Mass Spectrometry

Learn Something New Every Day – (Lecture 11) Mass Spectrometry

You see TV characters waving test results around and talking loudly about the mass spectrometer (a forensic machine-that-goes-ping) but have you ever looked up exactly what this is?

Without getting technical (please Lord don’t require that!), a bunch of smart people fire a laser through the gas that is created when a forensic sample is heated up and emulsified down, the resulting elements are weighed and their atomic charge is taken.

While someone wipes all the emulsified goo out of the machine, those elements are measured and assigned a ratio of MASS:CHARGE. That goes along the bottom of a chart and the quantity of the element in the sample is reflected in the STRENGTH of the spike for that element.

The resulting pattern of ‘ingredients’ (by mass, charge and strength) are a visual signature for a chemical looking like a series of spikes along an axis. A drug fingerprint, if you like. Toxicologists learn hundreds (even thousands) of these prints at a glance and are able to determine the exact makeup of any substance.

‘Trails of Evidence: How Forensic Science Works” is a The Great Courses DVD lecture series