Sample Prep, SPE

Nigel Tooke

How to achieve faster sample prep, cleaner extracts, and instant sensitivity gains

October 15, 2020 at 9:06 AM / by Nigel Tooke

A prime objective of bioanalytical sample preparation is to achieve high analyte recovery in low elution volumes, with rapid delivery of clean extracts that support robust high sensitivity analysis to meet goals for detection limits. What's best between conventional solid phase extraction (SPE) and microelution SPE?

While conventional solid phase extraction (SPE) combined with evaporation may make this possible, microelution SPE is a much more effective approach that delivers the purity of SPE plus the concentration achieved by evaporation but without the downsides.

Instant sensitivity gains with small elution volumes

Sensitivity is all about achieving a high concentration of the analyte in a low background of interfering substances from the matrix. To do this, Biotage® Mikro SPE plates have been designed with taller, narrower SPE beds to enable high capacity sample loading, and extremely low dead volumes for very small elution volumes. This approach increases sensitivity at least 10x compared to conventional SPE sample prep, because you can load higher amounts of sample, and use very small elution volumes.

new SPE microelution workflow

To get the same sensitivity gain using evaporation, you would spend another 30–60 minutes per plate, and also risk losing analytes that stick to surfaces, are highly volatile, or are degraded at high temperatures.

Cleaner extracts means less instrument downtime and more robust analysis

Analyte sensitivity isn’t just about the concentration of the extract. Biological fluids are complex matrices and contain many components that can interfere with the analysis, reducing the signal in the LC-MS/MS instrument. These matrix effects can lower sensitivity (suppression of the signal), and dirty extracts can contaminate your LC column or the MS source, which means having to power down and clean the source, or replace the column frequently. Increasing the purity of samples in your lab by implementing microleution sample prep will avoid these problems and increase lab efficiency.

Biotage Mikro SPE containing EVOLUTE sorbents come in a range of media types. All have optimized features that eliminate proteins (a major cause of contamination), giving you cleaner extracts and more reliable analysis. Mixed-mode EVOLUTE sorbents also enable you to wash away matrix components such as phospholipids without losing analyte, leading to less ion suppression and improved signal to noise ratios, which makes your quantitation more reliable.

Streamlining the sample preparation process

As well as cutting out the evaporation step, you can reduce your sample prep time even more with Biotage Mikro plates packed with EVOLUTE sorbents. Using most sorbents, the SPE process requires conditioning and equilibration steps before you load the sample. EVOLUTE sorbents are water wettable, meaning that these two steps can be eliminated. We call it the Load-Wash-Elute process.

Find out more about how microelution SPE can make your sample prep more efficient and boost the sensitivity of analysis in your lab.

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Topics: Sample preparation, Solid-phase extraction, detection limit, Microelution

Nigel Tooke

Written by Nigel Tooke