Chromatography Series: New Year Edition
Accurate Alcohol Testing in Blood & Urine – The Role of Sample Preparation
After the champagne corks have popped and the fireworks faded, forensic and clinical labs kick into high gear. Reliable determination of ethanol (and sometimes methanol or other congeners) in blood and urine is essential for traffic safety, workplace testing, postmortem investigations, and emergency toxicology.
Why Sample Preparation is Critical
Biological matrices are notoriously “dirty”: proteins, phospholipids, salts, and endogenous compounds can suppress signals, foul columns, and shorten instrument lifetime. Direct injection often leads to poor peak shape, ion suppression in LC-MS/MS, or ghost peaks in headspace-GC. Clean, reproducible sample preparation is therefore non-negotiable.
Headspace-GC-FID – Still the Gold Standard
For legal blood-alcohol cases, HS-GC with internal standard (usually t-butanol or acetonitrile) remains the reference method in most countries. Urine ethanol is increasingly used as a secondary matrix because it reflects a longer detection window and is non-invasive.
Analytical Approaches in Practice
Headspace GC (HS-GC-FID/HS-GC-MS) remains the reference method for legal blood-alcohol determinations in many regions. LC-MS/MS is gaining ground in high-throughput laboratories, especially when combined with fast sample-prep workflows such as protein precipitation, SLE, or SPE. This also enables determination of EtG, EtS, and other alcohol biomarkers.
Orochem Solutions for Alcohol Testing
Through our partnership with Orochem, we offer reliable tools for efficient and reproducible sample preparation:
- Oro-Sep™ — SPE Cartridges: Traditional C18, reversed-phase, and mixed-mode SPE cartridges for cleanup and concentration prior to LC or GC.
- Aquamatrix — Supported Liquid-Liquid Extraction (SLE): Plates and cartridges designed for fast, emulsion-free extraction — ideal for automated and high-throughput LC-MS/MS workflows.
- Chastity — Phospholipid Depletion (PLD) Plates & Cartridges: Targeted removal of phospholipids and proteins to reduce matrix effects and extend column lifetime.
- Protein Precipitation Plates: A simple, cost-effective approach for dilute-and-shoot LC-MS/MS workflows, often used in combination with SLE or SPE.
RubyPro Protein Crash Plate
Practical New Year’s Workflow Tips
- Use HS-GC for legally defensible blood-alcohol cases.
- For high-throughput screening: protein precipitation → Aquamatrix SLE or Oro-Sep SPE → LC-MS/MS.
- Apply Chastity PLD when phospholipids cause matrix-related issues.
Whether you are running 50 samples or 500 after New Year’s Eve, clean sample prep means faster runtime, fewer re-runs, and results you can defend when it matters most.
Here’s to a safe, well-calibrated, and analytically sound 2026 — may your baselines be flat and your recoveries high!
For more information, please contact Iben Kofoed Piper.
