused quartz was, however, never exploited commercially despite it being much easier and less expensive to make probably because the fused silica was viewed as 'state of the art' material.



Figure 4, Chromatogram Demonstrating the Low Surface Activity of Flexible Soft Glass Capillaries