Determination of seventeen major and trace elements in new float glass standards for use in forensic comparisons using laser ablation inductively coupled plasma mass spectrometry.

Consensus concentration values for seventeen (17) major and trace elements typically present in soda-lime glass manufactured using the "float " process and used in the quantitative analysis and forensic comparison of glass samples were determined using laser ablation (LA) micro sampling coupled to inductively coupled plasma mass spectrometry (ICP-MS). This is the first reporting of the chemical characterization of a new set of float glass intended for use as matrix-matched calibration standards in the forensic analysis and comparison of glass by LA-ICP-MS using a standard test method (ASTM E2927-16e1). Three Corning Float Glass Standards (CFGS) were manufactured at low, medium, and high concentrations of 32 elements typically encountered in float glass samples as found in forensic casework.

An interlaboratory study evaluating the interpretation of forensic glass evidence using refractive index measurements and elemental composition.

Seventeen laboratories participated in three interlaboratory exercises to assess the performance of refractive index, micro X-ray Fluorescence Spectroscopy (μXRF), and Laser Induced Breakdown Spectroscopy (LIBS) data for the forensic comparison of glass samples. Glass fragments from automotive windshields were distributed to the participating labs as blind samples and participants were asked to compare the glass samples (known vs. questioned) and report their findings as they would in casework.

Development of tailor-made inorganic gunshot residue (IGSR) microparticle standards and characterization with a multi-technique approach.

The forensic analysis of inorganic gunshot residues (IGSR) involves analytical measurements from samples taken from skin and other substrates. The standard practice for IGSR analysis recommends the use of Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDS) to identify the gunshot residues using combined information of the particle's morphology and elemental composition. However, the current deficit on IGSR standard reference materials (SRM) limits the optimization of SEM-EDS for modern, lead-free ammunition and the development of emerging analytical techniques.

Cross-validation and evaluation of the performance of methods for the elemental analysis of forensic glass by μ-XRF, ICP-MS, and LA-ICP-MS.

Elemental analysis of glass was conducted by 16 forensic science laboratories, providing a direct comparison between three analytical methods [micro-x-ray fluorescence spectroscopy (μ-XRF), solution analysis using inductively coupled plasma mass spectrometry (ICP-MS), and laser ablation inductively coupled plasma mass spectrometry]. Interlaboratory studies using glass standard reference materials and other glass samples were designed to (a) evaluate the analytical performance between different laboratories using the same method, (b) evaluate the analytical performance of the different methods, (c) evaluate the capabilities of the methods to correctly associate glass that originated from the same source and to correctly discriminate glass samples that do not share the same source, and (d) standardize the methods of analysis and interpretation of results. Reference materials NIST 612, NIST 1831, FGS 1, and FGS 2 were employed to cross-validate these sensitive techniques and to optimize and standardize the analytical protocols.