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

Atomic absorption spectrometry (AAS), also known as atomic absorption spectroscopy, is a powerful analytical technique used to determine the concentration of trace elements and heavy metals in various samples, including traditional Chinese herbal medicines. This method relies on the principle that ground-state atoms absorb specific wavelengths of light emitted from a light source. The intensity of this absorption is proportional to the concentration of the element being analyzed. AAS has been widely applied in the field of analytical chemistry for decades due to its high sensitivity, selectivity, and accuracy. It is particularly useful for analyzing trace elements, which are present in very small quantities in samples. There are several atomization techniques used in AAS, such as flame atomization, graphite furnace atomization, and hydride generation. Each method has its own advantages and is suitable for different types of elements and sample matrices. In the context of traditional Chinese medicine (TCM), the analysis of trace elements and heavy metals is crucial for ensuring the safety and efficacy of herbal products. TCM herbs often contain a variety of elements, both essential and potentially harmful. For instance, they may contain iron, zinc, copper, and other beneficial elements, but they can also be contaminated with heavy metals like lead, mercury, and cadmium. These contaminants can originate from environmental pollution or improper processing methods. The presence of heavy metals in TCM can pose serious health risks if not properly controlled. Therefore, it is essential to develop reliable analytical methods to detect and quantify these elements. AAS offers a robust solution for this purpose. It allows for the precise determination of metal concentrations, helping to ensure that TCM products meet safety standards. Sample preparation is a critical step in AAS analysis. Common methods include dry ashing, wet digestion, and microwave digestion. Each method has its own advantages and limitations, and the choice of method depends on the type of sample and the elements of interest. For example, microwave digestion is often preferred for its efficiency and ability to minimize sample loss. In addition to elemental analysis, AAS can also be used for speciation studies, which involve determining the chemical forms of elements in a sample. This is particularly important in TCM, where the bioavailability and toxicity of elements can vary depending on their chemical form. For instance, some heavy metals may be more toxic when present in certain oxidation states or bound to organic compounds. Overall, atomic absorption spectrometry plays a vital role in the analysis of trace elements and heavy metals in traditional Chinese herbal medicines. Its accuracy, sensitivity, and versatility make it an indispensable tool in ensuring the quality and safety of TCM products. As research in this area continues to advance, AAS will remain a key technique for understanding the complex composition of TCM and its potential health effects.