Multiple Reaction Monitoring Tandem Mass Spectrometry Approach for the Identification of Biological Fluids at Crime Scene Investigations.

Knowledge of the nature of biofluids at a crime scene is just as important as DNA test to link the nature of the biofluid, the criminal act, and the dynamics of the crime. Identification of methods currently used for each biological fluid (blood, semen, saliva, urine) suffer from several limitations including instability of assayed biomolecules, and low selectivity and specificity; as an example of the latter issue, it is not possible to discriminate between alpha-amylase 1 (present in saliva) and alpha-amylase 2 (present in semen and vaginal secretion. In this context, the aim of the work has been to provide a predictive protein signature characteristic of each biofluid by the recognition of specific peptides unique for each protein in a single analysis.

Field detection capability of immunochemical assays during criminal investigations involving the use of TNT.

The capability to collect timely information about the substances employed on-site at a crime scene is of fundamental importance during scientific investigations in crimes involving the use of explosives. TNT (2,4,6-trinitrotoluene) is one of the most employed explosives in the 20th century. Despite the growing use of improvised explosives, criminal use and access to TNT is not expected to decrease.

An analytical approach to the forensic identification of different classes of new psychoactive substances (NPSs) in seized materials.

Rationale: New psychoactive substances (NPSs) are rapidly spreading worldwide, and forensic laboratories are often requested to identify new substances for which no reference standards or analytical data are available. This article describes an analytical approach that was adopted in Italy by a few collaborative centres of the Italian Early Warning System for Drugs, which has contributed many alerts for the identification of different classes of NPSs in the last 24 months.

Methods: Seized crystals and powders were initially analysed via single quadrupole gas chromatography/mass spectrometry (GC/MS), followed by liquid chromatography/high-resolution mass spectrometry (LC/HRMS) in the positive electrospray ionisation (ESI) mode at 100,000 full width at half maximum resolution (FWHM) without fragmentation to elucidate the elemental compositions of unknown molecules.

The discrimination potential of diffuse-reflectance ultraviolet-visible-near infrared spectrophotometry for the forensic analysis of paper.

The application of diffuse reflectance UV-VIS-NIR spectroscopy is proposed to differentiate 20 office paper samples, which had been deemed similar by a preliminary visual examination under several different lighting sources. The samples were firstly screened on the basis of the qualitative appearance of their spectra. A further discrimination was obtained by taking into account three parameters: the average reflectivity of the paper samples in the range 680-900nm, and the integrated intensity of the absorption peak in the UV range at 272nm and at 360nm.

Forensic differentiation of paper by X-ray diffraction and infrared spectroscopy.

The possibility to discriminate between sheets of paper can be of considerable importance in questioned document examinations. 19 similar types of office paper were characterized by infrared spectroscopy and X-ray diffraction to individuate the most discriminating features that could be measured by these techniques. The discriminating value associated to them was also assessed.