(M1030-05-30) Analysis of Amino Acid Content in Commercially Available Supplements

Purpose: With the increase popularity of energy supplements, there is a need to monitor amino acid content in these products to ensure product safety. However, these products are controlled by varying regulatory agencies from country to country, each with different safety requirements [1,2].  While the medicinal properties of amino acids in supplements is unknown, the label claim of these supplements is assumed to be accurate. To quantify amino acids in these supplements, pre-column derivatization methods are often of value to minimize the interference of other components present in the formulation that may impact quantitation.

Methods: Several energy supplements were purchased and tested to quantify the amino acid content. For amino acid analysis derivatization was performed using 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC), followed by HPLC/UHPLC separation of the derivatives with reversed-phase liquid chromatography. Results were compared to the label claim of the products, including two powdered drink mix supplements and one amino acid supplement tablet. Any interfering peaks were identified through mass spectrometry (MS) and adjustments were made to allow for quantitation of all amino acids in the supplements.

Results: The results show the ability to reliably quantify amino acids in energy supplements. Initial method conditions were used to quantify a majority of amino acids, however, co-elution of citrulline and glutamic acid was identified by mass spectrometry. Subsequently, method conditions were altered to allow for quantitation of all the amino acids in two analyses. Based on the results, the weight of total amino acids was calculated and compared to the label claim. The results show (Table) agreement within 10% of the amino acid content to the label claim.

Conclusion: Analysis of amino acids in food and supplements is critical to ensure product safety and accuracy of the product’s label claim. While there are a range of amino acids, not all components may be separated under standard conditions. In this example, to facilitate method development, existing methodologies can be scaled and further optimized to create a robust method for the analysis of a wide range of amino acids. The results demonstrate the ability to quantify amino acid content in numerous energy supplements.

References: 1. Miro Smriga, International Regulations on Amino Acid Use in Foods and Supplements and Recommendations to Control Their
Safety Based on Purity and Quality, Journal of Nutrition; 150:2602S–2605S, 2020.

3. Ashley Roberts, The Safety and Regulatory Process for Amino Acids in Europe and the United States, Journal of Nutrition;
146(Suppl):2635S–2642S, 2016.

Figure 1. Supplement Sample Chromatograms



Table 1. Amino Acid Supplement Sample Results



Table 2. Amino Acid Supplement Sample Label Claim Results