In 1994, China University student Zhu Ling began to experience stomach pain, hair loss and partial parsley. When doctors had a diagnosis of Ling with multium poisoning about four months later, she was in a coma. Ling survived, but she was suffering from permanent neurological harm. An investigation by the police decided that Wen had been poisoned and deliberately, but the case remains unresolved.
Two decades after poisoning, Ling's family association, asked Richard Ash, an associate research scientist at the Department of Geology of the University of Maryland, to analyze a number of Ling lambs that were collected in 1994 and 1995 to establish a timeline of poisoning. Although Ash specializes in the analysis of geological samples, it often helps a variety of researchers by analyzing tracking elements in samples that use mass spectrometry, a technique that can measure elements in the parts per billion levels.
In October 2018, Ash published the results in the magazine International Forensic Science, revealing for the first time that the victim be exposed to multiple doses of acne over a long period.
"In my view, this is the first use of mass spectrometry to reconstruct a long-term heavyweight metal poisoning timeline," said Ash. "The analysis showed that the victim was poisoned in many times that often increased and concentrated over time."
Mass spectrometry makes even even low concentrations of sodium in hair, but measuring the amount of odium in a hair sample is challenging. Other laboratories dropped Min He, the Ling family who joined the author of the Ash study, because there was no fixed method for this type of analysis. "Mass spectrometry is not good when measuring concentrations," says Ash. "To do this, you need standardized standard reference material to compare your sample against.
And no such standards are suitable for measuring talium concentrations directly from a hair strand. "
Ash made its own standard using standard reference material made from the orchard leaves, developed by the National Institute and National Technology (NIST) to measure some elements in biological samples. Ash added the amounts of known acne to the NIST material to create a new set of standards that allowed him to determine how much odium was in the victim's hair.
As an additional level of quality control, Ash proved its measurements that resulted from the NIST standard against the Chinese powder hair standard and found that its measurement of elements in victim hair corresponds closely to & # 39; Some in the powder hair standard.
"To be honest, I was surprised that the new standard worked so well," said Ash. "Developing my own standard was shooting in the dark, but paid it."
Next, Ash took advantage of the fact that human hair grows-and incorporates chemicals of the body-at a constant rate. Due to this characteristic, the measurement of specific metals distribution along hair length is an established method to determine the timing and dosage of a person's exposure to the metal.
To measure talaium in the victim's hair, Ash scanned the length of the hair with an ultraviolet laser. Laser energy transferred the most perfect layer of hair into small particles. Ash then used mass spectrometer to analyze particles for talium. Using the growth rate and the speed of laser scanning, Ash made its measurements into a timeline of a talaium attack.
Ash used this technique to analyze a number of victim guides, collected at different times in 1994 and 1995. One hair that began to grow when Ling was asymptomatic revealed about four months of severe exposure to acumum, with increasing dose and frequency until the hair dropped in December 1994. Second hair, which expired around March 1995, showed about two weeks of a constant holding of large doses.
Ash also discovered a large spin in a talium concentration in the first hair that was a short period of time when Ling was suffering from visual loss but no symptoms on the seizure. As noted by the study, this perception suggests that the victim could have been poisoned by eye contact at the beginning, but later, was poisoned by oral assault.
By publishing its method and its findings, Ash hopes that his work can help with investigations of heavy metal poisoning in the future – and perhaps even the decades case that he presented to this field of research in the first place.
"I hope that the new information our work will have provided maybe one day will lead to the offender being brought to justice and that the Zhu Ling family have some reason to see that," said Ash.
Hair substances can be a signer for drinking alcohol
Richard David Ash et al, Details of the cause of multium poisoning disclosed by a single hair analysis using plasma mass spectrometry to connect to laser abstraction plasma, International Forensic Science (2018). DOI: 10.1016 / j.forsciint.2018.10.002