Mobile phase preparation automated mixing

Mixing errors automated mobile phase preparation. Problems encountered with an automated system can still be the result of analyst error. For example, the wrong component may have been dispensed into the HPLC solvent reservoir. Where there is an apparent issue in relation to the retention time of a compound, the mobile phase should always be checked for accuracy of preparation. Proportioning valve errors can also cause a problem with automated systems. When the valve ceases to dispense the correct amount of either solvent, the retention time of the compounds of interest will vary. 

Another feature of modern HPLC systems that makes them desirable for both analytical and preparative applications is the complex mobile-phase gradients that they are capable of producing. Many systems come equipped with a pump integrator or controller (computer) that allow a number of different mobile-phase solvents to be simultaneously mixed and delivered to the stationary phase. Since this process is automated, complex gradients used for a particular application are quite reproducible. 

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