Analysis of trace elements and heavy metals in Chinese herbal medicine by AA-1800 atomic absorption spectrometry - Master's thesis - Dissertation

Analysis of Trace Elements and Heavy Metals in Chinese Herbal Medicine by AA-1800 Atomic Absorption Spectrometry

Key words: atomic absorption spectrometer; trace elements; heavy metals; Chinese herbal medicine; analysis instrument ; AA-1800 atomic absorption spectrometry (AAS), also known as atomic absorption spectrophotometry, based on ground state An instrumental analysis method for quantifying the measured element by the atomic vapor to be measured for the absorption intensity of the characteristic line of the element in the light source. It began in the mid-1950s and is mainly applicable to the quantification of trace and trace components in the sample. Analysis, its atomization methods are mainly flame, graphite furnace and hydride method. Atomic absorption spectroscopy has been rapidly developed in recent decades, and has been widely used in many fields so far. Its main advantages are: 1 selectivity Well, because the atoms of different elements have their own inherent energy levels, the gaseous ground state atoms of each element only absorb light of certain wavelengths. Moreover, the atomic absorption bandwidth is very narrow, and the coexisting elements have little interference with the elements to be measured, so Its selectivity is very high. In inorganic analysis, it is often necessary to separate the coexisting elements for measurement; 2 high sensitivity, flame atomic absorption method Sensitivity can reach 10_10g, and the absolute sensitivity of graphite furnace atomic absorption method can reach 10_10 ~ 10_14g, so it is suitable for quantitative analysis of trace and trace elements in samples; 3 wide range of analysis, many elements can be determined by atomic absorption spectrometry More than 70 kinds, can measure trace elements as well as trace or even trace elements, can measure metal elements, metal-like elements, indirectly determine some non-metallic elements, and indirectly determine organic matter, etc. Atomic absorption spectroscopy also has the advantages of simple operation, high analysis speed and high accuracy (flame method error <1%, graphite furnace method error 3% ~ 5%), and good precision (in the measurement of 曰 often low content, the precision is Advantages of 1% ~ 3%). Traditional Chinese medicine has a history of thousands of years in China and is a treasure of the Chinese nation. China has abundant medicinal plant resources, and its plants as Chinese herbal medicines contain macroscopic quantities such as potassium, phosphorus and nitrogen. In addition to elements, it also contains iron, boron, arsenic, manganese, copper and other trace elements. However, due to the long-term research on the effective chemical composition of traditional Chinese medicines, organic compounds have been neglected. In recent years, with the deepening of research on trace elements in traditional Chinese medicine, it has been found that the efficacy of some traditional Chinese medicines has a certain correlation with the content of trace elements and the content of some trace elements. Therefore, modern Chinese medicine has recognized Chinese medicine. Trace elements are one of the material basis for determining the four properties of traditional Chinese medicine, and also the core component of the active ingredients of traditional Chinese medicine. Therefore, quantitative analysis of trace elements contained in Chinese herbal medicines, to explore the relationship between the content of trace elements in Chinese herbal medicines and curative effect, to clarify Chinese herbal medicines The traditional pharmacology, the exploration of Chinese medicine preparation process and the identification of the quality of Chinese herbal medicines are of great significance. In addition, with the rapid development of China's industrialization process, heavy metal pollution caused by industrial, transportation and domestic waste is becoming more and more serious. The waste slag, waste water and waste gas are absorbed into plants after being discharged into the environment, resulting in an increase in the content of heavy metals in Chinese herbal medicines, which reduces the quality of Chinese herbal medicines and even brings hidden dangers of heavy metal poisoning to patients. The heavy metals present in Chinese herbal medicines generally include lead, mercury and cadmium. , copper, antimony, tin, chromium, nickel, iron, zinc, tungsten, etc., although arsenic is not In metal, but the source and hazard are similar to heavy metals, so it is often included. Different heavy metals act on different parts or systems of human body, and the symptoms of poisoning are different, and lead, cadmium, mercury, arsenic, etc. are currently Recognized as a heavy metal that is more harmful to the human body. Lead is harmful to the nervous system, digestive system and bone hematopoietic function; mercury poisoning seriously affects the central nervous system of the human body, which can weaken hearing, language out of control, limb paralysis, etc. Although copper Heavy metals such as iron and zinc are also essential trace elements in the human body, but they may still be highly toxic when they accumulate in the body to a certain amount or in a certain valence state. For example, a higher concentration of copper has a hemolysis effect. It can cause benign necrosis of liver and kidney. Therefore, the World Health Organization (WHO) clearly stipulates the baseline value of heavy metal absorption. In addition, many countries have clear limits on the content of heavy metals in imported Chinese herbal medicines and proprietary Chinese medicines. Study on the detection method of heavy metals in Chinese herbal medicines, and formulate the national standard method and limit control for the detection of heavy metal elements in Chinese herbal medicines Standards, it is of great practical significance for Chinese herbal medicines to go abroad and participate in the competition in the international pharmaceutical market. 1 Sample processing methods Almost all Chinese herbal medicines need to be pretreated to destroy the organic components and convert the components to be tested into inorganic compounds. After the preparation of the test solution suitable for atomic absorption spectrometry. For atomic absorption spectroscopy, the sample processing process is undoubtedly the main source of error in the trace element analysis of Chinese herbal medicine. Therefore, it is very important to choose the appropriate sample processing method. Sample processing methods include dry ashing, wet digestion, acid dissolution, and microwave digestion. For the indigestible Chinese herbal medicine, two digestion methods can be used to improve the digestion effect. For example, the literature 4 utilizes The combination of dry ashing and wet method determined the content of heavy metals such as lead, cadmium and copper in 15 commonly used proprietary Chinese medicines, which reduced the volatilization caused by dry ashing, and the blank value was less than wet. Method of digestion. Dry ashing method is the most traditional method. It uses equipment that is easy to popularize, no reagent pollution, but there are cumbersome steps and consumption. The length of the interval and the labor intensity of the analyst are insufficient. In addition, it has limitations on the elements of choice. The wet digestion method has wide applicability and is a commonly used digestion method in ordinary laboratories, but its blank value tends to be higher. The heating and digestion process of the open system is poor in safety. Some acids (such as perchloric acid) may explode during use. In addition, there may be harmful gases that may cause harm to human health during the digestion process. To overcome these Disadvantages, microwave digestion technology came into being, and gradually became a routine sample processing method in the past ten years, which has the advantages of fast heating rate, high efficiency, etc., because the closed container is used, the existence of the sample can be avoided. Or the loss caused by the overflow of volatile components formed during sample digestion. At the same time, it can reduce the amount of acid used to significantly reduce the blank value and ensure the accuracy of the determination results. For example, the literature H uses concentrated HNOg, H2 O2 microwave digestion and atomic absorption spectrometry were used to determine Fe, Cu, Zn, Mn, Mg and Ca in A. sinensis. The determination results were accurate and the recovery was between 90.00% and 101.33%. The method not only reduces the dissolution time, but also avoids the use of explosive perchloric acid, and is a fast and accurate method for detecting metal elements. Although microwave digestion has many advantages, it is more expensive instruments and consumables and cleaning difficulties. In addition, some applications have been limited. In addition, recently, nanomaterials have been used as adsorbents, and Cd, Pb, and grass fennel in pre-treated solutions of valerian and lettuce have been pre-enriched/separated by solid phase extraction. Cr and Fe in digestive juices such as chickpeas and cloves, and then the contents of these elements were determined by atomic absorption method, and satisfactory enrichment effects and precision and accuracy of the method were obtained, and the pretreatment steps were omitted. , Document 8] connected a solid pyrolysis device with an atomic absorption spectrometer to establish a rapid method for the determination of trace mercury in traditional Chinese medicine (Ganoderma Lucidum, Kudzu, Gastrodia), which has the advantage that the sample does not need to be digested to solid injection. The method was directly analyzed and determined. They were compared with the standard reference materials and compared with the analytical results of ICPIS. The results were satisfactory. 2 Determination of trace elements and heavy metals Analysis 2.1 Determination of trace elements in single-flavor Chinese medicine At present, atomic absorption spectrometry has become a mature instrumental analysis technique for the determination of trace elements in single-flavor Chinese medicine. Literature 9 uses HNO; -HCIO4 wet digestion, using atomic absorption spectrophotometry The content of trace elements iron, manganese and zinc in Bupleurum chinense L. was determined. The results showed that the content of metal elements in Bupleurum chinense by atomic absorption spectrophotometry was convenient and rapid, and the results were accurate. The content of elements in different parts of the same medicinal material It may be different. For example, the literature found that the content of trace elements in different medicinal parts of Angelica is quite different, the content of iron in the tail is higher, the content of copper in the corpus is higher, and the content of zinc in the homing is higher. The content of the body is relatively high. Therefore, these data provide a scientific basis for the clinical application of the three parts of the categorization, homing, and tailing. The literature [11] discusses the content of heavy metals and the correlation of trace elements in anti-aging Chinese herbal medicines. Sex, measured iron, calcium, zinc, magnesium, copper, lead, chromium, antimony and arsenic in eight traditional Chinese medicines such as Epimedium and Schisandra, and found a significant correlation between lead and magnesium. The contents of heavy metal elements such as lead and buckwheat in Radix Puerariae were determined by graphite furnace atomic absorption spectrophotometry. The contents of heavy metals in Danshen, American ginseng, Angelica sinensis and Radix Scutellariae were compared. The results showed that the Pb in Pueraria lobata was 4. 633 mg / Kg and Cd are 0. 225 mg/kg, which is indistinguishable from the traditional Chinese medicinal materials of salvia miltiorrhiza, American ginseng, white peony and astragalus with heavy metal content in the Chinese Pharmacopoeia. Since each element has different properties, it should be tested according to The element chooses the appropriate atomization method. The flame atomic absorption method is suitable for the determination of most elements, such as zinc, iron, copper, manganese, etc., and has good reproducibility and easy operation. However, its disadvantage is that it is only about 10%. The test solution is atomized and the atomization efficiency is low; the graphite furnace atomization device can improve the atomization efficiency and increase the sensitivity by 10 to 200 times. It is mainly for the alkali metal and some transition elements which are easily oxidized and easily dissociated; hydride atom The chemical method is aimed at some elements that are easy to form hydrides, such as mercury, arsenic, etc. As in the literature [13], different contents of copper, lead, arsenic, mercury and cadmium in Radix Pseudostellariae, Hawthorn and Chinese yam are established according to the different elemental characteristics. Determine the method by flame method to determine the content of copper, atomic absorption spectrometry atomic absorption spectrometry determination of single-flavor Chinese herbal medicine related reports are shown in Table 1. Table 1 atomic absorption spectrometry determination of trace elements and heavy metals in single Chinese medicine Table 1 Determination Of trace elements and heavy metals in single traditional Chinese medicine by AAS Chinese herbal medicines, the elements of the test, such as Houttuynia cordata, forsythia, plantain, Daqingye, Pulsatilla, etc. 20 kinds of Fe, Mn, Zn, Cu, Ni, Co, Ca, Mg, Cd, Pb, Cr [14] Boxing Fe, Mn, Zn, Cu [15] Ginger Fe, Mn, Zn, Cu, Ca, Mg [16] Hypericum perforatum Cd, Co, Pb [17] 12 kinds of As, Cr, Pb, Ni [18] birch leaves, dandelion roots, hawthorn flowers Ba, Cd, Cr, Cu, Fe, Ni, Pb, Zn [19] 2.2 Determination of Trace Element/Heavy Metal Content in Traditional Chinese Medicine Compound Generally, the proportion of trace elements in traditional Chinese medicine compound is obviously different from that of single Chinese medicine, but it has not been explained clearly from the perspective of various trace element ratios and chemical interactions of various drugs. The principle of the traditional Chinese medicine compound. However, the study on the trace elements in the Chinese herbal compound It provides an important experimental basis for elucidating these problems. The literature, such as 20], quantified the inorganic elements of Cu, Cr, Mg, Fe, Ba, Mn, Ca and Pb in 10 kinds of proprietary Chinese medicine solutions by flame atomic absorption spectrophotometer. The determination provides a certain basis for clinical rational drug selection. In the literature 21] the content of lead in the Erhua Sancao mixture was determined by atomic absorption spectrometry. The results showed that the lead content complies with relevant regulations. The method is simple, fast and reproducible. Good property, strong specificity and high sensitivity. Literature 22] The sample was treated by wet digestion, and the contents of trace elements Fe, Mn, Zn, Cu, Cd and Pb in Shuanghuanglian oral liquid were determined by flame atomic absorption spectrometry. Cu, Cd, Pb are not exceeded, can be safely taken. Table 2 lists the application examples of the determination of trace elements in traditional Chinese medicine by atomic absorption spectrometry. Comparing the trace elements contained in the same Chinese herbal medicine, it is helpful to clarify the traditional Chinese medicine. The relationship between trace elements and curative effect. 2)] Determination of 9 kinds of proprietary Chinese medicines such as Xiaoke Pill, Yuquan Pill, Thirst Lening, Jiangtangshu and Jiangtang IV for the treatment of diabetes by atomic absorption spectrometry In liquid Fe, Mn, Cd, Pb and other 12 kinds of trace elements. The results show that in addition to Cd, Pb, and other 10 elements in the traditional Chinese medicine for diabetes, the content of trace elements in the above-mentioned diabetic Chinese patent medicines is rich. The relationship with the drug efficacy provides valuable reference data. The literature [14] used ashing method to treat the sample, HNO3 dissolved the ash residue, and determined 20 kinds of heat-clearing and detoxifying Chinese herbal medicines such as Shegan and Pulsatilla by flame atomic absorption spectrometry. Eleven elements such as Ca, Mg, Mn, Cu, Cd, etc. The results show that these heat-clearing and detoxifying Chinese herbal medicines are rich in trace elements such as Ca, Mg, Fe, Zn, Mn and Cu which are beneficial to the human body. Table 2 Atomic Absorption Determination of trace elements/heavy metals in traditional Chinese medicines by spectrometry Table 2 Determination of trace elements or heavy metals in Chinese patent medicine by AAS 3 Speciation analysis of trace elements in Chinese herbal medicines In recent years, people have studied the relationship between trace elements and therapeutic effects in Chinese herbal medicines. It has been found that the activity of the same trace elements in different Chinese medicines is different, that is, the effect of trace elements of traditional Chinese medicine on the human body is often not determined by the total amount, but mainly The chemical forms in which they are located, including valence, complexation, etc. This is due to the fact that the bioavailability of trace elements and their physiological and toxicological biochemical behaviors are closely related to their chemical forms. Therefore, trace elements in Chinese herbal medicines In the study, the chemical speciation analysis of trace elements is of more significance. It can clarify the active constituents of Chinese herbal medicines at the molecular level and provide a theoretical basis for the study of the pharmacological mechanism of trace elements in Chinese herbal medicines. However, due to the lack of mature sample processing And morphological analysis methods, and currently there are few standard chemical substances in Chinese herbal medicines, which bring great difficulties to the chemical analysis of elements with low content of complex Chinese herbal medicines. Therefore, reports on the speciation analysis of trace elements in Chinese herbal medicines Not much, and the depth of research is not enough. At present, the morphological analysis of trace elements in Chinese herbal medicine is to separate the different forms by appropriate separation methods, and then select appropriate analytical methods according to different elements and their morphology. The dosage form is decoction and tincture, so so far reported more Study on the dissolution rate of metal elements in decoction. In China, the research on the speciation analysis of trace elements in traditional Chinese medicine began in the 1990s. The literature summarized the hierarchical pattern of trace element speciation in Chinese herbal decoction for the first time. It includes primary and secondary forms: 1 Primary morphological analysis, including determination of the type and content of trace elements in the crude drug, investigation of the leaching of trace elements in the decoction and separation of the particles from the soluble state by means of a filter; 2 secondary morphological analysis, including the distinction between various forms, such as particulate, colloidal and soluble, organic and inorganic, steady and unstable, and some oxidation states with variable valence elements, etc. In fact, at the molecular level, the specific structure of trace elements in Chinese herbal medicines (including metal compounds and metal complexes formed by combining proteins, amino acids, lipids, sugars, and alkaloids) and advanced morphological analysis of functions are studied. Important, this is because the ultimate goal of morphological analysis of trace elements in Chinese herbal medicine is to identify the specific form of trace elements and To reveal the active substance basis and pharmacological mechanism of traditional Chinese medicine, so as to provide a theoretical basis for the discovery and production of new drugs. So far, the most studied elements in the morphological analysis of trace elements in medicinal plants are Zn, Fe, Mn, Cu. Mg, Ca, As, Se, Hg, etc. 3.1 Primary morphological analysis of trace elements The main purpose of primary morphological analysis of trace elements in Chinese herbal medicines is to find out which elements and forms of Chinese herbal medicines are in use. Determination of the types and contents of trace elements in Chinese herbal extracts by certain separation and testing methods, so as to obtain the extraction rate, residual rate, particle adsorption rate and leaching ratio of these elements, which can quantitatively characterize some trace elements in Chinese herbal medicines. The extraction rate is directly related to the Chinese herbal medicine ingredients actually taken by the human body. It is the effect of the pharmacological or toxic components of Chinese herbal medicines. It is also an important basis for formulating the dosage or examining the toxicity. The leaching ratio of the elements refers to the elements in the soaking solution. Ratio of the content of the element to the content of the element in the immersion residue, which is the scale at which an element exerts its efficacy, and the immersion ratio is the most The element is often considered to be the most important element in the Chinese herbal medicine. Since the Chinese herbal decoction (ie, decoction) is a commonly used dosage form, the trace element component in the decoction is usually the component actually applied to the human body. Therefore, the study of the presence of trace elements in traditional Chinese medicine decoction has important reference value for exploring the true active ingredients and pharmacological effects of Chinese herbal medicine. At present, the most commonly used primary form analysis method for trace elements in Chinese herbal medicine is to use traditional boiling method for Chinese herbal medicine. The medium and trace elements are extracted, and the residue and the decoction are obtained by filtering with gauze, etc., and the soluble state and the suspended state in the decoction are separated by a microporous membrane, and then the content of the elements in the different components is determined by atomic absorption, for example. Literature M uses n-octanol-water partition system to simulate the distribution of traditional Chinese medicine decoction in human stomach and intestine. The determination of Zn, Fe, Mn, Cu, Mg, Ca in Angelica, Astragalus and Danggui Buxue Decoction by flame atomic absorption spectrometry. , Ni total content of 7 kinds of metal elements in the medicinal materials, as well as the water-soluble and alcohol-soluble content of each metal element in the decoction, and the compatibility and acidity of the water are discussed. The effect of metal element content in liquid. The experimental results show that the form of metal elements in traditional Chinese medicine is related to the composition of traditional Chinese medicine, the compatibility and the acidity of the target target (gastrointestinal), the compatibility and acidity of the metal elements in Chinese medicine and the decoction. The morphology of medium metal elements has a great influence. In the literature 31_34, a variety of Tibetan herbs produced in the Qinghai-Tibet Plateau were studied by atomic absorption spectrophotometry. The green velvet, Chuanmuxiang 62, rabbit ear grass 63, jellyfish were determined. The content of more than ten kinds of elements such as Cu, Fe, Mn, Ni, Se, etc. in the whole medicinal materials, water extracts and alcohol extracts of Tibetan rabbits such as snow rabbits and succulent plants, and the soluble elements in the aqueous extracts The content of water and dissolved state. Similarly, the distribution of trace elements in Tibetan medicine aqueous extracts in human stomach and intestine was simulated by n-octanol-water partitioning system. The primary form of trace elements in Tibetan medicine was analyzed. This paper discusses the effects of changes in human gastrointestinal acidity on the absorption of trace elements, and discusses the related effects of Tibetan medicines. This is of great help to further study the relationship between trace elements and Tibetan medicines and drug efficacy. ,文35]采Mn, Mg, K in bismuth were separated by different pore size filters, and their primary morphology was studied. They first filtered through a 0.45 μm filter to obtain a soluble state, and then used 0.22, 0.15, 6.6, 3.8 respectively. The nm membrane was separated step by step. Then the content of the elements in the filtrates was determined by flame atomic absorption spectrometry. Combined with the main organic components in the strontium, the compounds of the combination of metals and different organic compounds may be discussed from the molecular weight point of view. Morphology. It was found that the main complex of Mg and K in the decoction of sputum was larger than 0.22 or less than 3.8 nm. The Mn, Mg and K elements in strontium may be combined with steran to form a complex. Some of them may exist in an ionic state or in combination with a component with a small molecular weight. 3.2 Secondary morphological analysis of trace elements The secondary morphological analysis is to further analyze the soluble components of Chinese herbal extracts, and the commonly used analytical procedures. The Chinese medicine extract is first filtered with a filter of 0. 45 μm to obtain a soluble state in the extract, and then the soluble state is obtained by using a cation exchange resin, a macroporous adsorption resin and a chelating resin, respectively. Free and non-free, organic and inorganic, stable and unstable, and then analyze the different components by appropriate detection methods. For example, in the literature 30] extract the trace elements in Astragalus by traditional boiling method, The microporous membrane separates the soluble and suspended states in the extract, and the macroporous resin column separates the organic and inorganic states in the soluble state. The Cu, Zn, Fe in various forms are determined by flame atomic absorption spectrometry. Six kinds of elements, such as Mg, Ca and Cr. The results show that the ratio of organic and inorganic states of Cr is not much different in the soluble state, while Cu, Zn, Fe, Mg and Ca mainly exist in inorganic state, and their organic states only account for Inorganic state 3% ~ 4%. The literature [56] used a similar method to separate Cu, Zn, Mn, Fe, Mg, Ni in the decoction of Xiangqinglan into suspension and soluble, organic and inorganic states. And using the n-octanol-water partition system to simulate the distribution of these six metals in the human gastrointestinal tract, and their content, distribution and dissolution characteristics in different solvents were determined by flame atomic absorption spectrometry. Chemical form, thus establishing four methods for the separation and analysis of the above six metals. Using flame atoms The morphological distribution of bioactive trace elements Fe, Cu, Mn and Zn in Fufang Danshen Tablet decoction and artificial gastric acid extract was studied by absorption spectroscopy. The two extracts were separated by Oasis MHLB solid phase extraction cartridge. The inorganic and organic states of the above four elements; the stable and unstable states of the four elements were separated by D401 chelating resin; the organic binding state with tanshinic acid was separated by Amberlite XAD macroporous adsorption resin. The results showed that: Zn, The protein binding state of Cu is higher, and the copper is the main component of the polysaccharide. The content of iron in the organic binding state of tanshinic acid is the highest. 3. 3 Metal complex analysis Some trace elements or organic compounds have certain physiological characteristics. Activity, but it is also common for metals to have synergistic effects with organic compounds. Further studies have found that certain metal ions can change their original activities after forming complexes with natural products, and some have enhanced efficacy after forming complexes. Some even have new curative effects. In the traditional Chinese herbal preparations, metal ions are often boiled into the decoction, which can be organic with Chinese herbal medicine. Such as alkaloids, flavonoids, coumarins, hydrazine, organic acids and even proteins to form complexes. People have noticed that some organic components of Chinese herbal medicines enter the human body, the selectivity to target cells is poor, so the effect is not good Even with strong toxic side effects, when they form complexes with certain trace elements, they are easily combined with certain carriers due to changes in their molecular size, stereo configuration, charge distribution, and fat solubility. It changes the absorption, function and distribution in the body, increases their selectivity to target cells and receptors, thus improving the efficacy and reducing the side effects. For example, it has been found that baicalin forms a complex with metal ions such as Cu2+ and Zn2+. After the substance has a significant effect on the removal of superoxide radicals, inhibition of lipoxygenase and anti-inflammatory, antibacterial, antiviral, anti-allergic reactions, etc. In fact, some effective chemical components in Chinese herbal medicines are not only complexes. The form is present in Chinese herbal medicines and their preparations, and may also function in the human body in the form of complexes. Therefore, some people think that the effective chemical constituents of traditional Chinese medicine are mainly A complex composed of organic molecules and trace elements, which can better reflect the material basis of traditional Chinese medicines than pure organic molecules or pure trace elements. It is the effective chemical component of traditional Chinese medicine in the overall sense, and also represents the core of the active role of traditional Chinese medicine. In the past ten years, the research on the metal complexes of the active ingredients of natural medicines has achieved certain theoretical and practical results, and there are some review reports. In particular, some metal complexes of active ingredients of traditional Chinese medicines have been found to have After strong anti-tumor activity, in recent years, the research field of metal-based antitumor drugs based on active ingredients of traditional Chinese medicine has become a hot topic. However, the research on metal complexes of traditional Chinese medicines is not deep enough and systematic, and the mechanism is rarely discussed. The atomic absorption method has fewer applications in this field. At present, the study of metal complexes of active ingredients of Chinese herbal medicine is mostly concentrated on flavonoids, such as baicalin, rutin, etc., which is the core of flavonoids. The structure is closely related. In addition, there are some reports on the study of alkaloids, coumarins and terpenoids. The main metal elements studied are mainly Concentrated on elements such as copper, zinc, iron, aluminum and rare earth. For example, in Article 43], the organic components in Astragalus membranaceus were extracted by chemical extraction, and then the elemental copper in the corresponding extract was determined by graphite furnace atomic absorption spectrometry. It is distributed in different organic components, but especially in flavonoids (TFA) and polysaccharides (TPA), and copper has strong correlation with TFA and TPA. This result indicates that copper may form certain with TFA and TPA. Metal complexes or compounds, which provide important clues to the further discovery of metal complexes in Chinese herbal medicines. In addition, the literature &4] for various natural products of copper and lactones, hydrazine, flavonoids, polysaccharides, alkaloids The chemical structure and biological activity of the type complexes are reviewed. It is concluded that copper ions can form complexes with various types of natural products such as lactones, terpenoids, flavonoids, and alkaloids, and most of the complexes produced have More anti-tumor, anti-bacterial or anti-oxidant biological activity than the original natural product. In addition, the literature 45] has been used in five kinds of Chinese herbal medicines such as medmont, white fresh skin, nutmeg, acacia, and invertebrate The genus complexes were studied. The results showed that Zn, Cu and Mo were mainly in the form of metalloprotein in the tested Chinese herbal medicine, and the highest content in the insoluble phase. Secondly, it was in the form of water-soluble ions and distributed in the water-soluble phase. In the middle, the determination of the elements in the fat-soluble phase indicates that these elements rarely exist in the form of organic complexes. At the same time, they also analyzed the existence forms of toxic heavy metals in the five Chinese herbal medicines. The results show that Cd is mainly organic. The form of the complex exists, and the toxic form of Cd is relatively small, so the use of decoction does not generally cause cadmium poisoning. The Cr in the tested Chinese herbal medicine mainly exists in the form of inorganic ions, and the total content of Cr is higher. High, so it must be paid attention to when taking medicine, because adults can not exceed 20 -50^g of Cr safe intake per day. At the same time, it is found that Pb is mostly in the form of organic complexes in these tested Chinese herbal medicines, and the toxicity is high. However, the total lead concentration is relatively low. In addition, they also studied the existence of 14 rare earth elements in these five Chinese herbal medicines, and found that most of the rare earth elements may be gold. The form of protein exists. Although the development history of Chinese medicine coordination chemistry is not long, it has initially shown its important role in the research of Chinese herbal medicine. It is an important research field and development direction of modernization of traditional Chinese medicine, along with new separation technology and detection. The development of the means will continue to have new and important active Chinese medicine complexes discovered and applied. 4 Conclusion Atomic absorption spectroscopy is one of the most widely used quantitative analytical methods in the field of analytical chemistry. It has been widely used. There are at least dozens of related reports in China every year, which indicates that atomic absorption spectrometry is still one of the main methods for the analysis of trace elements in Chinese herbal medicine. Of course, it also has some shortcomings, and usually cannot be analyzed at the same time. Elements, the light source must be replaced to determine different elements, which is inconvenient for the analysis work, affecting the analysis speed and throughput. In addition, for some matrix complex sample analysis, there are still some interference problems to be solved; The sensitivity of the determination of insoluble elements is also unsatisfactory, and the linear range of the standard curve is not wide enough. After years of research and research by researchers, atomic absorption spectroscopy continues to develop and improve rapidly. For example, continuous light source atomic absorption spectrometer is a typical representative. The German Jena company developed the world's first product in 2004. Continuous light source atomic absorption spectrometer, in 2006, the company introduced a high-resolution flame / graphite furnace integrated continuous source atomic absorption spectrometer. It uses a high-energy xenon lamp to measure 67 metal elements in the periodic table. 2011 9 In the month, the graphite furnace continuous light source atomic absorption spectrometer contrAA 600 was introduced. It uses a high-focus short-arc xenon continuous light source to quickly analyze a variety of elements. It has a unique simultaneous background correction, real time measurement, no loss of sensitivity, and complete correction of the structural background. It can directly analyze the solids and other advantages. As far as atomic absorption spectroscopy itself is concerned, the development of new light sources to achieve multi-element simultaneous measurement still has a good development prospect. In addition, multi-waveguide and other technologies are also expected to achieve simultaneous determination of multiple elements. Greatly improve the analytical efficiency of atomic absorption methods. Due to the Chinese herbal medicine Some active ingredients are not free trace metal ions but some specific metal compounds. Therefore, only measuring the total amount of elements can not meet the new requirements of research and development of traditional Chinese medicine. Understand the existence of metal elements in traditional Chinese medicines, especially in practical use forms. Information such as morphology and valence is more important. It provides direct experimental evidence for elucidating the active constituents of Chinese herbal medicines and their pharmacological effects. However, since atomic absorption spectrometry can only be used to determine the total amount of elements in a sample, For morphological analysis, it must be combined with other separation techniques. Currently, the commonly used separation methods include chromatography, chemical extraction, ultrafiltration, etc. In addition, high-sensitivity detection instruments are used in conjunction with modern and efficient separation techniques. It will have great potential for the development of high-level morphological analysis of trace elements in Chinese herbal medicines (such as metal complex analysis). For example, liquid chromatography with high separation efficiency (including reversed-phase chromatography, ion-exchange chromatography, and size exclusion chromatography) Etch.) or capillary electrophoresis coupled with inductively coupled plasma mass spectrometry (ICPIS) or inductively coupled plasma optical emission spectroscopy (ICP-A) ES) and other detection methods combine to have the advantages of good separation effect, low sample consumption, fast speed, etc., and have the advantages of high sensitivity and wide linear range. We believe that these combined technologies will be able to analyze the trace elements in Chinese herbal medicines. Play an important role.