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- Why it is strongly recommended to use a gradient method when analysing drugs in fed state biorelevant media
Why it is strongly recommended to use a gradient method when analysing drugs in fed state biorelevant media
Even when sample dilution is performed, a gradient is typically recommended to avoid significant changes that can occur in system properties after multiple sample injections.
If a gradient is omitted, a decrease in retention time can occur after multiple injections. A typical example is shown below from the 1st (left) to the 32nd (right) injection using just isocratic elution with a mobile phase containing 50:50 buffer: methanol WITHOUT introducing a gradient.
Introducing a step-gradient helps to elute components of biorelevant fed state media from the column along with a short re-equilibration readies the column before the next injection. A typical gradient including step-gradient that can be used is provided in the Figure and Table below.
