How is hair tissue mineral analysis performed? This might be a mixed chemistry / physics question, but I've always wondered what methods were used to precisely determine the levels down to trace amounts of all minerals in human tissues. I know there's a tissue preparation phase, in which I am interested though less than in the details of the actual final testing methods and processes to determine those trace amounts of all minerals.
The analytical technique is called inductively coupled plasma optical emission spectroscopy. It was invented by a chemist V. A. Fassel, although it is pure physics. The specimen is digested in an acid, and a fine spray is created. That "spray" is heated to a temperature, which is higher than the surface of the Sun. Most of the elements of the periodic table emit specific wavelengths in that hot plasma- the characteristic emission of each element is just like a fingerprint. Not all elements can be detected easily but it is very good for metals. This is the mineral analysis. Organic analysis is even more complicated and it is a separate story.