Visit Your Local PBS Station PBS Home PBS Home Programs A-Z TV Schedules Watch Video Donate Shop PBS Search PBS
home about the series timeline of the pharaohs historical maps digging deeper secrets and science resources
Secrets and Science
Intro Mass Spectrometry Extracting Mummy DNA Deciphering Disease in Ancient Mummies Limits of the New Science
Mass Spectrometry: Deciphering the Elements

Holding a sample with tweezers For the most part, the techniques scientists use to identify narcotics and other drugs from the hair and tissue of a mummy and chemical compounds from a plant like the Egyptian blue lotus (as seen in the SECRETS OF THE PHARAOHS episode "Unwrapping the Mummy") are the same. Researchers Vic Garner and David Counsell of the University of Manchester relied on a sophisticated version of a common chemical analysis technique: mass spectrometry.

Mass spectrometry, developed in the early 20th century, sorts the different kinds of molecules in compounds -- be they opiate drugs, cannaboids and caffeine, plant steroids and bioflavinoids like those found in the blue lotus, poisons like arsenic and lead, or even single atoms of gases like helium, carbon, and neon. The molecules can then be characterized and their concentrations determined. Even the individual isotopes of an atom -- varieties of an atom that have the same chemical properties but different mass, like carbon-12 and carbon-14 -- can be identified with mass spectrometry. The biggest and most elaborate mass spectrometers can analyze bits of material just a few millionths of an inch across, and sort molecules that differ in mass by just one part in several thousand. The technique is useful not just in chemical analysis, toxicology, and drug testing, but has wide applications in fields like geophysics, geochemistry, astronomy, and environmental monitoring of pollution.

When Garner and Counsell did their evaluation of the blue lotus, they tested two different types of samples. Ancient tomb and temple paintings and carvings indicated that the Egyptians inhaled the perfume of the flower, perhaps to induce some hallucinogenic or otherwise altered state. So Counsel and Garner studied the molecules that made up the "fragrance" of the flower -- essentially, gas pulled from the air space above the open flower. Other scenes showed the blue lotus added to wine and then drunk, so the researchers also tested an extract of molecules released by the flower after it had been soaked in methanol. Both types of samples, liquid and gas (as well as solids), can be analyzed using mass spectrometry.

Egyptian blue lotus In the procedure, a small amount of the item to be analyzed is placed into a chamber and then blasted with a high-energy beam of negatively charged electrons, the particles that make up an electric current. The beam ionizes the molecules in the sample, turning them into positively and negatively charged ions of various types and sizes. The ions are then swept through a curved tube by a magnetic field, toward a detector. The field sorts the ions based on their mass and charge. Heavier ions, for example, are less deflected by the magnet and will take a wider path, so they take longer to slam into the detector. Each ion that is in the sample will produce a peak on a graph. The size of the peak indicates its relative concentration, and from the pattern of peaks, researchers can decipher what sorts of chemicals were in the original sample.


Secrets of the Pharaohs