Direct Quantitation of Phosphatidylethanol (PEth) in Volume-Controlled Dried Blood Spots using the Fully Automated Transcend DSX-1 System

Importance of the Topic

Phosphatidylethanol (PEth) species are direct indicators of ethanol intake, with mid-term stability surpassing traditional markers. Dried blood spots (DBS) offer simplified storage, reduced biohazard risk and require minimal sample volumes, ensuring analyte stability and feasibility for large‐scale clinical and forensic applications.

Objectives and Study Overview

This work aims to demonstrate a fully automated workflow for the quantitation of PEth 16:0/18:1 directly from volume‐controlled DBS samples. The study evaluates method performance metrics relevant for clinical cut‐off requirements and highlights integration of sample spotting, extraction and analysis in the Transcend DSX‐1 system.

Methodology and Instrumentation

The procedure encompasses precise 10 μL blood spotting via HemaXis DB10 devices, ambient drying and automated extraction using Flow‐Through Desorption (FTD™) with HotCap™ heating. A built‐in pump delivers deuterated internal standard via Automated IS Addition (AISA™). Cleanup and separation employ TurboFlow™ online SPE in focus mode on a Vanquish UHPLC platform, followed by analysis on a TSQ Altis Plus triple quadrupole mass spectrometer in negative ESI mode.

Results and Discussion

The assay achieves an 8‐minute runtime with a linear calibration from 20 to 2000 ng/mL (R2>0.99). Within‐ and between‐day precision remains below 10% RSD and accuracy within ±10% at QC levels. Carryover is minimized through column selection and solvent switching. Automated imaging ensures spot recognition and traceability.

Benefits and Practical Applications

• High throughput analysis with minimal manual intervention
• Robust quantitation suited for clinical and forensic toxicology
• Enhanced traceability via integrated vision and chain‐of‐custody control
• Efficient use of small sample volumes with stable dried matrix format

Future Trends and Possibilities

Emerging directions include multiplexed biomarker panels, integration with point‐of‐care platforms, advanced data analytics incorporating machine learning for pattern recognition, and expansion to other small‐molecule assays in dried matrices.

Conclusion

The fully automated Transcend DSX‐1 workflow streamlines DBS preparation and LC‐MS/MS quantitation of PEth, delivering reliable, high‐throughput performance ideal for routine alcohol monitoring.

References

1. Javors M. A. et al. Alcohol Clin. Exp. Res. 2016;40(6):1228–1234
2. Viel G. et al. Int. J. Mol. Sci. 2012;13(11):14788–14812