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Aaron Acevedo is an assistant editor for LCGC and Spectroscopy at MJH Life Sciences.

Articles

Scientists at West Virginia University have created a new LIBS system meant to better identify the components of gunshot residue at crime scenes and in evidence.

Portable LIBS Paves the Way for More Effective Gunshot Residue Testing

Spray paint is often used by vandals for creating graffiti, as well as for criminals to leave signs, messages, and blots to conceal the left traces at the scene of their efforts. Rajinder Singh and his colleagues in the Department of Forensic Science at Punjabi University (Punjab, India) have used attenuated total reflectance Fourier transform infrared (ATR-FT-IR) spectroscopy for nondestructive analysis of 20 red spray paints of different manufacturers, which could possibly be encountered at a crime scene, particularly in case of vandalism. Singh spoke to Spectroscopy about the findings, and the paper that resulted from their efforts.

Chemometric Analysis on ATR-FT-IR Spectra of Spray Paint Samples for Forensic Purposes 

An ongoing challenge within the forensic science community is the development of consistent report and testimony language that conveys results in a meaningful manner.

Developing More Uniform Comparison Language in Forensic Science Reportings

Confocal Raman Microscopy in Forensic Pharmaceutical Investigations

The isotopic profile of a material refers to the ratios of the stable isotopes of elements contained within, such as 2H/1H, 13C/12C, and 18O/16O. Biological, chemical, and physical processes cause variations in the ratios of stable isotopes; analysis of a material for its distinctive isotopic signature can thus be used to reveal information about its history. Isotope ratio mass spectrometry (IRMS) is a technique used to measure the relative abundance of isotopes in materials. Forensic investigators have used IRMS to measure a variety of materials, such as drugs, explosives, food, and human remains. In a recent web seminar, Lesley Chesson, the president of IsoForensics, Inc., explained how IRMS works and discussed the use of IRMS in forensic science, illustrating her discussion with several case examples.

Forensic Applications of Isotope-Ratio Mass Spectrometry

Recent advances in Raman instrumentation have resulted in the development of easy-to-use and efficient handheld Raman analyzers. Most of the commercially available handheld Raman devices utilize 785 or 1064 nm excitation. This paper directly demonstrates the performance of 532 nm handheld Raman (versus 785 and 1064 nm) for the analysis of biopharmaceuticals for structure and counterfeit testing as well as explosive detection (TSA screening and CSI applications). The results presented here will contribute to recognition of 532 nm Raman excitation as a highly attractive option for a rapid “in-place” analysis in the field.

Recent Developments in Handheld Raman Spectroscopy for Industry, Pharma, Forensics, and Homeland Security: 532-nm Excitation Revisited

Forensic Applications of Isotope Ratio Mass Spectrometry

The analysis of hair samples is gaining increasing interest in forensic science because of several advantages. Hair samples are easy to collect and store. The keratin protein in hair is also quite stable, and the amino acid composition of human hair keratin may vary significantly between individuals. Glen Jackson of West Virginia University has been developing various mass spectrometry (MS)-based methods for forensic analysis of hair samples, and he recently spoke to us about this work.

Advancing the Forensic Analysis of Hair

A huge amount of information is contained in the FTIR spectra of soils in the mid infrared (MIR) region (4000 to 400 cm-1). The spectra provide an overall chemical profile of the soil, encompassing fundamental vibrations of both the organic and mineral components. Interpretation of the spectrum of individual soils can provide a powerful means of differentiating between samples and therefore has considerable potential for use in forensic applications, and indeed we have successfully used laboratory-based FTIR analysis of soil to provide evidence in forensic casework. In recent years handheld FTIR spectrometers have become available and this makes it possible for in situ or field-based FTIR analysis of soils at a crime scene. However, reliable and tested protocols are not yet available for field-based FTIR analysis of soil. This paper discusses the sampling options for field-based FTIR of soil and describes tests of the methodology we are developing, for a handheld FTIR, on soil samples tested in the context of a mock crime scene.

In Situ FTIR Analysis of Soils for Forensic Applications

Enzyme immunoassay (EIA) is a conventional drug screening technique, but it can be limited by cross-reactivity that can lead to high false positive rates.

Forensics, Narcotics