Surface analysis techniques have rapidly evolved in the last decade. Some of these are already routinely used in forensics, such as for the detection of gunshot residue or for glass analysis. Some surface analysis approaches are attractive for their portability to the crime scene. Others can be very helpful in forensic laboratories owing to their high spatial resolution, analyte coverage, speed, and specificity. Despite this, many proposed applications of the techniques have not yet led to operational deployment. Here, we explore the application of these techniques to the most important traces commonly found in forensic casework. We highlight where there is potential to add value and outline the progress that is needed to achieve operational deployment. We consider within the scope of this review surface mass spectrometry, surface spectroscopy, and surface X-ray spectrometry. We show how these tools show great promise for the analysis of fingerprints, hair, drugs, explosives, and microtraces.

Illegal trafficking of pharmaceutical products by criminal organisations is a global threat for public health. Drugs for erectile dysfunction such as phosphodiesterase type 5 inhibitors are the most commonly counterfeited medicines in Europe. The search of possible toxic chemical substances in seized products is needed to provide early warning for public health. Furthermore, the elemental profile of the seized products can be useful in criminal investigations. For the first time an ion beam analysis (IBA) procedure to characterise authentic Viagra® tablets and sildenafil-based illegal products is described. Moreover, results are compared with the ones obtained by instrumental neutron activation analysis (INAA) on authentic Viagra® tablets in two reactors. IBA results showed that a combination of particle-induced X-ray emission (PIXE) and secondary ion mass spectrometry using primary ions with energies in the range of several MeV (MeV-SIMS) is a powerful tool to characterise different products in a straightforward manner, allowing discrimination between legal and illegal products. INAA allowed accurate elemental quantification and also showed a great potential for the future implementation of an inter-laboratory classification system.

A crucial part of any chemical analysis is the degree of representativeness of the measurand(s) in the test portion for the same measurands in the object, originally collected for investigation. Such an object usually may have either to be homogenized and sub-sampled, or digested/dissolved. Any of these steps introduce sampling errors, risk of contamination or loss of the measurand(s). Neutron (and photon) activation analysis and prompt gamma analysis have the capabilities of analyzing large objects or samples without the need of any pre-treatment, i.e., intact 'as received', with masses varying from tens of grams to tens of kilograms, and with any type of (irregular) shape. The basic concept of neutron activation analysis and prompt gamma analysis are shortly revisited and the scope of application of the large sample analysis with these technique are elaborated on with an outlook for use in forensic studies, including the analysis of medicinal products and drugs of abuse.