In this study, carbon dots (CDs) that exhibit bright-blue fluorescence were hydrothermally synthesized from Nigella sativa seeds and employed for selective and quantitative detection of tetracycline (TC) and l-lysine (L-Lys). Specifically, TC addition led to quenching of CDs’ fluorescence intensity, while the enhanced fluorescence was spotted in the presence of L-Lys. CD quenching was attributed to both dynamic and static mechanisms, which is different from earlier-reported studies. In contrast, the introduction of L-Lys supported the emergence of hydrogen bonds between CDs and L-Lys, and consequently resulted in an increase in photoluminescence (PL) intensity. PL quenching was linearly correlated with TC concentration ranged from 0.01 to 40 μM with 14 nM detection limit. A linear correlation was observed for L-Lys in the concentration range of 0–500 μM and displayed a limit of detection of 453 nM. CDs showed TC detection in the range of 95.2–102.5% in tap water, river water, urine, and powdered milk. Likewise, CDs have been successfully utilized for detecting L-Lys in serum samples with a recovery range of 98.9–100.3%. The study describes the use of a dual sensing strategy for TC and L-Lys using green synthesized CDs. This study will provide an in-depth insight into the mechanism of TC and L-Lys detection by CDs, which will help to understand the role of different nanoparticles in sensing applications.

在这项研究中，碳的点（CDS），其显示出明亮的蓝色荧光水热合成自果黑种草种子并用于选择性和四环素的定量检测（TC）和升-赖氨酸（L-赖氨酸）。具体来说，添加TC会导致CD的荧光强度猝灭，而在L-Lys的存在下会发现增强的荧光。CD猝灭归因于动态和静态机制，这与先前报道的研究不同。相反，L-Lys的引入支持了CD和L-Lys之间氢键的出现，因此导致了光致发光（PL）强度的增加。PL淬灭与TC浓度范围为0.01至40μM（检测限为14 nM）线性相关。在0-500μM的浓度范围内观察到L-Lys的线性相关性，检测限为453 nM。CD显示自来水，河水，尿液和奶粉中的TC检出率为95.2–102.5％。同样 CD已成功用于检测血清样品中的L-Lys，回收率98.9–100.3％。这项研究描述了使用绿色合成CD对TC和L-Lys采用双重传感策略的方法。这项研究将提供对CD中TC和L-Lys检测机制的深入了解，这将有助于了解不同纳米颗粒在传感应用中的作用。