Whats the difference between Isocratic chromatography and Gradient chromatography?
The simplest approach to liquid chromatography is to maintain a constant mobile phase composition during the course of the chromatogram. Because the phrase “constant mobile phase composition” is awkward to use repeatedly, the term isocratic was invented by Csaba Horvath in 1970 as an alternative. Unfortunately, this approach (isocratic LC) sometimes gives rise to a situation where some sample components wash through the system too quickly for useful analysis while others move too slowly. In short, no single mobile phase composition provides reasonable retention for all the components int he sample. If the mobile phase is made weaker in order to slow down the fast-moving components, the slow-moving components take even more time. If the mobile phase is made stronger in order to speed up the slow-moving components, then the fast moving components elute even earlier. The problem can be solved by changing the mobile phase composition during the run, starting with a relatively weak mobile p
