Deuterium is particularly useful to forensic scientists.It is naturally occurring and very stable, meaning it is found in water in varying amounts, and, critically, those variations depend on the source of the water.The body was badly decomposed, dental records didn't reveal anything, and a widely circulated composite sketch and description of her personal effects yielded no valuable information. Seven years later, there were still no leads in the case.Desperate for a break, the state medical examiner released a sample of Saltair Sally's long, blonde hair to be tested by stable isotope analysis, a new forensic technique that had been introduced in the years since Saltair Sally had been discovered.In October 2000, a pair of duck hunters in Utah stumbled into a murder mystery.
Every molecule in our bodies—including those found in hair—are made up not just of different elements, but of different ratios of stable isotopes of those elements. In its most common form, it has one proton and one electron.
There are also two less common isotopes, deuterium and tritium, which have one and two neutrons, respectively, in addition to their proton and electron.
Since our drinking water comes from rainwater, people near the coasts drink water with more oxygen-18 atoms in it than people living inland.
Those atoms eventually become a part of our tissues, like hair.
Lesley Chesson works at Salt Lake City-based Iso Forensics, the company that received the hair sample.
"It was our first case, where we really got started," says Chesson, an analytical chemist. " Such clues would give investigators valuable information as they continued to search for the victim's identity.