Ion Chromatography - The Ion Chromatograph
Late in the 1930s and early 1940s Martin and Synge introduced a different form of chromatography, liquid-liquid chromatography, by supporting the stationary phase, (water), on silica gel as a packed bed and employed it to separate some acetyl amino acids. Their work was published in 1941 and in their paper suggested that the replacement of the liquid solvent with a suitable gas, which would improve solute transfer between the two phases, which, in turn, would result in better separations. Thus, the concept of gas chromatography was evoked.. From then on progress in chromatography development was very rapid In the same publications, Martin and Synge recommended the use of small particles and high pressures to improve the separation which subsequently was shown to be the critical factors that produced high performance liquid chromatography. To quote Martin's original paper,
"Thus, the smallest H.E.T.P. (the highest efficiency) should be obtainable by using very small particles and a high pressure difference across the column".
The recommendation of Martin in 1941 provides the essential conditions necessary to obtain the high efficiencies and high resolution now achieved by modern LC columns.
Figure 27. A Modern Ion Chromatograph by Metohm