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A carbazole-based fluorescent probe was synthesized and found to fluoresce (λem,max = 440 nm) in the presence of hypochlorite. Guided by a series of control experiments and kinetics studies, protocols for using the sensor to measure the concentration of hypochlorite under a range of conditions were established. The synthesized probe is highly selective for hypochlorite in the presence of interfering strong oxidants including dichromates (Cr2O72−). The probe was also used to quantify the presence of the ClO− oxidant in various sources of water conveniently. The underlying mechanism of the sensor was elucidated by NMR, HRMS, and cyclic voltammetry and further confirmed by DFT calculations to proceed through a series of tandem proton and electron transfer processes. [ABSTRACT FROM AUTHOR]

A novel carbazole-based probe was synthesized and found to exhibit fluorescence upon introduction to potassium permanganate in aqueous media. Guided by a series of experimental studies and DFT calculations, the underlying mechanism is proposed to proceed through a series of tandem proton and electron transfer processes. [ABSTRACT FROM AUTHOR]

Gentamicin is a broad spectrum antibiotic employed for the cure of infections caused by both Gram-positive and Gram-negative bacteria. It is eliminated through urine in the unmetabolized and microbiologically active form, leading to the emergence of gentamicin-resistant bacteriocoenosis. Green synthesis of methyl gallate conjugated silver nanoparticles (MG–AgNPs) is reported in this study. The synthesized MG–AgNPs were found to be stable at high temperature, in the pH range 4 to 8, and with up to 100 mM NaCl concentration in the solution. Further, the synthesized MG–AgNPs were employed as a selective and sensitive probe for the detection of gentamicin. The proposed colorimetric aggregation sensor significantly detected gentamicin over a wide range of concentrations in the presence of other interfering drugs and metal ions. UV-visible spectroscopy, FTIR, and atomic force microscopy were employed to confirm the sensing phenomenon. The binding ratio of MG–AgNPs with gentamicin was found to be equimolar. The limit of detection and quantification were found to be 0.29 μM and 1 μM, respectively, in the concentration range of 1–100 μM. The proposed sensor significantly detects gentamicin in environmental waters, human blood plasma, serum, and urine. [ABSTRACT FROM AUTHOR]