Selective and sensitive chemosensor for lead ions using fluorescent carbon dots prepared from chocolate by one-step hydrothermal method

Microalgae biochar-derived carbon dots and their application in heavy metal sensing in aqueous systems

“…Compared with the methods previously reported for the primary production of microalgae Cdots, the method reported in this article not only provides a value-added product from industrial waste, but is also a simpler and faster approach using a two-step method with 4 h of processing time to produce MAB-Cdots. The optical properties of the MAB-Cdots, such as photobleaching resistance, pH stability and negative zeta potential, support their use as a detection probe for heavy metal ions (Gu et al, 2016;Liu et al, 2016b;Ye et al, 2017). Photobleaching is the alteration of a fluorophore that makes it permanently unable to fluoresce.…”

“…The principle for heavy metal detection using Cdots is fluorescence quenching, where the metal ions interact with the Cdots fluorophores groups 74 and reduce their fluorescence. The quenching effect is dependent on the metal ion-Cdot 75 interaction, which is different for each type of Cdot and metal ion (Gogoi et al, 2015;Gu et 76 al., 2016;Liu et al, 2016b;Song et al, 2015;Tiong et al, 2015;Ye et al, 2017;Zhang et al, 77 2015). For instance, chicken egg white Cdots were only quenched by Fe 3+ ions (Zhang et al, 2015) while DNA-derived Cdots were quenched by both Hg 2+ (20 μM) and Ag + (20 μM) ions (Song et al, 2015).…”

“…Cdots were quenched by Fe 3+ and Cu 2+ (Ye et al, 2017). Chocolate Cdots were quenched by Pb 2+ with a linear relationship between 0 and 2 μM (Liu et al, 2016b). Clearly, differences in the Cdot production process and input material influence the chemical structure and sensing capabilities of the diverse array of Cdots.…”

Biogreen Synthesis of Carbon Dots for Biotechnology and Nanomedicine Applications

“…Many research groups have also developed hydrothermal syntheses using green precursors such as beverages [ 33 , 34 ], fruit extract [ 35 , 36 ], food products [ 37 – 39 ], and biomass [ 40 , 41 ]. Sahu et al [ 42 ] reported a one-step hydrothermal treatment of orange juice to prepare highly luminescent CDs.…”

Carbon Dots: A Mystic Star in the World of Nanoscience

“…Enhanced photoluminescent property has been explained by doping of heteroatom that altered electron density in the cyclic structure of CDs (Figure 16(b)) [71] and multiphoton PL mechanism followed by anti-Stoke transitions (Figure 16(c) [73], pesticides [74], antibiotics [75], preservatives [76], and nonbiodegradable chemicals over a certain permissible limit in food staff [77]. CD-based PL quenching sensors are successfully employed for ultrasensitive detections of heavy and highly poisonous metal ions like Hg 2+ (Figure 17(a)) [73,78], Cr 6+ [79], Pb 2+ [80], Cu 2+ [81], Al 3+ [82], and Co 2+ [83]. In most cases, linear relationships between quenching of PL intensity of CDs and concentration of metal ion present in samples have been observed [84].…”