Evaluation of alcohol content and metal impurities in liquid dietary supplements by sHSS-GC-FID and GFAAS techniques

Despite efforts by many dietary supplements' manufactures to reduce or replace ethanol, many products containing ethanol in concentrations up to 70% are available on market. Furthermore, botanical dietary supplements can vary in metal content as a function of the environment, processing equipment and product containers. Therefore, the aim of study was to develop a new rapid and highly sensitive method for simultaneous determination of ethanol and its impurities in dietary supplements by sHSS-GC-FID technique. In addition, contamination with metals by GFAAS technique was evaluated. The proposed sHSS-GC-FID method was successfully applied for analysis of 93 samples containing various amounts of ethanol. It should be highlighted that the dramatic variation from manufacture's claims was found in even one third of products. Furthermore, high amounts of ethanol were found in several products especially designed for children and in one product labeled as “alcohol-free”. Metal impurities were below the limits established by USP.