Rapid Determination of Calcium, Iron, and Zinc in Gluconate Oral Solutions by Solution Cathode Glow Discharge – Atomic Emission Spectroscopy (SCGD-AES)

A novel solution cathode glow discharge atomic emission spectroscopy (SCGD-AES) system coupled with simplified sample preparation was developed for determining Ca, Fe, and Zn in gluconate oral solution. The preparation of the oral solution only involves diluting 1 g of the sample 100-fold and acidification with HNO3 to a concentration of 0.1 mol L−1. The preparation of each solution requires less than 5 min. Five oral solutions containing Ca, Fe, and Zn were analyzed. The results indicate that the optimal parameters are HNO3 of pH 1.0 as the electrolyte, a sample flow rate of 2.05 mL min−1, and a discharge current of 65 mA. The detection limits (DLs) of Ca, Fe, and Zn were 58.64, 64.29, and 15.92 µg L−1. The analyses by SCGD-AES for Ca, Fe, and Zn using direct dilution are in agreement with the values by ICP-OES and SCGD-AES with digestion. A t-test was conducted on the oral liquid samples, revealing that the majority of the obtained p-values exceeded .05. In addition, SCGD-AES reduces the time, energy, and quantity of concentrated HNO3 compared with previous studies, and the measurement time of each oral liquid sample was less than 2 min. These findings demonstrate the use of SCGD-AES as an expedited and dependable method for the determination of trace elements in health food products.