Sample Preparation and Analysis of Dietary Supplements Using Sequential Microwave Digestion

Introduction

Growing consumer demand placed on health and nutrition has led to a plethora of dietary supplements available in the consumer market. The USFDA (United States Food and Drug Administration) defines these dietary supplements as items different than consumed foods with intent to supplement the diet through either vitamins, minerals, botanicals and herbs, botanical compounds, amino acids, or live microbials. Supplements are produced in varied forms for ease of ingestion including gel capsules, dissolvable, gummies, and powders. Dietary supplements are gaining significant traction with consumers, with approximately 60% of Americans using some sort of supplement from the over 50,000 available.

As with all ingested foods, heavy metals and elemental impurities are a cause for concern due to their negative impacts on human health. Elemental impurities come from a variety of sources during the production of dietary supplements, occurring either from the raw materials or inadvertent introduction during manufacturing. Under the USFDA Food, Drug, and Cosmetic Act, many criteria are used for regulating dietary supplements, including prohibition of adulterated or misbranded products, as well as, elemental impurities. It is of the utmost importance to ensure consumer safety by analyzing and monitoring the elemental levels present in dietary supplements.

In this study, we utilized the BLADE sequential microwave digestion system to digest different forms of multivitamins, dissolvable tablets, and a fish oil capsule. Samples were chosen to encapsulate a large range of capsule materials, as well as precursor materials.