Analysis of nutraceuticals for toxic metals: Development and validation of sample preparation method.

摘要

With increasing numbers of health-conscious consumers purchasing nutraceutical supplements, total sales in the nutrition industry have soared to over {dollar}200 billion in 2006.1 Approximately {dollar}50 billion of this was spent in the United States on functional foods and supplements, which are categorized as nutraceuticals and perceived to afford health benefits to the consumer. It is important to assess the safety of these nutraceutical products, with specific regards to toxic metals, including arsenic, cadmium, lead, and mercury. Because species of these metals may be more toxic than others, they can have hazardous health effects if ingested in excess quantities. Nutraceutical products can also vary by manufacturer, even if they contain the same active ingredient, and the plant ingredients used in manufacturing can be contaminated by pesticides or the soil in which they are cultivated.2; For many years, nutraceutical products fell under the category of "food" and, as such, they were not subject to strict restrictions, such as those established for "drugs." After the establishment of the Dietary Supplement Health and Education Act, which defined a dietary supplement, the U.S. Food and Drug Administration was able to set forth guidelines to establish good manufacturing practices (GMPs) for the production dietary or nutraceutical supplements. Though not focused directly on nutraceuticals, the State of California also enacted Proposition 65, which establishes levels of toxic elements or compounds that must not be exceeded on a daily basis.; The work described in this thesis focuses on the development of a sample preparation method for nutraceutical products, specifically ethanolic tinctures and glycerin-based matrices, and analysis of these products by inductively coupled plasma atomic emission spectrometry (ICP-AES) for toxic metal content. This method was developed by utilizing microwave digestion, which allows high temperatures and pressures for complete digestion of difficult sample types. A method was then established using an ICP-AES instrument that allowed simple and fast analysis through the generation of calibration functions for each toxic metal. Botanical standard reference materials (SRMs) of Ephedra sinica stapf and Gingko biloba were analyzed for arsenic, cadmium, lead, and mercury to assess the validity of the developed sample preparation method.