Establishment and validation of an optimized analytical method for ferrous gluconic acid in health functional foods using HPLC-ELSD and LC/MS

Abstract

Ferrous gluconate has been used in Korea, the United States, Japan, and the European Union to control the acidity in foods. We optimized an analytical method to determine the levels of ferrous gluconate in foods by a high-performance liquid chromatography-evaporative light scattering detector (HPLC-ELSD) and an ultra-performance liquid chromatography-mass spectrometry (UPLC-MS). The linearity of the developed analysis method using HPLC was excellent with a coefficient of determination (R2) of 0.999 obtained from calibration curve, and limits of detection and quantitation were 12.8 μg/mL and 38.9 μg/mL, respectively. In intra-day and inter-day analysis, the accuracy was 95.6~101.5% and 98.6~103.1%, respectively, and the precision was 1.5~2.6% and 0.7~2.9%, respectively. The measurement uncertainty of analyzing the health functional food samples was within 3%, and the verification results of all analytical methods met the standards of the European Commission (EC). UPLC-MS was also used to confirm ferrous gluconate. As a result, the field applicability of the ferrous gluconate analytical method developed in this study was confirmed.