Elemental analysis and imaging of sunscreen fingermarks by X-ray fluorescence.

Chemical composition in fingermarks could provide useful information for forensic studies and applications. Here, we evaluate the feasibility of analysis and imaging of fingermarks via elements by synchrotron radiation X-ray fluorescence (SRXRF) and commercial X-ray fluorescence (XRF). As a proof of concept, we chose four brands of sunscreens to make fingermarks on different substrates, including plastic film, glass, paper, and silicon wafer.

Fluorescence development of fingerprints by combining conjugated polymer nanoparticles with cyanoacrylate fuming.

Selecting appropriate developing methods/reagents or their combination to enhance the effect for fingerprint development is of great significance for practical forensic investigation. Ethyl-2-cyanoacrylate ester (superglue) fuming is a popular method for "in-situ" developing fingerprints in forensic science, followed by fluorescence staining to enhance the contrast of the fingerprint image in some occasion. In this study, a series of fluorescent poly(p-phenylene vinylene) (PPV) nanoparticles (NPs) in colloidal solution were successfully prepared and the emission color was tuned via a simple way.

Fluorescence Development of Latent Fingerprint with Conjugated Polymer Nanoparticles in Aqueous Colloidal Solution.

Poly(p-phenylenevinylene) (PPV) nanoparticles in aqueous colloidal solution have been prepared via a modified Wessling method, with the addition of surfactant. The fluorescent colloidal solution was used as the developing solution to develop the fingerprints on different substrates. The developing process was accomplished simply by immersing the substrates into developing solution and then taking out, followed by rinsing with deionized water.