Determination of 10-hydroxy-2-decenoic acid and free amino acids in royal jelly supplements with purpose-made capillary electrophoresis coupled with contactless conductivity detection

Abstract

This study reported a simple and inexpensive method for determination of 10-hydroxy-2-decenoic acid (10-HDA) and free amino acids in different royal jelly based dietary supplement samples using a purpose-made dual-channeled capillary electrophoresis (CE) system with capacitively coupled contactless conductivity detection (C4D). The objective of the work is to propose a tool for food / quality control activities that can be realizable even with a modest infrastructure. 10-HDA and free amino acids were analyzed using the background electrolyte (BGE) solutions composed of 20 mM Tris(hydroxymethyl)aminomethane adjusted to pH8.5 with acetic acid and of 2 M lactic acid, respectively. The best achieved detection limit for 10-HDA was 0.039 mg/g and those for free amino acids were in ranged of 0.039–0.090 mg/g using the developed CE-C4D methods. Good agreement between results obtained from CE-C4D and those with the standard confirmation methods (HPLC-PDA) was achieved, with the result deviation for the two pairs of data being less than 5 % for 10-HDA and 16 % for free amino acids.