Having your cake and eating it, too: A novel quantitative LC-HRAM bile acids workflow incorporating robust quantitative and discovery capabilities

Importance of the topic

Bile acids (BAs) are increasingly recognized as biologically important metabolites with roles in host metabolism, signaling, microbiome interactions and diverse disease processes. Reliable, quantitative measurement of bile acids and their numerous conjugates remains challenging in non-targeted metabolomics due to poor fragmentation, wide chemical diversity and lack of standardized workflows. A robust, transferable assay that combines rigorous quantitation with high-resolution discovery capability can improve reproducibility across laboratories and accelerate biomarker discovery and mechanistic studies.

Objectives and overview of the study

This work describes Move Analytical’s MoveKit BA and MoveApp workflow that merges a gold-standard quantitative LC-MS assay for bile acids with non-targeted high-resolution accurate mass (HRAM) data acquisition. Goals were to: provide an easy-to-implement kit-and-software solution for absolute bile-acid quantification across labs; retain flexibility for semi-quantitative and discovery analyses from HRAM MS/MS data; and enable rapid, automated data quality assessment and reporting.

Methodology and workflow

Key elements of the method:

• Standards and calibration: Matrix-based calibrators and multi-point QC materials were prepared from pooled biological matrices spiked with unlabeled bile-acid mixes and stable isotope labeled (SIL) internal standards. MoveKit BA supplies the required reagents and standards.
• Sample preparation: A 96-well plate workflow uses methanol containing SIL bile acids, ammonium acetate as an aqueous focusing reagent, and glass-fiber filter plates. Typical sample handling: 140 µL extraction reagent, 20 µL specimen, 40 µL focusing reagent, chill and filter (shake 15 min) optimized for high throughput.
• Chromatography and acquisition: Reversed-phase separation on a Waters BEH C18 column with a 9.5-minute gradient at 0.3 mL/min; inject-to-inject cycle circa 10 minutes. HRAM MS/MS data collected on Thermo Orbitrap and Stellar mass spectrometers.
• Quantitation strategy: Single-Point External Calibration (SPEC) combined with multi‑point QCs in the kit. Matrix-based calibrators were demonstrated to provide superior recovery and accuracy versus aqueous or MeOH/water calibrators. SPEC was validated against multi-point linear calibration with bias within 20%.
• Software workflow: MoveApp supports experiment design, rapid sequence generation, automated data acquisition, system suitability checks (SST), automated data checks, processing (~15 min), quantification, QC visualization, and report/statistical outputs.

Used instrumentation

• Mass spectrometers: Thermo Scientific Orbitrap platforms and Stellar mass spectrometers.
• Chromatography: Waters BEH C18 column.
• Consumables and kits: MoveKit BA (Move Analytical LLC) including SIL standards (CIL), unlabeled mixes (CIL, IROA, Cayman, Bileomix), glass fiber filter plates and reagents.

Main results and discussion

Coverage and throughput

• The workflow targets 16 conjugated and non‑conjugated bile acids plus sulfated analogs and reports coverage figures such as 32 fully quantitative bile acids and up to ~155 compounds when combining quantitative and semi-quantitative targets.
• Throughput is high: ~10 minutes per sample inject-to-inject and plate processing times of under 30 minutes per 96-well plate for extraction steps.

Calibration and QC performance

• Matrix-based single-point external calibration (SPEC) with in-kit multi-point QCs gave comparable accuracy to multi-point calibration while simplifying routine implementation. Most calibration points showed bias within 20% versus traditional multi-point linear curves.
• MoveApp provides automatic visualization and QC monitoring (QC low/high accuracy, study pool performance, linear dynamic range) enabling rapid identification of common issues such as pipetting bias, carryover, or sample-prep failures.

Cross-laboratory validation and peak assignment

• Method cross-validation was performed across six laboratories using different Orbitrap and Stellar instruments. For datasets that passed the MoveApp data check, automatic assignment of six critical bile-acid chromatographic pairs was consistently correct; explicit iRT-based approaches showed much poorer inter-lab robustness.
• Automated peak assignment and reporting were achieved in seconds per sample; full processing and review remained fast (~15 min), supporting operational QC rather than forensic post hoc assessment.

Benefits and practical applications

• Operational ease: Packaged reagents, standards and an integrated software workflow reduce method transfer burden between labs.
• Quantitative rigor: SIL internal standards, matrix-based calibration, and embedded multi-point QCs deliver reliable absolute quantification suitable for comparative research and preclinical studies.
• Discoverability: HRAM MS/MS acquisition preserves the ability to detect and semi-quantify additional bile and fatty acid species beyond the quantitative panel, supporting biomarker discovery.
• Quality management: Automated SST and QC dashboards enable rapid decision-making and early intervention to prevent costly failures.
• High throughput: Short gradients and plate-friendly sample prep allow scaling to larger cohorts with rapid turn-around.

Future trends and potential applications

• Standardization and interoperability: Wider adoption of matrix-based SPEC and packaged kits could improve comparability of bile-acid data across laboratories and studies.
• Library expansion: Extending the quantitative library (more conjugates, sulfates, microbiome‑derived BA species) will broaden biological insight.
• Integration with informatics: Direct LIMS integration, automated statistical pipelines and improved spectral libraries will streamline routine clinical‑research workflows.
• Automation and miniaturization: Further automation of sample prep and on-instrument data checks will reduce hands-on time and variability.
• Translational studies: Broader deployment in microbiome/metabolome research, pharmacokinetics, and biomarker validation cohorts.

Conclusion

The MoveKit BA and MoveApp workflow demonstrate a practical compromise between rigorous quantitative bile-acid measurement and flexible HRAM discovery. By combining matrix-based calibration, SIL internal standards, short LC gradients, and integrated QC/processing software, the approach achieves high throughput, cross-laboratory robustness and retains the ability to discover semi-quantitative analytes. This package lowers the barrier to reproducible bile-acid profiling in multi-site studies and supports operational QC practices that facilitate early troubleshooting.

Reference

No formal literature references were provided in the source poster. Acknowledgements and product statements from Move Analytical, Thermo Fisher Scientific and collaborating organizations were included. The materials are for research use only and not for diagnostic use; patent applications are pending.