Effect of liner properties on the analysis of lysergic acid diethylamide ( LSD ) analogs

LSD and related compounds are often present at low concentrations on forensic evidence, requiring sensitive detection methods. The inlet liner of a gas chromatograph—a consumable component that vaporizes samples—can affect how well these compounds are detected. Testing twelve different liners with a mixture of eight LSD-related compounds showed that liners containing packing material (like glass wool) produced significantly larger peak areas than unpacked liners. Liner geometry had a minor effect, only mattering with one deactivation type when glass wool was absent. Base deactivation improved peak area over standard and Topaz deactivation in straight packed liners.

Study at a glance

Abstract

Lysergic acid diethylamide (LSD) and analogs are psychedelic drugs commonly submitted to forensic chemistry laboratories. These drugs are often present on items of evidence at low concentrations, requiring sensitive analyses to positively identify their presence. The injection port of a gas chromatograph (GC) plays an important role in vaporizing and transferring substances to the column for separation and subsequent detection. The consumables in the inlet, specifically the liner, can influence the abundance and chromatography of compounds being analyzed. Twelve liners with varying geometries, packing materials, and deactivation chemistries were assessed by analyzing a mixture of eight LSD-related compounds and comparing the average peak areas. Liners containing packing materials yielded significantly higher peak areas as compared to those without. The geometry of the liner played a smaller role and affected results only with one deactivation when glass wool was not present. Base deactivation improved peak area when compared to standard and Topaz deactivation in straight liners with packing. Authentic samples were analyzed on liners with varying deactivation chemistries to determine the effect over a run of seven replicates of 10 street samples (70 sample injections). Peak area with base-deactivated liners and liners with standard deactivation remained consistent over time, whereas the liner with Topaz deactivation decreased in peak area 52-68% after the initial injection and demonstrated a decrease in peak area of 30-54% from the first injection to the final injection.