抄録
Aspartame is a widely used artificial sweetener. For quality control purposes, it is necessary to quantify the impurities l-aspartyl-
d-phenylalanine methyl ester (l, d-APM) and 5-benzyl-3,6-dioxo-2-piperazine acetic acid (DKP). However, the sale of l, d-APM
standards has been temporarily suspended in Japan, leading to significant analytical challenges for the conventional HPLC method.
Additionally, a method that can simultaneously quantify aspartame, l, d-APM, and DKP to improve analytical efficiency is required.
In this study, we developed a method for the simultaneous analysis of aspartame, l, d-APM, and DKP using the relative molar
sensitivity (RMS) based on 1H-quantitative nuclear magnetic resonance (1H-qNMR) spectroscopy. Standard solutions prepared based
on the accurate purity of each compound determined by 1H-qNMR were analyzed by HPLC, and the RMS values for aspartame were
calculated from the slope ratio of the calibration curve. In method validation using samples spiked with aspartame, no statistically
significant differences were observed between the RMS method and the conventional absolute calibration method, demonstrating
excellent precision. The proposed method enables reliable simultaneous quantification without the use of challenging to obtain
quantitative standards while maintaining compatibility with existing regulatory HPLC conditions and improving analytical efficiency.
Furthermore, it could significantly improve the quality control of aspartame.
