Chemical Analysis of Gunpowder and Gunshot Residues.

The identification of firearms is of paramount importance for investigating crimes involving firearms, as it establishes the link between a particular firearm and firearm-related elements found at a crime scene, such as projectiles and cartridge cases. This identification relies on the visual comparison of such elements against reference samples from suspect firearms or those existing in databases. Whenever this approach is not possible, the chemical analysis of the gunpowder and gunshot residue can provide additional information that may assist in establishing a link between samples retrieved at a crime scene and those from a suspect or in the identification of the corresponding model and manufacturer of the ammunition used.

Determination of phytocannabinoids in cannabis samples by ultrasound-assisted solid-liquid extraction and high-performance liquid chromatography with diode array detector analysis.

The characterisation of cannabis plants, especially the determination of specific phytocannabinoids, has gained enormous importance in the last decade, mainly due to the recent changes in cannabis control in several countries or states. This is particularly relevant for the forensic, medical or recreative industry to have a rapid, inexpensive, and reliable methodology to identify and quantify phytocannabinoids. Furthermore, spiking cannabis products with Δ-tetrahydrocannabinol (THC) is a contemporary trend that demands improving or replacing current methods to include this cannabinoid.

GC-MS Silylation Derivative Method to Characterise Black BIC Ballpoint 2-Phenoxyethanol Ratio Evaporation Profile-A Contribution to Ink Ageing Estimation.

One of the major challenges in forensic document analysis is estimating the age of ink deposition on a manually written document. The present work aims to develop and optimise a methodology, based on the evaporation of 2-phenoxyethanol (PE) over time, that can contribute to ink age estimation. A black BIC Crystal Ballpoint Pen was purchased in a commercial area, and ink deposition began in September 2016 over 1095 days.

Determination of Trace Levels of Irgarol in Estuarine Water Matrices by Bar Adsorptive Microextraction.

Bar adsorptive microextraction (BAµE), using selective sorbent phases, followed by liquid desorption in combination with large volume injection-gas chromatography coupled to mass spectrometry (BAµE-LD/LVI-GC-MS), is proposed for the determination of trace levels of irgarol in estuarine water matrices. While we compared several polymers and activated carbons, one of the latter coatings showed much higher selectivity through BAµE. Assays performed on 25 mL of ultra-pure water sample fortified at 0.