Honors Forensic Science Name: Miraflore Ndifon Hair Analysis for Heavy Metals General Background Detection of Heavy Metals in Hair Samples Heavy metal toxins such as arsenic and thallium commonly...

Forensic science


Honors Forensic Science Name: Miraflore Ndifon Hair Analysis for Heavy Metals General Background Detection of Heavy Metals in Hair Samples Heavy metal toxins such as arsenic and thallium commonly enters the body through ingestion . These toxins pass through the stomach and are absorbed by the blood stream. Once in the bloodstream, the toxins travel to all parts of the body. Heavy metals have a high affinity to bind to the amino acid cysteine Figure 1 : Cysteine, an essential amino acid. Keratin, the major structural protein in hair, contains many cysteine molecules, and therefore, is one of the main accumulation sites of these heavy metals. Figure 2 : Keratin, the major structural protein in hair. In simpler terms , heavy metal toxins like arsenic and thallium are “trapped” inside the keratin inside the strands of hair. Therefore, hair analysis is a great way to determine the presence of heavy metals in a person’s system. Figure 3 : Toxins trapped in the bloodstream are carried to the scalp. When at the scalp, the toxins are bound to the keratin, through the composite cysteine molecules, which makes up the structural integrity of a strand of hair. As the hair follicle grows, the trapped toxins are suspended in the individual strand of hair where they can then be detected through forensic toxicology analysis. Hair grows at approximately 1.3 cm /month . Hair keratin that is produced today will not protrude through the scalp for one week. This indicates that if a hair sample tests positive for toxins directly at root, the exposure occurred just one week prior. If the presence of heavy metal toxin does not appear until 1 inch away from the scalp, the exposure occurred 2 months prior, and so on. How to Analyze a Hair Sample 1. A hair sample is collected for analysis. Approximately 1 gram of hair is needed for analysis (this is about 2000-5000 strands of hair!). Hair found at the back of the head offers the best results for analysis . Why do you think the hair found here offers the best results? (take your best guess) 2. In the lab, the individual strands of hair are split and analyzed under a microscope. The microscopic analysis ensures there is a contaminant present in the hair and is in need of further elemental testing. 3. The overall chemical makeup of the hair is then identified using mass-spectrometry to determine the elemental analysis inside of the strands of hair. Procedure Using the patient’s symptoms and the chemical makeup of the toxic metals found in a hair sample, it is up to you to determine how the patient died. A male, aged 40, went to the hospital complaining of abdominal pains and muscle cramps, accompanied by overwhelming nausea and vomiting. While at the hospital, his health began to decline rapidly. His hands began to turn brown and scaly and his fingers and toes felt like they were always on fire. After a couple days, his body shut down resulting in a coma after he fell into cardiac arrest. The blood supply to his brain eventually stopped and his family decided that it was time to pull the plug. The hospital toxicologist knew they needed to perform an autopsy to determine that exact cause of death, although he already had an idea in mind. The toxicologist has suspicions that the patient was poisoned and sent samples of the patient’s hair to the lab for analysis. Below are the results the lab determined to in the chemical makeup of the patient’s hair sample: Lab Questions 1. What major symptoms did the patient exhibit that made the toxicologist believe the patient was suffering from a poisoning? 2. The reference interval is the maximum amount of heavy metal exposure a person can have in their