Development of a Stable Matrix-Matched Standard for Molecular and Elemental Analysis of Hair in Forensic Toxicology

In forensic toxicology, human hair is routinely analyzed for the detection of drugs and their metabolites. Hair analysis is useful due to non-invasive sample collection and large detection window of weeks to months. Human hair as a biological matrix provides a temporal record of analytes in the body. Current methods by liquid chromatography mass spectrometry (LC-MS) for drug detection and metal poisoning in human hair utilize time-consuming sample preparation and large amounts of sample. Thus, quantification of toxic exposure in hair can be studied by direct sampling by laser analysis.

Laser-based analysis can provide direct sampling of hair with limited sample and minimal sample destruction, a phenomenon crucial in forensic investigations. For these techniques, it is necessary for a standard that is matrix-matched, lacking in forensic analysis. Thus, there is a need for the development of a matrix-matched analytical standard for chemical profiling of human hair to minimize sample matrix effects. Matrix assisted laser desorption/ionization-mass spectrometry (MALDI-MS) imaging is a growing technology in forensic investigations, providing label-free identification and imaging of analytes by direct analysis. Elemental analysis of human hair by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) provides longitudinal determination of exposure over time with high sensitivity.

This study utilizes the analysis of a synthesized reference material extracted from human hair keratin. This reference material will be characterized and spiked with heavy metals and drug metabolites. Therefore, this study will focus on the development of a calibration standard for molecular and elemental analysis by MALDI-MS imaging and LA-ICP-MS.

This project will provide the forensic community with a reliable, rapid, and quantitative method for the determination of toxic metals and drug metabolites in human hair. This method can define the protocol for molecular and elemental analysis of human hair for forensic toxicology casework. CA/NCF