Mobile phase strength, effect development

Parameters that should be tested in HPLC method development are flow rate, column temperature, batch and supplier of the column, injection volume, mobile phase composition and buffer pH, and detection wavelength [2], For GC/GLC methods, one should investigate the effects of column temperature, mobile phase flow rate, and column lots or suppliers [38], For capillary electrophoresis, changes in temperature, buffer pH, ionic strength, buffer concentrations, detector wavelength, rinse times, and capillaries lots and supplier should be studied [35, 36], Typical variation such as extraction time, and stability of the analytical solution should be also evaluated [37],... 

The major contrast with GC is that the mobile phase eluent strength (affecting k ) and the relative selectivity between analytes (a) can both be readUy varied. In GC the carrier gas composition has practically no effect on selectivity, and varying temperature affects only k. The large number and range of parameters to be evaluated to optimize the eluent composition makes HPLC method development more complex. Every benefit comes with its own price ... 

Following completion of the initial experiment, the focus shifts to the separation of the test mixture or organic compounds using the HPLC instrument. The effect of solvent strength on k and the effect of mobile-phase flow rate on will be considered by retrieving previously developed Turbochrom methods and making manual injections. 

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