Do Flow Rates Matter in SPE?

Have you ever wondered why solution flow rates are so important when performing sample preparation with solid phase extraction (SPE)?  If you have, read on – I have the answer for you!

Throughout my college career, the phrase “like dissolves like” was referred to quite frequently.  This phrase was particularly relevant when we did solubility experiments and for good reason – it’s 100% true!  Solvents tend to dissolve solutes with physical and chemical properties that are similar to theirs.  Other factors such as temperature, pressure and pH can affect the solubility of solutes as well, but let’s just keep it simple for the purposes of this discussion and keep it focused on physical and chemical properties.  Given this simplistic definition of solubility, the opposite stands true as well – solutes don’t tend to dissolve into solvents with differing physical and chemical properties.  These solvents and solutes want to stay as far from each other as is possible.

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