Retention time mixing errors

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. 

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