There are often reports about clues to understand the cause of death and environmental pollution sources through hair measurement. For example, the University of Glasgow in the United Kingdom analyzed the hair left by Napoleon who died more than 100 years ago and found that it contained extraordinary amounts of arsenic. It is believed that Napoleon died of arsenic poisoning, not of stomach cancer as recorded in encyclopedia americana. Indian women like to mark their foreheads with red pigment containing lead, which affects the fetus through maternal absorption. The lead content in newborn hair is hundreds of times higher than that of normal people. As for the pollution of tetraethyl lead to urban children, hair lead is higher than that of rural children and adults.
Detection of trace and macro elements in hair combined with blood type test can provide strong evidence for criminal technical analysis. Many diseases related to trace elements can also be found in hair. Chinese medicine theory also believes that hair is related to blood and kidney, which is called "hair outside blood" and "kidney in hair". Yellow hair reflects weakness and malnutrition, which has also become an intuitive indicator of Chinese medicine. By detecting trace elements in hair, it can provide a lot of useful information for disease diagnosis, etiology discussion and course development. Because hair detection is highly technical, and there are many external interference and variation factors, the controversy about the detection value of trace elements in hair at home and abroad reached its peak in the mid-1980 s. With the improvement of the sensitivity and accuracy of detection instruments and the deepening of the basic research on the application of trace elements, a series of reliable hair detection methods and sampling comparison rules have been recognized internationally, which makes the application of hair analysis in clinical medicine develop rapidly. In 1990s, the value of hair testing has been gradually accepted by people. Scientists in the United States and China found that the selenium content in hair and serum of patients with Keshan disease and cancer was significantly lower than that of healthy people. Chinese experts also found that zinc, as an important trace element in life, is related to the activities of more than 80 enzymes in human body. Children with severe zinc deficiency will have symptoms such as anorexia, growth retardation and mental retardation, and the zinc content in their hair is significantly lower than that of healthy children.
Through the atomic absorption spectrum analysis and detection of trace elements in hair and serum, we can understand the nutritional status of trace elements in human body, correct bad eating habits, guide the application of trace element drugs and health care products, and play an important role in human health.