Oasis Cartridges and 96-Well Plates

Significance of the Topic

This manual outlines a versatile family of solid‐phase extraction (SPE) sorbents and devices designed to streamline sample preparation across environmental, food, clinical, and pharmaceutical laboratories. By leveraging water‐wettable, hydrophilic‐lipophilic balanced copolymers and mixed‐mode phases, the Oasis product line enhances analyte retention, reduces matrix interferences, and accelerates workflows while ensuring reproducible recoveries.

Objectives and Study Overview

The primary goals of the manual are to present:

• Six complementary sorbent chemistries (HLB, PRiME HLB, PRiME MCX, MCX, MAX, WAX, WCX, GCB combinations).
• Generic and optimized SPE protocols for acidic, neutral, and basic analytes.
• Sample pre-treatment guidelines for biological, solid, aqueous, and non-aqueous matrices.
• High-throughput formats including cartridges, 96-well plates, and µElution plates.
• Application-specific methods such as multi-residue contaminant analysis, veterinary drug residue testing, QuEChERS integration, peptide bioanalysis, and PFAS monitoring.

Methodology and Instrumentation

The manual describes standardized SPE workflows:

• Conditioning, equilibration, loading, washing, and elution steps optimized by pH and organic solvent composition.
• 2-step pass-through and 3- to 4-step catch-and-release protocols tailored to sorbent type.
• Optimization strategies using multi-bottle pH/organic gradients (20-bottle optimization) for cleaner extracts.
• Device formats: traditional cartridges, Oasis PRiME plus light/short cartridges, 96-well plates, µElution plates.
• Instrumentation: vacuum manifold or positive-pressure systems, centrifuges, homogenizers, pipetting syringes, automated liquid-handling workstations.

Key Results and Discussion

Extensive testing demonstrates:

• Water‐wettable polymeric sorbents maintain higher recoveries even when run briefly dry, surpassing traditional silica phases.
• Oasis PRiME MCX protocols remove over 99% of phospholipids in biological extracts while delivering high and reproducible recoveries of basic analytes.
• Generic HLB methods can be further refined by adjusting pH and methanol concentration to maximize selectivity and minimize matrix noise.
• Dual‐phase WAX/GCB and GCB/WAX cartridges provide effective clean-up for per- and polyfluoroalkyl substances (PFAS) in accordance with regulatory methods (EPA 1633, ISO 25101/21675, EU standards).

Benefits and Practical Applications of the Method

These SPE approaches offer:

• Reduced solvent consumption and shorter preparation times by eliminating unnecessary conditioning steps (Oasis PRiME HLB).
• High throughput and reproducibility with 96-well and µElution formats, ideal for regulated bioanalysis and routine QA/QC.
• Broad applicability to food safety (veterinary drugs, pesticides, mycotoxins), environmental monitoring (water, soils), clinical bioanalysis (therapeutic peptides), and emerging contaminants (PFAS).
• Seamless integration with LC-MS/MS, GC-MS, and other detection platforms.

Future Trends and Potential Applications

Emerging directions include:

• Integration of automated SPE robotics with real-time method adjustment via machine-learning algorithms.
• Miniaturization of SPE formats for ultra-low volume bioanalysis and single-cell metabolomics.
• Development of novel sorbent chemistries targeting polar or highly lipophilic compounds in challenging matrices.
• Enhanced environmental monitoring protocols addressing next-generation contaminants and microplastics.

Conclusion

The Oasis family provides a comprehensive SPE toolkit that combines versatile chemistries with flexible device formats to meet diverse analytical challenges. By following the generic and optimized protocols, analysts can achieve high recoveries, superior clean-up, and consistent throughput across multiple application areas.

References

No formal literature list provided; methods and application notes referenced include Waters Oasis product brochures, EPA methods 533, 537.1, 1633, ISO standards 21675/25101, and various Waters application notes (e.g., 720006329, 720006787EN).