High-throughput Single Cell Lipidomics LCMS/ MS Workflow Using the Xevo™ MRT P10 Mass Spectrometer

Significance of the topic

This application note presents a practical, high-throughput LC-MS/MS workflow for single-cell lipidomics that combines analytical-flow UPLC with a novel high-resolution Xevo MRT P10 mass spectrometer. Moving lipidomics from bulk to single-cell resolution addresses biological heterogeneity that is invisible in population-averaged measurements and enables new insights in cell biology, disease mechanisms and translational research. The workflow emphasizes accessibility (no nanoflow chromatography required), throughput (6.5 min injection-to-injection), contamination control and confident lipid annotation via high mass accuracy.

Study aims and overview

The study aimed to develop and validate a reproducible, sensitive single-cell lipidomics pipeline that:

• performs single-cell isolation and extraction with minimal sample handling and contamination risk;
• uses an analytical-flow LC method to enable high throughput while retaining single-cell sensitivity;
• provides confident lipid identifications using high-resolution MS and established data-processing tools.

The workflow was demonstrated on two intestinal epithelial cell lines (Caco-2 and HT29-MTX) with emphasis on throughput, annotation confidence and practical robustness.

Methodology and sample handling

Single cells were obtained using the isoPick single-cell pickup system following standard cell-culture and trypsinization procedures. Cells were deposited directly into pre-chilled glass Qsert vials to minimize plastic leachables and background contamination. A one-step extraction in the same vial using ice-cold MS-grade isopropanol spiked with the EquiSPLASH deuterated internal standard mix minimized transfers and sample loss. Samples were stored at –80 °C until analysis to preserve integrity. Ten microliters of each extract were injected for LC-MS analysis.

Used instrumentation

• LC: ACQUITY Premier UPLC System with Flow-Through Needle (FTN) autosampler.
• Column: ACQUITY Premier CSH Phenyl-Hexyl, 2.1 × 50 mm, 1.7 µm, operated at 70 °C.
• Chromatography: analytical-flow (0.7 mL/min) fast gradient producing a 6.5 min injection-to-injection cycle; mobile phases water/ACN-based with 0.1% formic acid and 1 mM ammonium formate (ACN used instead of IPA to lower backpressure and enable multi-omics).
• MS: Xevo MRT P10 mass spectrometer operated in positive ion mode with MSE (data-independent acquisition) continuum: 50–1200 Da, 10 Hz scan rate, capillary 2.8 kV, sampling cone 40 V, desolvation 500 °C, desolvation gas 750 L/hr, cone gas 50 L/hr, CE ramp 20–40 eV.

Data processing workflow

Raw data were converted to mzML using waters_connect and processed in Lipostar. Feature detection filters included MS and MS/MS thresholds and an S/N cutoff (S/N > 3). Lipid annotation used LIPID MAPS Structure Database with a 2 ppm MS tolerance; annotations were retained above a mass score cutoff and manually reviewed using spectra and retention time. Normalization and QC employed the EquiSPLASH deuterated standards, with transitions generated via LipidCreator and internal-standard visualization in Skyline. Multivariate statistics were performed within Lipostar2.

Main results and discussion

• Sensitivity and throughput: The analytical-flow LC method coupled with Xevo MRT P10 provided a 6.5 min cycle time while maintaining chromatographic resolution suitable for single-cell lipid detection.
• Identifications: The workflow produced hundreds of tentative lipid features covering major lipid classes (PC, PE, PI, PG, PS, SM, CE, TG, DG, ceramides); the application note reports over 180 reproducible identifications at single-cell level and ~80 high-confidence annotations with mass errors < 1 ppm. In some processing stages >300 tentative annotations were observed before manual curation.
• Fragmentation and confidence: MSE-derived fragment ions (e.g., diagnostic PC headgroup m/z 184 and neutral-loss patterns for TG/DG) combined with sub‑ppm precursor mass accuracy increased assignment reliability. Example: TG(60:9) showed matched fragment at m/z 705.582 with error < 500 ppb.
• Chromatographic advantages: The phenyl-hexyl CSH phase provided π–π interactions useful for lipid retention and potential positional isomer discrimination. Using ACN rather than IPA reduced column backpressure, improving robustness for analytical-flow operation and facilitating multi-omics flexibility.
• Contamination control: Use of pre-chilled glass vials, one-pot extraction, rapid freezing and minimized handling were critical to reduce background signal at single-cell equivalent concentrations.
• Biological comparability: Caco-2 and HT29-MTX single-cell extracts yielded similar lipid-class distributions with ceramides, DGs and TGs prominent, and a broad representation of phospholipids.

Benefits and practical applications

• High throughput suitable for studies requiring many single-cell measurements (6.5 min cycle time).
• Analytical-flow approach eliminates many practical limitations of nanoflow LC (lower maintenance, reduced pressure, greater robustness) while achieving single-cell sensitivity.
• High mass accuracy (<1 ppm) and DIA fragmentation improve confidence in lipid identifications for discovery and targeted follow-up.
• Accessible to laboratories with standard cell-culture capabilities and moderate LC-MS expertise; minimal bespoke hardware required beyond single-cell picker if shipping is available.

Future trends and potential applications

Expected developments and uses include:

• Further automation of single-cell isolation and liquid handling to increase throughput and reduce variability.
• Expanded spectral libraries and AI-assisted annotation to improve identification depth and isomer resolution.
• Integration with single-cell transcriptomics and proteomics for multi-omics cell-state mapping; the ACN-compatible method facilitates polar metabolite co-analysis.
• Targeted single-cell quantitation using isotope-labeled standards and scheduled MS/MS for robust biomarker studies.
• Improved chromatographic phases and acquisition strategies for routine positional isomer separation at single-cell scale.

Conclusion

The described workflow demonstrates that analytical-flow LC coupled with a high-resolution Xevo MRT P10 MS can deliver reproducible, high-confidence lipidomic profiles at the single-cell level while offering high throughput and practical robustness. Critical enablers are stringent contamination control, single-vial extraction, use of deuterated internal standards for normalization and high mass accuracy combined with DIA fragmentation for confident annotation. The approach broadens accessibility of single-cell lipidomics to more laboratories and supports integration into multi-omics pipelines.

Reference

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