Forensic Mass Spectrometry: Scientific and Legal Precedents

Mass spectrometry has made profound contributions tothe criminaljustice system by providing an instrumental method of analysis thatdelivers exquisite analytical figures of merit for a wide varietyof samples and analytes. Applications include the characterizationof trace metal impurities in hair and glass to the identificationof drugs, explosives, polymers, and ignitable liquids. This reviewdescribes major historical developments and, where possible, relatesthe developed capabilities to casework and legal precedents. Thisreview also provides insight into how historical applications haveevolved into, and out of, modern consensus standards. Unlike manypattern-based techniques and physical-matching methods, mass spectrometryhas strong scientific foundations and a long history of successfulapplications that have made it one of the most reliable and respectedsources of scientific evidence in criminal and civil cases. That said,in several appellate decisions in which mass spectrometric evidencewas challenged but admitted, decisions sometimes still went againstthe mass spectrometric data anyway, which goes to show that mass spectrometricevidence is always just one piece of the larger legal puzzle.

Automated summary

Mass spectrometry has significantly contributed to the criminal justice system by offering precise analytical methods and reliable scientific evidence. It has been applied to a wide range of samples and analytes, from trace metal impurities to drugs, explosives, polymers, and ignitable liquids. This review discusses the historical developments, connects them to real cases, and explores the evolving consensus standards. Although mass spectrometry has a strong foundation and a successful track record, it is just one piece of the legal puzzle, as evidenced by some appellate decisions that did not solely rely on the mass spectrometric data.