Microelution Solid Phase Extraction(SPE) is essentially miniaturized SPE.  The technique is ideal for analysts that have small or limited sample volumes or for those that want to save time by skipping the dry down step, or for those that have very hydrophobic analytes that are either difficult to resolubilize after a dry down step, or ones that stick to polypropylene collection plates. Typical sample volumes are between 10–100 µL, and elution volumes can be as low as 25 µL and usually <150 µL, eliminating the need to perform a dry down step.

We often call our microelution SPE format “mini SPE” due the tiny frits and small sorbent bed mass, which allows the ability to elute with a small amount of organic solvent meaning that a dry down and reconstitution step is not required to achieve acceptable sensitivity. Referring to microelution as mini SPE also accurately helps to understand the benefits of this useful sample preparation technique—targeted extractions with ultra-high concentrations so let’s dive into the specifics of this unique SPE format.

Best Microelution Strategies

While using the Strata-X® microelution format, you still get the advantages of using our high-quality Strata-X polymeric sorbent that provides accurate extractions and good recoveries.  We ensure that our SPE sorbents undergo strict specifications to makes it a reliable SPE option.  The main difference in our normal 96-well plate format vs microelution 96-well plates is the dimension of the wells and the bed height.  In microelution we use elongated and thinner wells shapes to provide increased sorbent bed height for a large amount of surface area. Taller sorbent bed height means higher sorbent capacity, which means that a 2mg sorbent functions more like a 30mg sorbent. So, while only packing 2 mg in each well, we are still able to observe maximum analyte sorbent binding, which is evident in our high recoveries.

This enhanced well shape allows for small sample volumes and even smaller elution volume.  Typically, we recommend eluting with about 50 µL of solvent, which not only saves the cost of solvent, but also results in a more sensitive analyte extraction.  Using such a small extraction volume, no dry down or reconstitution is necessary, and this makes it ideal for thermally labile compounds that often need added sensitivity with no dry down in order to maintain the integrity of the analyte.   Below is an estimated time and cost savings that is associated with using the Strata-X Microelution SPE format.

what is microelution

Using a microelution format for small molecule or the extractions of peptides is not only a time savings, it’s also increasing the sensitivity of analytes through the analysis. Usually the sensitivity increases about 10-15x so not only does this create better chromatography but an easier job for you too!

Now with our new Strata-X Method Development and Peptide Screening Microelution 96-well plates, finding the correct phase for your analytes has never been so painless.  Strata-X Method Development offer the ability to use four different sorbents (Strata-X-A, -X-C, -X-AW, -X-CW) to find the correct phase for small molecule analysis.  For the Strata-X Peptide Screening Microelution plate, two different sorbents (-X-A,-X-CW) are in the plate for a full screen for diverse peptides to determine the accurate plate for your unique analytes.  Displayed in the data below, the ideal phase for different peptides was selected and the recovery and %RSD was recorded for verification of the selected phase.   Once a phase is selected, further method optimization may need to occur, but using a single method to screen for many different analytes with multiple phases provides a good general overview.

what is microelution

Less is more when it comes to Strata-X Microelution plates. You can get high recovery and sensitive extractions utilizing small volumes, further saving on time and money.  And now with two different method development plates, finding the right plate for your unique analytes has never been easier, ensuring accurate extractions, time savings, and no loss of thermolabile analytes.  To learn more about Strata-X microelution products, go to www.phenomenex.com/microelution or reach out to your Phenomenex sales representative to order your own Strata-X Method Development or Peptide Screening 96-Well Plate.

Questions regarding your method development and need a quick answer? Chat with our technical experts nearly 24/7 globally! 

Article Name
What is Microelution SPE and What are The Best Practices When Using It?
Microelution SPE is essentially miniaturized SPE.  The technique is ideal for analysts that have small or limited sample volumes.

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