The benefit of binary pump stroke synchronization for more reliable peak identification based on improved retention time precision

Significance of the topic

Retention time stability is a cornerstone of reliable liquid chromatography workflows, particularly for peptide mapping in biopharmaceutical characterization and QC. Improved precision reduces misidentification risk, simplifies automated data processing, and enables cost-efficient workflows by allowing UV-based assays to replace routine MS once components are characterized. Enhancing retention time repeatability is therefore directly linked to method robustness, reproducibility in regulated environments, and operational cost savings.

Objectives and study overview

This application note evaluates the effect of binary pump stroke synchronization (HPG Sync) on UHPLC-UV peptide mapping performance. Using a cytochrome C tryptic digest as a model complex peptide mixture, the authors compared retention time precision and peak identification reliability with HPG Sync OFF versus ON across repeated injections over 24 hours (n=10). The goal was to demonstrate the practical advantages of stroke synchronization for challenging gradient separations and routine QC transferability.

Methodology

Sample preparation:

• Lyophilized cytochrome C digest reconstituted in 95% water/5% acetonitrile with 0.1% formic acid to 200 µL, vortexed and allowed to reconstitute ≥10 minutes.

Chromatographic method overview:

• Column: Hypersil GOLD Peptide, 2.1 × 150 mm, 1.9 µm.
• Mobile phases: A = water + 0.1% formic acid; B = acetonitrile + 0.1% formic acid.
• Flow rate: 0.25 mL/min; column temperature: 50 °C (still air) with 50 °C active pre‑heater.
• Injection volume: 10 µL; UV detection at 220 nm, 20 Hz acquisition.
• Gradient: extended multi-step gradient spanning approximately 115 minutes (early shallow slope, mid-range organic increase, and re-equilibration), designed to separate ~20 selected peptide components across the run.

Experimental design:

• Repeated sequence of injections (n=10) collected over 24 hours to assess retention time repeatability with HPG Sync OFF and ON.
• Retention times of 20 selected components were tracked and standard deviations calculated for each mode.

Data processing:

• Chromeleon CDS v7.4 was used for acquisition and analysis.

Instrumentation used

The study used a Thermo Scientific Vanquish UHPLC configuration with parts listed by module and part number. Key modules and components included:

• System base: Vanquish Horizon/Flex (VF-S01-A-02)
• Vanquish Binary Pump F (VF-P10-A-01) with HPG Sync option
• Vanquish Split Sampler FT (VF-A10-A-02)
• Vanquish Column Compartment H (VH-C10-A-03)
• Vanquish Variable Wavelength Detector F (VF-D10-A) with semi-micro bio flow cell (2.5 µL, 7 mm, PEEK; part 6077.0300)
• Viper capillaries and active preheater/post-column capillaries (various MP35N part numbers: 6752.1035, 6732.0700, 6732.0540)

Main results and discussion

Retention time precision:

• Average retention time standard deviation across 20 monitored components was reduced from ±0.023 minutes (HPG Sync OFF) to ±0.007 minutes (HPG Sync ON), representing more than a threefold improvement in repeatability.
• Improvements were evident across the gradient, both in early-eluting (components 1–5) and late-eluting regions, with overlayed chromatograms showing near-perfect superposition when HPG Sync was enabled.

Peak identification and robustness:

• The increased precision simplifies unambiguous peak matching to a pre-established LC-MS/MS identification map. With a user acceptance criterion of 0.03 minutes, both modes pass, but HPG Sync ON raises confidence and reduces borderline cases.
• Consistent injection timing (same camshaft position) reduces variability introduced by pump stroke timing differences, which is particularly beneficial for long gradients and narrow peaks characteristic of UHPLC peptide separations.

Operational impact and cost implications:

• By improving retention time stability, HPG Sync makes routine LC-UV peptide mapping more viable after initial MS-based component characterization, potentially lowering capital and operating costs compared with routine LC-MS use.
• Better repeatability supports automation and QC transfer, lowering rework and false identifications.

Benefits and practical applications

The study demonstrates concrete, practical advantages when HPG Sync is employed in peptide mapping workflows:

• Markedly improved retention time precision across a full gradient sequence, improving method robustness.
• More reliable and automated peak identification when using retention time matching to reference LC-MS/MS maps.
• Enables cost-efficient QC implementations that can rely on UV detection for routine checks after initial MS characterization.
• Facilitates method transfer into QC environments where reproducibility and automation compatibility are essential.

Future trends and possibilities of use

Anticipated developments and applications include:

• Wider adoption of stroke-synchronization and similar mechanical timing controls in binary and quaternary pump designs to boost retention time reproducibility for other challenging separations (e.g., small molecules with narrow peaks, lipidomics).
• Integration of retention time stabilization features with software-based retention time prediction and automated peak annotation to further reduce manual review.
• Broader replacement of routine MS-based assays by robust UV or PDA workflows for well-characterized targets, freeing MS resources for discovery and characterization tasks.
• Potential incorporation of synchronization data into system suitability criteria for regulated workflows, strengthening QC traceability.

Conclusions

Binary pump stroke synchronization (HPG Sync) on the Vanquish Binary Pump F significantly improves retention time repeatability in UHPLC peptide mapping, with an observed >3× reduction in retention time standard deviation in this study. The improved precision enhances peak identification confidence, supports automated workflows and QC transfers, and can reduce reliance on routine LC-MS, producing tangible cost and operational benefits for peptide mapping applications.

References

• Köhler D., Fabel S., Moebius J. The benefit of binary pump stroke synchronization for more reliable peak identification based on improved retention time precision. Thermo Fisher Scientific application note; 2026.
• Chromeleon Chromatography Data System, Thermo Fisher Scientific, version 7.4 (software used for data acquisition and analysis).