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Present work reported a novel nanozyme g-C 3 N 4 @Cu, N-CDs with excellent peroxidase-like activity obtained by loading Cu and N co-doped carbon dots on g-C 3 N 4 (graphitic carbon nitride). g-C 3 N 4 @Cu, N-CDs can catalyze H 2 O 2 to generate hydroxyl radical •OH, which oxidizes o -phenylenediamine to 2,3-diaminophenazine, which emits orange fluorescence under ultraviolet light irradiation. The experimental results confirmed that 1,4-benzenedithiol (BDT) could inhibit the peroxidase-like activity of g-C 3 N 4 @Cu, N-CDs. Based the principle above, a colorimetric-fluorescence dual-mode sensor for rapidly sensing of BDT was creatively constructed with assisting of a smartphone. The sensor showed excellent linearity over ranges of 0.75–132 μM and 0.33–60.0 μM with detection limits of 0.32 μM and 0.25 μM for colorimetric and fluorescence detection, respectively. Moreover, a smartphone-assisted colorimetric array sensor was constructed to distinguish six sulfur-containing compounds according to the difference in the degree of inhibition of nanozyme activity by different sulfur-containing compounds. The array sensor could distinguish sulfur-containing compounds at low concentration as low as 0.4 μM. The results validated that the designed sensor was a convenient and fast platform, which could be utilized as a reliably portable tool for the efficient and accurate detection of BDT and the discrimination of multiple sulfur compounds in real water samples. [Display omitted] • g-C 3 N 4 @ Cu, N-CDs were prepared by facile and economic method. • g-C 3 N 4 @ Cu, N-CDs exhibited strong peroxidase-like activity. • Smartphone-assisted sensor for sensitive detection of benzenedithiol was established. • Designed smartphone-assisted array sensor discriminated sulfur-containing compounds. [ABSTRACT FROM AUTHOR]

In this work, a sensitive fluorescent sensor toward p-nitrophenol (4-NP) integrating magnetic molecularly imprinted materials and carbon dots (CDs) was proposed. Magnetic material and CDs derived from K 3 [Fe(CN) 6 ] and glucose were simultaneously obtained through simple one-step hydrothermal process. Introducing of molecularly imprinted materials based magnetic solid phase extraction (MSPE) endowed the constructed fluorescent sensor with higher sensitivity and selectivity. The significant factors affecting the sensitivity of the sensor toward 4-NP were optimized. Good linearity was obtained between fluorescent intensity of CDs and different concentration of 4-NP from 0.08 to 62.5 μg L−1. The sensitivity of constructed sensor was very low with detection limit of 0.02 μg L−1. Reliable applicability was also proved by the well-pleasing recoveries of 94.2–97.8% with different spiked concentrations of 4-NP in real environmental waters. [Display omitted] • MMIPs based MSPE was integrated with CDs for constructing FL sensor toward 4-NP. • CDs and magnetic core were simultaneously prepared via one step hydrothermal process. • The constructed sensor exhibited good sensitivity and reliability for detecting 4-NP. [ABSTRACT FROM AUTHOR]