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Oasis 2x4 SPE Method Development
This example method provides a freely adjustable framework for measuring the adaptability of the OneLab environment to workflows from different application fields. It helps to understand various nuances of the code-free, universal protocol designer and provides general indications as to the feasibility of a project. Scripts generally require fine adjustment to correct for variables and support specific labware implementation.
┛This method showcases an SPE-based Sample Prep┏
Automated Mixed-Mode SPE Method Development Using Andrew+
Quantitative and qualitative LC-MS analysis of complex biological samples requires extensive sample clean-up procedures to remove undesirable matrix components that may otherwise coelute and adversely affect the quantitation of the target analyte. Mixed-mode (reverse phase-ion exchange) solid-phase extraction (SPE) is an effective and well-proven technique for sample cleanup. However, developing mixed-mode SPE methods for the quantitation of analytes can be a tedious process. A good understanding of the physical and chemical properties of the analyte and the SPE sorbent chemistries is essential to selecting a suitable mixed-mode SPE sorbent that will not only remove the undesired components from the sample matrix but also result in good analyte recovery from the sample matrix. Furthermore, mixed-mode SPE method development involves several steps requiring precise and accurate pipetting of samples, reagents, and solvents.
Waters Oasis Method Development or sorbent selection plate simplifies this sorbent selection process, wherein it includes all four different mixed-mode ion exchange/reverse phase sorbent chemistries (MCX, MAX, WAX, and WCX) in a single plate format and utilizes just two optimized and proven protocols (2x4 sorbent selection method) to develop a mixed-mode SPE method (Figure 1). While the Oasis Method Development or sorbent selection plate with the 2x4 protocol simplifies the sorbent selection process, automation of this Oasis 2x4 sorbent selection protocol using the Andrew+ pipetting robot makes the entire SPE sorbent selection process rapid, reproducible, accurate, and robust.
◼️ PROTOCOL | Oasis 2x4 SPE Method Development – Andrew+
In this protocol, the automation of the Oasis 2x4 sorbent selection method using the Oasis Method Development 96-well μElution Plate is demonstrated by extracting four analytes Imipramine, 1-decanesulfonic acid, Ketoprofen, and Valethamate from spiked human blood plasma samples. Each of these analytes produces good analyte recovery, specific to the four Oasis mixed-mode sorbent chemistries MCX, WAX, MAX, and WCX respectively. All the steps in the SPE sorbent selection method development from loading, washing, and elution as well as controlling the vacuum of the SPE manifold are automated by the Andrew+ platform, except for changing the SPE sample collection plate in the vacuum manifold between washing and elution steps of the protocol. However, vacuum control or programming of the vacuum pump is available only when the IKA VACSTAR control vacuum pump is used. The SPE extracted samples are then quantified by LC-MS.
Figure 1: Overview of the conditions used in the Oasis 2x4 SPE Method Development.
- Microplate Vacuum+ | p/n 176004579
- IKA VACSTAR control vacuum pump | p/n 0020109375 for EU/CH, 0020109376 for the US, 0020109377 for the UK
- ACQUITY UPLC I-Class system
- Xevo TQ-S Tandem Quadrupole Mass Spectrometer
- Oasis method development 96-well μElution plate, 2 mg sorbent/well | p/n 186004475
- Waters QuanRecovery™ 700 μL 96-well plate | p/n 186009185
- Axygen 12-well reservoir, 12 channel trough | p/n RES-MW12-HP
- Falcon 50 mL conical centrifuge tube | p/n 352070
- Waters silicone/PTFE cap mat for 96-well plate, 7 mm round wells | p/n 186006333
- ACQUITY UPLC BEH C18 column, 130Å, 1.7 µm, 2.1x50 mm | p/n 176000863
Check out the Application Brief "Andrew+ Automated Mixed-Mode SPE Sorbent Selection Method Development for LC-MS Analysis" (Waters, p/n 720007302EN)
Get more insights into the Oasis 2x4 Method in the Application Note "Oasis 2x4 Method: Proof of Concept" (Waters, p/n WA60090)
Check out the user manual for step-by-step instructions on how to install the IKA VACSTAR control vacuum pump with the Microplate Vacuum+ device