A Novel Fluorescent Sensor for the Sensitive Detection of Mercury

AbstractMercury pollution is a widespread danger to human health and environment. To developed a effective method for mercury detecting is in high demand. This work demonstrated a novel bright fluorescent molecule DPDTC for the sensing of mercury. The approach was mainly based on the mercury-induced fluorescence turn-off of DPDTC. The probe was prepared by a simple method and exhibited high fluorescence. The fluorescence of DPDTC was very stable and immue to photobleaching. Results showed that DPDTC was a promising tool for mercury detection. Moreover, DPDTC could be immoblized on a paper to prepare an simple and portable sensor which expanded its real application

Visualizing gaseous nitrogen dioxide by ratiometric fluorescence of carbon nanodots-quantum dots hybrid

10.1021/ac503474xAnalytical Chemistry8742087-209

Quantitative Determination of Ethylene Using a Smartphone-Based Optical Fiber Sensor (SOFS) Coupled with Pyrene-Tagged Grubbs Catalyst

For rapid and portable detection of ethylene in commercial fruit ripening storage rooms, we designed a smartphone-based optical fiber sensor (SOFS), which is composed of a 15 mW 365 nm laser for fluorescence signal excitation and a bifurcated fiber system for signal flow direction from probe to smartphone. Paired with a pyrene-tagged Grubbs catalyst (PYG) probe, our SOFS showed a wide linearity range up to 350 ppm with a detection limit of 0.6 ppm. The common gases in the warehouse had no significant interference with the results. The device is portable (18 cm × 8 cm × 6 cm) with an inbuilt power supply and replaceable optical fiber sensor tip. The images are processed with a dedicated smartphone application for RGB analysis and ethylene concentration. The device was applied in detection of ethylene generated from apples, avocados, and bananas. The linear correlation data showed agreement with data generated from a fluorometer. The SOFS provides a rapid, compact, cost-effective solution for determination of the fruit ethylene concentration dynamic during ripening for better fruit harvest timing and postharvest management to minimize wastage

Fluorescence Turn-On Detection of Gaseous Nitric Oxide Using Ferric Dithiocarbamate Complex Functionalized Quantum Dots

Functional quantum dots (QDs) grafted with ferric dithiocarbamate complex layers (QDs-Fe­(III)­(DTC)₃) were fabricated and demonstrated to be selectively reactive to nitric oxide. The dithiocarbamate (DTC) was covalently conjugated to the amine-coated QDs by a condensation reaction of the carboxyl in DTC and the amino polymer in surface of QDs. The weak fluorescence of QDs-Fe­(III)­(DTC)₃ was attributed to the energy transfer between CdSe/ZnS and Fe­(III)­(DTC)₃ complex at the surface of the functionalized quantum dots. Nitric oxide could greatly switch on the fluorescence of QDs-Fe­(III)­(DTC)₃ by displacing the DTC in the Fe­(III)­(DTC)₃ accompanied by reducing Fe­(III) to Fe­(II), thus shutting off the energy transfer way. The limit of detection for nitric oxide was estimated to be 3.3 μM and the specific detection was not interfered with other reactive oxygen species. Moreover, the probe was demonstrated for the sensing of gaseous nitric oxide, and the visual detection limit was as low as 10 ppm, showing the potential for sensing nitric oxide by the naked eye

Palladacycle Based Fluorescence Turn-On Probe for Sensitive Detection of Carbon Monoxide

New selective and sensitive fluorescence probes have always been in great demand for carbon monoxide, an important gasotransmitter molecule, which is involved in critical physiological and pathophysiological processes in the mammalian cardiovascular system. In this work, we synthesized a new palladacycle compound as a fluorescence turn-on probe for selective and quantitative detection of carbon monoxide. The weakly fluorescent probe quickly and selectively reacts with carbon monoxide and releases a highly fluorescent benzimidazole moiety, due to protonolysis of the palladacycle, which greatly enhances the fluorescence intensity. The selective reaction was against interference from other possible coexisting reactive oxygen species, and achieved a detection limit of ∼0.06 μM. Furthermore, the fluorescence turn-on probe was demonstrated with a high cellular uptake rate and was successfully applied for cell imaging of carbon monoxide in living cells

Palladacycle Based Fluorescence Turn-On Probe for Sensitive Detection of Carbon Monoxide

New selective and sensitive fluorescence probes have always been in great demand for carbon monoxide, an important gasotransmitter molecule, which is involved in critical physiological and pathophysiological processes in the mammalian cardiovascular system. In this work, we synthesized a new palladacycle compound as a fluorescence turn-on probe for selective and quantitative detection of carbon monoxide. The weakly fluorescent probe quickly and selectively reacts with carbon monoxide and releases a highly fluorescent benzimidazole moiety, due to protonolysis of the palladacycle, which greatly enhances the fluorescence intensity. The selective reaction was against interference from other possible coexisting reactive oxygen species, and achieved a detection limit of ∼0.06 μM. Furthermore, the fluorescence turn-on probe was demonstrated with a high cellular uptake rate and was successfully applied for cell imaging of carbon monoxide in living cells

Manipulating the Surface Chemistry of Quantum Dots for Sensitive Ratiometric Fluorescence Detection of Sulfur Dioxide

Herein, we report a novel approach to the rapid visual detection of gaseous sulfur dioxide (SO₂) by manipulating the surface chemistry of 3-aminopropyltriethoxysilane (APTS)-modified quantum dots (QDs) using fluorescent coumarin-3-carboxylic acid (CCA) for specific reaction with SO₂. The CCA molecules are attached to the surface amino groups of the QDs through electrostatic attraction, thus the fluorescence of CCA is greatly suppressed because of the formation of an ion-pair complex between the ATPS-modified QDs and CCA. Such an interaction is vulnerable to SO₂ because SO₂ can readily react with surface amino groups to form strong charge-transfer complexes and subsequently release the strongly fluorescent CCA molecules. The mechanism has been carefully verified through a series of control experiments. Upon exposure to different amounts of SO₂, the fluorescent color of the nanoparticle-based sensor displays continuously changes from red to blue. Most importantly, the approach owns high selectivity for SO₂ and a tolerance of interference, which enables the sensor to detect SO₂ in a practical application. Using this fluorescence-based sensing method, we have achieved a visual detection limit of 6 ppb for gaseous SO₂

Efficient Ratiometric Fluorescence Probe Based on Dual-Emission Quantum Dots Hybrid for On-Site Determination of Copper Ions

Of various chemosensory protocols, the color change observed by the naked eye is considered to be a conceivable and on-site way to indicate the presence of an analyte. We herein designed a ratiometric fluorescence probe by hybridizing dual-emission quantum dots (QDs) and demonstrated its efficiency for on-site visual determination of copper ions. The hybrid probe comprises two sizes of cadmium telluride QDs emitting red and green fluorescence, respectively, in which the red-emitting ones are embedded in silica nanoparticles and the green-emitting ones are covalently linked onto the surface. The fluorescence of the embedded QDs is insensitive to the analyte, whereas the green emissive QDs are functionalized to be selectively quenched by the analyte. Upon exposure to different amounts of copper ions, the variations of the dual emission intensity ratios display continuous color changes from green to red, which can be clearly observed by the naked eye. The limit of detection for copper is estimated to be 1.1 nM, much lower than the allowable level of copper (∼20 μM) in drinking water set by U.S. Environmental Protection Agency. The probe is demonstrated for the determination of copper ions in lake water and mineral water samples, especially for visually monitoring copper residues on herb leaves. This prototype ratiometric probe is simple, fully self-contained, and thus potentially attractive for visual identification without the need for elaborate equipment

Oxidative Cleavage-Based Near-Infrared Fluorescent Probe for Hypochlorous Acid Detection and Myeloperoxidase Activity Evaluation

A near-infrared (NIR) fluorescent probe was synthesized and demonstrated to be highly selective in reaction with hypochlorous acid (HOCl), an endogenous reactive oxygen species (ROS) produced by myeloperoxidase in neutrophils. The reaction with HOCl resulted in the NIR fluorescence quenching at 774 nm and the absorbance decreasing at 710 nm, accompanied by the appearance of a new absorption band at 520 nm. The reaction mechanism was carefully examined and proposed to proceed by initial formation of chlorohydrins and subsequent degradation. This NIR fluorescent probe was successfully applied as a selective and sensitive indicator for HOCl on the basis of either colorimetry or fluorometry, which showed detection limits of 0.13 and 0.70 μM, respectively. In addition, the molecular probe was further demonstrated for NIR fluorescence imaging of HOCl in cells and for evaluating the enzymatic activity of myeloperoxidase in the HOCl generation by measuring absorbance change

Determination of Gaseous Sulfur Dioxide and Its Derivatives via Fluorescence Enhancement Based on Cyanine Dye Functionalized Carbon Nanodots

The development of convenient methods for sulfur dioxide and its derivatives analysis is critically important because SO₂ causes worldwide serious environmental problems and human diseases. In this work, we show an unprecedented example of an energy-transfer-based fluorescence nanoprobe for selective and quantitative detection of SO₂, through molecular engineering of the fluorescent carbon nanodots by a cyanine dye which have a unique reactivity to bisulfite, achieving a detection limit of 1.8 μM with a linear relationship (<i>R</i>² = 0.9987). The specific detection was not interfered with other potential coexisted species. In addition, the probe is demonstrated for the determination of SO₂ gas in aqueous solution as well as for visually monitoring of SO₂ gas in air. This nanomaterial based probe is easily prepared, fast responding, and thus potentially attractive for extensive application for the determination of SO₂ and other similar air pollutants