SOLAμ Solid Phase Extraction (SPE) well plates technical guide

Significance of the Topic

Bioanalytical laboratories face the challenge of extracting and quantifying trace-level analytes from complex biological matrices using minimal sample and solvent volumes while maintaining high throughput and regulatory compliance. SOLAµ micro-elution SPE plates address these demands by offering a robust, frit-less sorbent design that enhances reproducibility and sensitivity.

Objectives and Study Overview

The aim of the study was to demonstrate that SOLAµ well plates can:

• Deliver high reproducibility in low-volume extractions
• Enhance assay sensitivity through micro-elution concentration
• Enable direct scaling down of sample volumes without losing performance
• Eliminate evaporation steps that risk analyte loss
• Maintain compatibility with high-throughput workflows

Methodology and Instrumentation

SOLAµ plates integrate support material and active media into a uniform sorbent bed, removing the need for frits and ensuring consistent flow even at low bed weights. Key procedural steps included sample dilution with phosphoric acid, sorbent equilibration, controlled loading at 0.5 mL/min, sequential washing, and low-volume elution (25–50 µL) directly into LC-MS systems.

• HPLC System: Thermo Scientific Dionex UltiMate 3000 RSLC
• Analytical Column: Thermo Scientific Accucore RP-MS, 50 × 2.1 mm, 2.6 µm
• Guard Cartridge: Accucore RP-MS Defender in Uniguard drop-in holder
• Mass Spectrometer: Thermo Scientific TSQ Vantage Triple Quadrupole

Main Results and Discussion

• Sensitivity Gain: Loading 500 µL human plasma and eluting in 25 µL achieved a 20× concentration factor with precision below 2% RSD for niflumic acid.
• Volume Reduction: Direct use of 25 µL sample with 25 µL elution yielded equivalent performance to a 250 µL conventional SPE method, maintaining precision around 1% RSD.
• Elimination of Dry-Down: Ibuprofen extraction from plasma achieved a 4× pre-concentration without evaporation, preserving analyte integrity and delivering >90% recovery with RSD <4%.
• Loading Capacity: Recovery and matrix effect assessments for atenolol and imipramine across 50–500 µL loads remained within acceptable limits, demonstrating robust analyte retention.

Benefits and Practical Applications

• Robust SPE performance at low sample and solvent volumes
• High-throughput compatibility with minimal workflow changes
• Enhanced assay sensitivity via micro-elution concentration
• Prevention of analyte loss by eliminating evaporation steps

Future Trends and Potential Applications

Ongoing developments may include integration with automated liquid-handling systems, expansion to novel sorbent chemistries for emerging biomarkers, adaptation to diverse biological matrices, and coupling with next-generation mass spectrometers for deeper sensitivity and multiplexed analyses.

Conclusion

SOLAµ solid phase extraction well plates provide a versatile, reproducible, and efficient platform for modern bioanalytical workflows, enabling significant sensitivity gains and low-volume processing without compromising data quality or throughput.