酸化モリブデン微粒子の表面増強フォトクロミック現象を利用したα-アミノ酸のラベルフリー定量法の開発

抄録

Due to the biological importance of α-amino acids and their derivatives, the development of novel colorimetric probes for these molecules has been an active research area in recent years. In this study, surface-enhanced photochromic phenomena by various α-amino acids (L-aspartic acid [Asp], L-leucine [Leu], and L-lysine [Lys]) adsorbed on molybdenum(VI) oxide (MoO₃) nanoparticles in an aqueous system were investigated by means of UV-vis absorption spectrometry. No derivatization of α-amino acids is required, and eventually highly accurate determinations are obtained from the UV-induced MoO₃ photochromic coloration. Under optimal conditions in this system, limit of quantitation (LOQ) values of 3.45 × 10⁻⁶, 2.08 × 10⁻⁶, and 1.53 × 10⁻⁶ mol dm⁻³ for Asp, Leu, and Lys, respectively, were achieved at pH 2. During UV irradiation, the detection process could be visually observed by naked eyes. A simple and unique approach to explore sensitive "label-free" colorimetric sensing toward α-amino acids is proposed.