Switchable fluorescence of MoS2 quantum dots: a multifunctional probe for sensing of chromium(VI), ascorbic acid, and alkaline phosphatase activity

Unique photoluminescence response of MoS2 quantum dots over a wide range of As (III) in aqueous media

“…We observed that Fe (II) and Cu (II) had a quenching effect on the fluorescence of bare MoS 2 QDs, while we observed clear PL enhancement in the case of As (III) with MoS 2 QDs (figure 10). The quenching effect of Fe-ions on bare and functionalized MoS 2 QDs and copper ions on functionalized MoS 2 QDs fluorescence are already reported [29,37,38,42,32]. The response of these two other metal ions on the fluorescence of our MoS 2 QDs was consistent with the literature.…”

“…To the best of our knowledge, there is only one report on label-free detection of Fe (III) using bare MoS 2 QDs, but a concentration-dependent quenching in fluorescence intensity was observed, and not an enhancement [32]. Several other fluorescence quenching results are also on records using functionalized MoS 2 QDs to detect hypochlorite disinfectant [33], nitro-explosives [34,35], pesticide [36], metal ions such as Fe (III), Cr (VI), Cu (II), Au (III), Pb (II), and Hg (II) [29,[37][38][39][40][41].…”

Development of an “on-off-on” fluoroprobe utilizing an anthrylimidazole-based fluorescent ionic liquid for sensitive Cr(VI) and ascorbic acid detection

“…Based on S/N = 3 (N is estimated according to the standard deviation (SD) obtained from the blank sample, N=SD = 2.9 × 10 −3 , n = 10), the limit of detection (LOD) of the as-constructed fluorescent detection was calculated to be 9 nM ( Araujo, 2009 ). As listed in Table 1 , the LOD (9 nM) by this fluorescence sensor is substantially lower than those (0.021–1.5 μM) by the fluorescence detection based on PNCQDs, S, N-CDs, Si-CQDs, MoS 2 QDs, SiQDs, SQDs, and g-C 3 N 4 NSs ( Duan et al, 2020 ; Gong et al, 2017 ; Hu, Zhang, Gan, Yin, & Fu, 2018 ; Ji et al, 2021 ; Liu et al, 2019 ; Rong et al, 2015 ; Tan et al, 2021 ; Xu et al, 2019 ), while it is comparable in contrast to those by N-CDs (5.0 nM) (Zhang et al, 2018) and GQDs (3.7 nM) ( Huang et al, 2015 ). Significantly, the linear range (0.03–300 μM) of the AI-FIL based fluorescent detection for Cr(VI) is much wider than the previous methods ( Duan et al, 2020 ; Gong et al, 2017 ; Hu et al, 2018 ; Ji et al, 2021 ; Liu et al, 2019 ; Rong et al, 2015 ; Tan et al, 2021 ; Xu et al, 2019 ) and is comparable with those by N-CDs and GQDs (Zhang et al, 2018; Huang et al, 2015 ).…”

“…As listed in Table 1 , the LOD (9 nM) by this fluorescence sensor is substantially lower than those (0.021–1.5 μM) by the fluorescence detection based on PNCQDs, S, N-CDs, Si-CQDs, MoS 2 QDs, SiQDs, SQDs, and g-C 3 N 4 NSs ( Duan et al, 2020 ; Gong et al, 2017 ; Hu, Zhang, Gan, Yin, & Fu, 2018 ; Ji et al, 2021 ; Liu et al, 2019 ; Rong et al, 2015 ; Tan et al, 2021 ; Xu et al, 2019 ), while it is comparable in contrast to those by N-CDs (5.0 nM) (Zhang et al, 2018) and GQDs (3.7 nM) ( Huang et al, 2015 ). Significantly, the linear range (0.03–300 μM) of the AI-FIL based fluorescent detection for Cr(VI) is much wider than the previous methods ( Duan et al, 2020 ; Gong et al, 2017 ; Hu et al, 2018 ; Ji et al, 2021 ; Liu et al, 2019 ; Rong et al, 2015 ; Tan et al, 2021 ; Xu et al, 2019 ) and is comparable with those by N-CDs and GQDs (Zhang et al, 2018; Huang et al, 2015 ). The threshold limit of Cr(VI) in groundwater stipulated by WHO was 1.9 μM, which suggested that the AI-FIL-based fluorescent detection was sensitive enough for trace-level Cr(VI) detection in environmental waters ( Hu et al, 2018 ).…”

Infinite Coordination Polymer Nanoparticles Used for Fluorescence Turn-On Sensing of Ascorbic Acid

“…Therefore, it is significant to develop a sensitive AA assay to monitor its levels. So far, a wide range of analytic assays have been exploited for AA determination, where the fluorescence assay has attracted great attention due to its inherent advantages such as simplicity, high sensitivity, and rapid response. − However, fluorescent nanomaterials mostly utilized in the fluorescence AA assay are carbon dots, , semiconductor quantum dots, , and metal–organic frameworks, , which need complicated preparation and are time-consuming. In addition, many principles for detecting AA are indirect, relying on AA consuming their fluorescence quencher to make the signal recover. , This inconvenience, as well as susceptibility to interference, hinders the development of its practical application.…”