Trace element detection methods

Accurate detection of trace elements in the human body is the premise and foundation of any theoretical research and clinical application, if there is no accurate detection, it is impossible to talk about research and application. Although trace element research began in the 1970s, it is, after all, a new discipline, the means of detecting trace elements is still relatively old and backward, from sampling to pre-test processing to testing until the results of the analysis, need to be operated by professionals, the steps are quite complex, serious contamination, and the results of a long period of time. This is one of the important reasons why hospitals are unable to popularize trace element testing. With the continuous improvement of medical level, the relationship between trace elements and human health has been fully recognized, people are more concerned about how to supplement trace elements and how to eliminate harmful elements. Trace elements are a balanced process in the human body, and both deficiency and excess of trace elements will have adverse effects on the human body. Therefore, how to accurately, quickly and conveniently detect the content of trace elements in the human body has become an urgent issue for medical workers. \x0d\ At present, China's health care units at all levels, especially maternal and child health care units, children's hospitals, general hospitals, etc., has been the human body elements (lead, zinc, copper, calcium, magnesium, iron, etc.) testing as a routine program. The following is an introduction to the methodology of trace element testing. \x0d\1, the traditional methods of trace element testing. \x0d\ Currently available methods for trace element detection in the human body are: radionuclide dilution mass spectrometry, molecular spectroscopy, atomic emission spectrometry, atomic absorption spectroscopy, X-ray fluorescence spectrometry, neutron activation analysis, biochemical analysis, electrochemical analysis and so on. However, biochemical method, electrochemical analysis method, and atomic absorption spectrometry are the most widely used methods in clinical medicine. The following is a brief introduction to the main features of the two methods of biochemical and electrochemical analysis. \x0d\(1) The characteristics of biochemical method: the amount of blood used in the specimen is large, requires pre-treatment, operation is complicated, clarification of serum is time-consuming; the detection of serum by the influence of the recent diet so that the data lack of objectivity and accuracy; the cost of reagents is higher, the detection of the elements of a limited variety. \x0d\(2) Characteristics of electrochemical analysis: can be used for trace measurements, but the error is large; poor reproducibility when determining a variety of elements; serious contamination of the environment and laboratory personnel; pre-treatment is extremely cumbersome and time-consuming; experiments are sometimes difficult to control so that the results are often unstable. \x0d\2, atomic absorption spectrometry. \x0d\ so-called atomic absorption spectrometry (atomicabsorptionspecoscopy, AAS) also known as atomic absorption spectrophotometry, usually referred to as the atomic absorption method, the basic principle is: from the hollow cathode lamp or light source emits a beam of a specific wavelength of the incident light in the atomizer in the element to be measured in the basal state of the atomic vapor on which the absorption, the unabsorbed The unabsorbed portion is transmitted through. The amount of light absorbed at a specific wavelength is measured to determine the content of the element to be measured. The quantitative relationship of atomic absorption spectrometry can be expressed by the Lombard-Beale law, A-abc. Where A is the degree of absorption, a is the absorption coefficient, b is the optical path length of the absorption cell, and c is the concentration of the sample to be measured. The method is characterized by high sensitivity and accuracy; good selectivity and less interference; fast speed and easy automation; many measurable elements and wide range; simple structure and low cost. \x0d\1955, after the birth of atomic absorption spectrometry, because of its strong vitality, rapidly applied to the analysis of chemical palms in various fields, the domestic large-scale application is in the 1990s began, the most widely used is metallurgy, geological exploration, quality inspection and supervision, environmental testing, disease control and so on. Atomic absorption spectrometry in the Center for Disease Control is as the "gold standard". With the progress of clinical medicine, atomic absorption spectrometry detection of trace elements in the clinic has been widely used. \x0d\ atomic absorption spectrometer according to the atomization of different ways can be divided into flame atomic absorption and graphite furnace atomic absorption. Graphite furnace atomic absorption requires instantaneous high current, requiring the system to have a high anti-interference ability. With the development of science and technology, the world's major manufacturers have begun to achieve a fully integrated design, all the spectral detection system, flame, graphite furnace and all components of the heating electrothermal integrated in the same instrument body, and to achieve the flame and graphite furnace free conversion. \x0d\3, TH-AAS method. \x0d\ The method is characterized by integrated flame + built-in graphite furnace, free switching. One device can detect lead, zinc, copper, calcium, magnesium, iron and other elements in blood. The pre-treatment process of the sample is simple, with less sampling, less contamination, fast detection and good accuracy. Only need to add trace blood into the reagent, can be tested on the machine, the real realization of trace blood test lead, copper, zinc, calcium, magnesium, iron and other trace elements.