Specific discrimination of zinc and manganese ions by label free dual emissive carbon dots by ratio-metric mode

• Published in: Talanta (Oxford) Vol. 260; p. 124627
• Main Authors: Li, Haimin, Huang, Xinyu, Zhang, Fengxian, Luo, Xueting, Yu, Wenqian, Li, Cao, Jiang, Bingbing, Qiu, Zhenpeng, Xu, Ziqiang
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.08.2023
• Subjects: Carbon dots; Excellent sensitivity; Manganese ions; Ratio-metric sensing; Zinc ions; Carbon dots; Zinc ions; Excellent sensitivity; Manganese ions; Ratio-metric sensing
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2023.124627

Due to the worldwide ecological and environmental issues induced by heavy metal pollution, including zinc and manganese, the ratio-metric discrimination of Zn2+ and Mn2+ based on CDs is urgently required. In this work, reduced CDs (re-CDs) with the intrinsic dual emissive peaks are obtained, and specific discrimination of Zn2+ and Mn2+ is realized by re-CDs with ratio-metric mode. With the addition of Zn2+, the fluorescent (FL) intensity at 650 nm increases obviously, while that at 680 nm progressively decreases. However, the presence of Mn2+ would induce the quenching of FL intensity at 680 nm while that at 650 nm remains constant. Then the Zn2+ and Mn2+ can be separately determined with the ratio of FL intensity at 650 nm to that at 680 mm (F650/F680). Under optimal conditions, the limit of detection (LOD) of Zn2+ is determined to be 9.09 nmol/L, and that for Mn2+ is estimated to be 0.93 nmol/L, which is much lower than previously reported work and standard level of Zn2+ and Mn2+ permitted in drinking water by WHO. Moreover, the specific recognition of Mn2+ and Zn2+ can be realized via the addition of different masking agents (ethylenediamine for Zn2+ and triethanolamine for Mn2+). Furthermore, our results reveal that the structural changes from –NH–CO to –NC–OH induced by Zn2+ contribute to the shift of FL peak from 680 to 650 nm while both static and dynamic quenching processes are involved in the detection of Mn2+. The ratio-metric probe was successfully applied to Zn2+ and Mn2+ determination in human serum samples and Sandy Lake water. [Display omitted] •The Zn2+ and Mn2+ is separately detected by intrinsic dual emissive CDs.•Great detection performance can be realized, in the aspects of lower LOD.•The specific recognition of Zn2+ and Mn2+ with ratio-metric mode has been realized.