Homogeneity assessment of the elemental composition of windshield glass by µ-XRF, LIBS and LA-ICP-MS analysis

Laser Emission Spectroscopy of Graphene Oxide Deposited on 316 Steel and Ti6Al4V Titanium Alloy Suitable for Orthopedics

This paper presents the results of an analysis of carbon (in the form of graphene oxide) deposited on the surface of threads made from stainless steel 316 and titanium alloy Ti6Al4V used in orthopedics using Laser Induced Breakdown Spectroscopy (LIBS). The aim of the article is to indicate the possibility of using the LIBS spectra for the study of thin layers, including graphene derivatives and other elements. Stratigraphic measurements allowed the detection of differences in the spectra peaks of individual elements, not only in the surface layer itself and in the native material, but also in the intermediate layer connecting the two layers. Due to the clear difference in the outline of the spectrum of graphene oxide and the spectrum of the native material of the samples analyzed, a clear incorporation of carbon atoms into the surface layer was observed. A factor analysis was performed, which confirmed the incorporation of graphene oxide into the surface layer of the native material of the elements examined.

The analysis of glass from portable electronic devices and glass accessories using µ-XRF for forensic investigations

In this study, glass from 30 different portable electronic devices (PED) screens, 15 screen protectors (SP), and 3 brands of liquid glass (LG) were analyzed using a µ-XRF instrument equipped with two silicon drift detectors (SDD). Additional analysis of six fragments, all originating from the same PED and SP screen, assessed the elemental homogeneity within a single glass source. Examinations of the 30 PEDs and the majority of the SP screens revealed spectra with low sodium and high potassium, which is likely due to the ion exchange process at the surface during the glass manufacturing process. The absence of calcium in the XRF spectra was also characteristic of PED formulations. Initial spectral overlay examinations classified the PED and SP samples into major groups based on their distinctive elemental profiles (5 PED groups, 4 SP groups). Further discrimination of within-group samples was possible when considering reproducible differences in signal intensities (discrimination 98.4 % PED, 98.1 % SP). Additionally, a 3 s (3 % Relative Standard Deviation, RSD) comparison criterion produced the lowest false exclusion rates among same-source fragments (3.3 % PED, 0.8 % SP) while maintaining a high discrimination power among different-source fragments (98.4 % PED, 100 % SP). Same source PED and SP samples resulted in low variability within most elements examined (< 8 % RSD), except for potassium. An experimental threshold established from the quantitative metric of spectral similarity, spectral contrast angle (SCA) ratio of same-source and different-source datasets, produced false exclusion and false inclusion rates of 4 % or 0.95 % for PED and SP fragments, respectively. Spectra of just the liquid glass residues indicated some major elements present but the effect of these elements in PED fragments treated with liquid glass was not significant. This study provides a preliminary understanding of the elemental composition of modern PED glasses and their accessories and the discrimination capability of µ-XRF for forensic comparisons.