Mass spectrometry (MS) is known as “the near-universal test for identifying unknown substances.” For decades, forensic teams have used MS to identify drugs in and outside the body. Scientists today still consider this method the gold standard instrumental analysis tool.
The Evolution of Forensic Mass Spectrometry
In the early twentieth century, forensic pathologists could not have imagined that the complex, expensive process would become so widely used within 100 years. As it is with so many scientific discoveries, however, the right tool in the right hands makes all the difference. As MS evolved, the process became more straightforward and less expensive. Scientists have developed uses for MS beyond drug identification, as well.
Notable Mass Spectrometry Developments
In 1929, American physicist Walker Bleakney (1901-1992) worked alongside other leading physicists to develop one of the first mass spectrometers. At first, the devices were limited to gas and inorganic vapor analysis.
By the mid-1940s, mass spectrometers became commercially available, though they were unwieldy, expensive, and cumbersome to use. Thanks to the work of physicists John Beynon (1923-2015) and Fred McLafferty (b.1923), MS capabilities expanded to organic material analysis.
A significant breakthrough happened in 1968 when FDA scientists Robert Martin and Thomas Alexander applied a high-resolution MS technique involving “crackling patterns.” By 1968, mass spectrometers could analyze natural products and botanical extracts, including:
Lysergic acid diethylamide (LSD)
Mescaline, psilocin, and psilocybin
Crime Scene Analysis
In 1959, a firearms technician at the Chicago police crime lab discovered that gas chromatography-MS (GC-MS) tests could be used to analyze suspected arson evidence. The tests were used to examine fire debris to determine whether accelerants had been used to start fires.
Forensics teams used similar GC-MS applications to study gunshot residue and explosives found at crime scenes. The test was revolutionary when it came to piecing together how firearms had been used in violent crimes.
Earlier forensics techniques could reveal whether a gun had been fired through a test that involved coating a suspect’s hand with hot paraffin wax and conducting a color test. However, these tests were generally considered unreliable. GC-MS techniques allowed forensics analysts much more detailed information about gun residue.
In 1970, a team of MS experts at the Massachusetts Institute of Technology (MIT) developed a type GC-MS that could reverse the effects of a drug overdose. A patient suffering from a Darvon overdose recovered as a result of this new technology.
Within a year, the Fales’ group at the National Institutes of Health (NIH) was able to reverse more than 100 overdose cases with GC-MS. These treatments were made possible through advances in databasing, which allowed them to analyze blood serum and stomach contents with much more precision.
These MS techniques paved the way for the advent of forensic toxicology. By 1972, toxicologists were applying MS “fragmentography” to identify drugs in near real-time. This method eliminated the need for time-consuming sample preparation.
Notably, fragmentography allowed scientists to detect alcohol in circulating blood for the first time.
Mass Spectrometry Analysis Becomes More Precise
In 1973, a team of Swedish scientists developed a GC-MS assay that could detect whether someone had smoked “one half-billionth of a gram” of Tetrahydrocannabinol (THC) through blood analysis.
GC-MS made the news when it was used to screen athletes’ blood during the 1972 Olympic Games in Munich. The screenings revealed that 18 athletes were using illegal substances, leading to disqualifications and extended international debate.
MS Gains Widespread Acceptance
MS data produced by the Environmental Protection Agency (EPA) was considered so precise by 1977 that it was admitted as evidence in a court case. The analysis showed the existence of a pesticide in the tissue of animals from the Siuslaw National Forest in Oregon.
Other high profile evidentiary uses include a capital murder case in 1978 and a court case involving the American Meat Institute. Attorneys in this case claimed that MS analysis should be entered into evidence because it was “widely regarded as the best available technology” at the time.
Toward the end of the 1970s, MS analysis was becoming more widely known among police departments. Although it was considered the most accurate technique available, it was too slow and expensive to become commonplace.
Still, forensic detectives were eager to bring the technology on board as soon as possible. A survey of 100 crime labs in 1973 revealed that mass spectrometers were the most desired piece of equipment.
As scientists fine-tuned the GC-MS process, forensic laboratories started investing in the technology, which is now commonplace throughout the world.
Trace Fibers and Hair Analysis
Scientists developed MS methods for analyzing hair and fiber for trace-level inorganic impurities as early as the 1930s, when iron was separated from hair through chemical extraction. By the early 1960s, scientists were able to use MS to detect heavy metals like iron and copper in trace fibers, as well as mercury and lead exposure.
A type of MS was used to match a strand of a suspect’s hair with hairs discovered at a crime scene where an explosive had been used in 1977. This early usage was considered reliable, but it did not become a generally accepted scientific method until a few years later. Today, fiber and hair analysis is commonly used to solve complex crimes.
Mass Spectrometry Today
The field of mass spectrometry continues to develop and attract researchers. The American Society of Mass Spectrometry (ASMS) annual meeting draws thousands of participants each year for a 5-day event focused on MS techniques and developments.
Mass spectrometry has gained a resurgence in popularity thanks in part to advances like desorption electrospray ionization (DESI) which relies on vacuum and direct analysis in real-time (DART). MS as an approach has not been replaced by new science; it has simply evolved. The early emergence of MS as a trustworthy tool for chemical analysis led directly to MS as it used today.
When it comes to providing reliable forensic evidence, mass spectrometry remains the gold standard.
Interested in other history?
Leybold is celebrating 170 years of pioneering the development of vacuum technology. You can read about our journey through time, and the many industries we impact today (including mass spectrometry) here