High-Throughput LNP Compositional Analysis Using GTxResolve™ RP 230 Å PH+ Columns: Robustness and Reproducibility

Significance of the topic

Lipid nanoparticles (LNPs) are central to modern RNA therapeutics and vaccines; accurate, high-throughput compositional analysis of their lipid constituents (ionizable lipids, cholesterol, helper phospholipids, PEGylated lipids) is critical for formulation development, stability assessment and routine quality control. As ionizable lipid chemistries diversify, analytical platforms must deliver fast, robust separations with reproducible retention and resolution to support screening campaigns and regulatory workflows.

Objectives and overview of the study

This application note evaluates a new reversed-phase column (GTxResolve RP 230 Å PH+) tailored for lipid analysis. Key aims were to demonstrate: reproducible column-to-column and batch-to-batch performance; high-throughput capability (4 min assays) with full separation of four principal LNP lipid classes; robustness under stress (500 injections); and performance relative to a legacy fully porous CSH Phenyl‑Hexyl phase.

Methodology and experimental design

• Sample preparation: Two representative mixtures were prepared in methanol: a canonical mixture (cholesterol, DLin‑MC3‑DMA, ALC‑0159 (PEGylated), DOCPe) for UV-detectable components, and a complex LNP/ionizable lipid mixture including multiple ionizable lipids (DLin‑MC3‑DMA, ALC‑0315, C12‑200), DSPC, PEGylated lipid and a diluted Moderna COVID‑19 vaccine as a source of SM‑102. Stocks (1–10 mg/mL) were sonicated, stored at −20 °C and diluted for injection.
• Chromatographic conditions: GTxResolve RP 230 Å PH+ column (SPP, 1.6 µm, 230 Å), 2.1 × 50 mm, column temp 40 °C, sample temp 20 °C, injection 3 µL. Mobile phases: A = 0.1% formic acid in water; B = 0.1% formic acid in MeCN. Flow 0.4 mL/min (resolving) or 1.0 mL/min (high-throughput). Two method regimes were used: a high-throughput 4 min gradient (tg ≈ 2 min) and a slower resolving gradient (10–15 min).
• Detectors: UV at 205 nm for UV‑active lipids and ELSD for non‑volatile, weakly UV‑absorbing lipids. CAD compatibility noted (conditions described in referenced work).

Used Instrumentation

• LC system: ACQUITY Premier UPLC System (Waters).
• Columns: GTxResolve Lipid Phenyl‑Hexyl+ RP Column, MaxPeak Premier Technology, SPP, 1.6 µm, 230 Å, 2.1 × 50 mm (p/n: 186011698).
• Detectors: SEDEX 85 LT‑ELSD (Sedere) with drift tube 40 °C, gain 7, nebulizer gas 48 psi; ACQUITY UPLC TUV detector (205 nm, 10 mm path, 500 nL FC volume).
• Consumables: QuanRecovery vials with MaxPeak HPS low‑adsorption surfaces; MaxPeak HPS hardware to reduce carryover.

Main results and discussion

• Separation performance: The GTxResolve RP 230 Å PH+ column achieved baseline or near‑baseline separation of canonical LNP components under both high‑throughput and resolving conditions. Ionizable lipids eluted earlier (electrostatic repulsion from positively charged surface) while hydrophobic phospholipids eluted last.
• Speed and efficiency: The superficially porous, wide‑pore particle design enabled high linear velocities and efficient mass transfer, producing a full four‑component discrimination in as little as 4 minutes at 1 mL/min. Under resolving conditions (longer gradient), peak capacity was 37–40.
• Reproducibility: Column‑to‑column reproducibility (same lot) showed maximum retention time RSD = 1.1% and mean peak area RSD ≈ 9% (high‑throughput); resolving methods gave retention RSD ≤ 1.0%. Batch‑to‑batch comparisons across four lots produced maximum retention RSD = 0.7% and mean peak area RSD ≈ 6.3%, with only modest variation in DSPC peak width (batch effect ~13% RSD under unoptimized conditions).
• Robustness / lifetime: An accelerated stress test of 500 consecutive injections of a complex LNP matrix using the high‑throughput method showed minimal retention time drift and little peak distortion without intermediate column cleaning. Authors recommend periodic cleaning (e.g., 100% isopropanol or buffered methanol) in routine sequences to prolong lifetime.
• Comparison to legacy fully porous phase: Relative to an ACQUITY Premier CSH Phenyl‑Hexyl fully porous column (130 Å, 1.7 µm), the GTxResolve column enabled approximately 50% faster separation of a critical pair (cholesterol vs PEGylated lipid) and produced a markedly sharper PEGylated peak (~75% narrower), improving selectivity and throughput.
• Detection notes: ELSD method optimization may be necessary to avoid low‑intensity spikes due to formulation excipients (e.g., sucrose) and to stabilize area precision.

Benefits and practical applications of the method

• High throughput: Enables rapid screening of LNP formulations and combinatorial ionizable lipid libraries, reducing development timelines.
• Robust QC performance: Consistent retention and resolution across columns and batches support routine release testing and method transfer.
• Broad applicability: Compatible with UV, ELSD and CAD detection modes, allowing analysis of both UV‑active and non‑volatile lipid species typical in LNPs.
• Platform potential: The column chemistry and particle design are suitable for establishing platform methods for LNP compositional assays, balancing electrostatic and hydrophobic interactions for predictable selectivity.

Future trends and potential applications

• Detector integration and automation: Wider adoption of CAD/ELSD automation and software workflows will streamline quantification of non‑volatile lipids and improve throughput.
• Method extension for diverse ionizable lipids: As ionizable lipid chemistries evolve, guided method development (varying ionic strength, pH modifiers, organic co‑solvents) will be required to tune electrostatic/hydrophobic interplay for optimal separation.
• Regulatory and lipidomics demands: Growing regulatory guidance for mRNA/LNP quality and expanding lipidomics will increase demand for robust, transferable, high‑throughput assays.
• Integration with characterization suites: Combining fast LC separations with orthogonal detectors (MS, ELSD, CAD) and sample preparation automation will support comprehensive formulation profiling and impurity monitoring.

Conclusion

The GTxResolve RP 230 Å PH+ column delivers reproducible, high‑efficiency separations of LNP‑relevant lipids with significant throughput and robustness advantages over legacy fully porous phenyl‑hexyl phases. Superficially porous 230 Å particles with a phenyl‑hexyl ligand and acid‑activated positive surface charge enable fast discrimination of cholesterol, ionizable, PEGylated and phospholipid classes, with strong column and lot reproducibility and good tolerance to complex LNP matrices. The column is well suited for method development, high‑throughput screening and routine QC assays in LNP development workflows.

References

1. Zhang M., Van L., Amiji M.M. Pharmacometric Modeling of Lipid Nanoparticle‑Encapsulated mRNA Therapeutics and Vaccines: A Systematic Review. Mol. Ther. Nucleic Acids. 2025;36:102686.
2. Li P., Sun Z., Chen X., Shao Q., Wu H. Mapping Current Research Status and Emerging Frontiers of Lipidomics: A Comprehensive Data‑Mining‑Based Study. Metabolomics. 2025;21:85.
3. United States Pharmacopeia (USP). Analytical Procedures for Quality of mRNA Vaccines and Therapeutics, Draft Guidelines, 3rd ed., USP–NF. 2024.
4. Naidu G.S., Rampado R., Sharma P., et al. Ionizable Lipids With Optimized Linkers Enable Lung‑Specific, Lipid Nanoparticle‑Mediated mRNA Delivery for Treatment of Metastatic Lung Tumors. ACS Nano. 2025;19:6571–6587.
5. Birdsall R., Du X., Bigos P., Han D., Bhiwankar N. Automating Charged Aerosol Detection (CAD) Analysis With Empower CDS Software Using a Single‑Vendor Integrated LC Platform. Waters Application Note. 2026.
6. Alden B.A., Isaac G., Chen W., Lauber M.A. Lipid Nanoparticle Compositional Analysis Using Charged Surface Hybrid Phenyl‑Hexyl Separation With Evaporative Light Scattering Detection. Waters Application Note. 2021.
7. Almeling S., Holzgrabe U. Use of Evaporative Light Scattering Detection for the Quality Control of Drug Substances: Influence of Different Liquid Chromatographic and Evaporative Light Scattering Detector Parameters on the Appearance of Spike Peaks. J. Chromatogr. A. 2010;1217:2163–2170.
8. Imiolek M., Koza S.M. High throughput LNP Compositional Analysis using GTxResolve RP 230 Å PH+ Columns: Method Development Considerations. Waters Application Note. 2026;720009411.