Evaluation of interferents in sampling materials for analysis of post-explosion residues (explosive emulsion/ANFO) using gas chromatography–mass spectrometry (GC/MS)

Abstract

Chemical analysis aimed at identifying post-explosion residues is critical for investigating crimes or accidents involving explosives, establishing it as a vital area of forensic chemistry. In general, only trace amounts remain in samples analyzed for this purpose, making the presence of interferents a constant concern. Therefore, understanding the materials used from collection to sample preparation is essential for this type of analysis. This study focuses on organic contaminants in collection and laboratory materials analyzed by gas chromatography/mass spectrometry (GC/MS), complementing a previous study by Mauricio et al. (2020), which addressed inorganic contaminants in materials used for similar purposes in ion chromatography (IC). No prior studies have specifically investigated the potential organic interferences introduced by various materials commonly used in forensic laboratories for sample pre-processing, storage, and evidence collection in this context. Plastic films, bottle caps, disposable gloves, syringes, swabs, disposable cups, plastic tubes, and plastic pipettes were examined. GC/MS analyses revealed that certain materials, particularly syringe plungers, gloves, and plastic films, can interfere with the detection of post-explosion residues from explosive emulsions and ANFO (ammonium nitrate-fuel oil). These findings emphasize the importance of evaluating materials for potential interferences prior to sample collection and processing to minimize contamination risks. This study provides significant insights into how commonly used laboratory materials can impact forensic analysis, thereby enhancing the reliability of post-explosion residue analysis and supporting more accurate forensic investigations.