Effect of Liner Properties on the Analysis of Lysergic Acid Diethylamide (LSD) Analogs

LSD and related psychedelic drugs are often present at low concentrations on forensic evidence, requiring sensitive detection. The liner inside the injection port of a gas chromatograph (GC) affects how well these compounds are vaporized and transferred to the column. Testing twelve different liners—varying in shape, packing material, and chemical deactivation—showed that liners containing packing material (like glass wool) produced significantly higher peak areas than unpacked liners. Liner geometry had a smaller effect, only mattering with one deactivation type when glass wool was absent. Base deactivation improved peak area compared to standard and Topaz deactivation in straight liners with packing. Over seventy sample runs, base-deactivated and standard liners maintained consistent response, while Topaz-deactivated liners lost 52–68% response after the first injection and 30–54% from first to last injection.

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 material, and deactivation chemistries were assessed by analyzing a mixture of eight LSD related compounds and comparing the average peak areas. Liners containing packing material led to significantly higher responses than those without. Liner geometry 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 seventy samples. Response with base deactivated liners and liners with standard deactivation remained consistent over time, whereas the liner with Topaz deactivation decreased in response 52 % to 68 % after the initial injection and demonstrated a decrease in response of 30 % to 54 % from the first injection to the final injection.