Mass spectrometry

Mass spectrometry is an analytical technique that identifies chemical compounds by ionising a sample and separating the resulting ions by their mass-to-charge ratio, generating a fragmentation pattern that can be matched against reference libraries. It is the reference standard for compound identification in forensic toxicology, laboratory drug checking, and pharmaceutical quality analysis.

In practice it is almost always coupled with a prior chromatographic separation — most commonly gas chromatography (GC-MS) or liquid chromatography, often run twice in sequence (LC-MS/MS). The separation stage resolves a complex mixture into its components before the spectrometer analyses each one individually.

What this design can establish

A well-run mass spectrometry analysis can establish with high confidence whether a specific compound is present in a sample and, when the instrument is calibrated against verified reference standards, at what approximate concentration. The fragmentation pattern — sometimes described as a compound's chemical fingerprint — is distinctive and stable enough that a match to a reference standard carries legal weight in forensic settings.

For drug checking, this means it can detect fentanyl or its analogues in a powder sold as something else, identify novel psychoactive compounds that fall outside common reagent-test panels, and document adulterants a person would otherwise have no way of knowing were present.

In supply monitoring research, systematic mass spectrometry data across a population of tested samples can characterise how a street supply changes over time — which analogues are circulating, which adulterants appear together, how concentrations shift across batches.

What it cannot

Mass spectrometry establishes what is present; it says nothing about what that presence will do to a person. A positive identification carries no information about the biological activity of the detected compound, the concentration required to produce effects, the threshold for harm, or how any individual will respond.

The most common wrong inference is to treat identification as a safety assessment. Knowing a sample contains a given compound establishes only that it is there — not that any particular quantity is safe or dangerous. Dose, route of administration, and individual tolerance are questions outside the scope of the technique.

It also cannot detect compounds it has not been configured to recognise. A result that finds nothing unusual is only as reliable as the reference library the instrument checks against. A novel analogue not yet in that library may produce an unmatched fragmentation pattern that is flagged as unknown, mis-assigned to a structurally similar compound, or missed altogether — depending on how the analysis is configured.