Real River Research Articles

A simple high-throughput headspace gas chromatographic method for the determination of dissolved oxygen in aqueous samples

This paper reports on a headspace gas chromatographic method (HS-GC) for the accurate determination of dissolved oxygen (DO) in domestic and industrial wastewater. It was based on GC measurement of oxygen in the headspace gas that is released from the dissolved oxygen in a liquid sample in a closed vial. The results show that the relative standard deviation of the method in quintuplicate testing was < 2.0% and the relative differences of results were less than 4.0% for the real river water samples when compared with the widely used reference method (the electrode method); The linear range of the method is about 0–9.0 mg/L with the limit of detection of 0.30 mg/L. The present method is simple in both sample preparation and method calibration. It is particularly efficient in the batch testing mode. Overall, the method is more reliable than the current reference method when used with samples from a wide range of sources.

Organosilane-functionalized carbon quantum dots and their applications to "on-off-on" fluorometric determination of chromate and ascorbic acid, and in white light-emitting devices.

Organosilane-functionalized carbon quantum dots (Si-CQDs) were synthesized by reacting glucosamine and 3-[2-(2-aminoethylamino)ethylamino]propyl-trimethoxysilane in acetone. The surface morphology, crystal structure, functional groups, elemental composition, and optical properties of the Si-CQDs were characterized using TEM (HRTEM), XRD, FT-IR, XPS, UV-vis absorption and fluorescence spectroscopy. They show that N-containing groups including C=N and C-N, and Si-containing groups including Si-O-C and Si-O-Si have beenformed on the surface of Si-CQDs. The element doping and surface functionalization of Si-CQDs endow their novel chemical, physical and optical properties. The Si-CQDs dispersed in acetone are almost monodisperse with an average particle diameter of 3.6nm. The Si-CQDs dispersed in acetone display blue fluorescence (excitation/emission maxima of 380/460nm). In contrast, the solid-state Si-CQDs exhibited yellow fluorescence (with excitation/emission maxima of 470/595nm). The fluorescence emission spectra of acetone-suspended Si-CQDs are concentration-dependent, and the emission peak becomes red-shifted as the concentration is increased. The Si-CQDs are sensitive and selective fluorescent "on off on" nanoprobes for chromate [Cr(VI)] and ascorbic acid (AA). Fluorescence is quenched by Cr(VI) via an inner filter effect from the absorption of Si-CQDs excitation at 380nm by Cr(VI). Upon addition of AA, fluorescence is restored because of reduction of Cr(VI) by AA. Under optimal conditions (excitation/emission wavelength of 380/460nm), the response is linear in the 0.4-160μM Cr(VI) concentration range, and the detection limit is 34nM. The respective data for AA are 1-80μM and 84.6nM. The practical use of the nanoprobe for Cr(VI) determination in real river water samples is also demonstrated successfully. Their concentration-dependent fluorescence, good thermal stability and self-crosslinking behavior also make the Si-CQDs a candidate material for white light-emitting diodes that displays color conversion and can act as an encapsulation layer in a blue light-emitting diode (LED) chip. Graphical abstract One-pot solvothermal synthesis of organosilane-functionalized carbon quantum dots (Si-CQDs) with blue fluorescence in solution, yellow fluorescence in solid state and concentration-dependent fluorescence property, and their applications for chromate (Cr(VI)) and ascorbic acid dual determinations and white light-emitting device. Graphical Abstract contains poor quality and small text inside the artwork. Please do not re-use the file that we have rejected or attempt to increase its resolution and re-save. It is originally poor, therefore, increasing the resolution will not solve the quality problem. We suggest that you provide us the original format. We prefer replacement figures containing vector/editable objects rather than embedded images. Preferred file formats are eps, ai, tiff and pdf.We have changed the poor quality graphical abstract into the jpg and pdf.

Comparison of the removal of 21 micropollutants at actual concentration from river water using photocatalysis and photo-Fenton

The development of technologies capable of eliminating a wide spectrum of micropollutants of diverse nature from waters becomes essential. Advanced oxidation processes (AOPs) seem to be the most promising technologies but the most appropriate AOP to remove the micropollutants is still under debate. In this study, for the first time, the comparison of the efficiency of TiO2 heterogeneous photocatalysis and iron-impregnated faujasite heterogeneous photo-Fenton process is conducted towards the removal of a mixture of 21 micropollutants from a real river at low concentrations. The sampling area is situated on the Meurthe River, downstream the wastewater treatment plant of the city of Nancy in the northeast of France. To assess the impact of the micropollutants concentration and the matrix composition, two sampling campaigns have been performed at different periods of the year. Among the targeted micropollutants, 14 pharmaceuticals, 1 personal care product, 4 endocrine disruptors and 2 perfluorinated molecules are specifically followed. Their concentrations range from few ng L−1 to hundreds ng L−1. The adsorption of all the micropollutants is higher onto the iron-impregnated faujasite compared to that onto TiO2 due to the larger surface area of the iron-impregnated faujasite. The iron-impregnated faujasite offers superior photo-Fenton oxidation efficiency towards the degradation of the micropollutants over the TiO2 photocatalysis system. For almost all the micropollutants, the contaminants are totally removed after 30 min by photo-Fenton while a longer period is necessary by photocatalysis. A relationship between the removal efficiencies and the octanol–water partition coefficient (log Kow) of each micropollutant has been extracted from the data. A further economic evaluation confirms that the photo-Fenton process is also the better in terms of cost.

Real Time River Bridge Monitoring and Alert System using GSM

International Journal of Computer Sciences and Engineering (A UGC Approved and indexed with DOI, ICI and Approved, DPI Digital Library) is one of the leading and growing open access, peer-reviewed, monthly, and scientific research journal for scientists, engineers, research scholars, and academicians, which gains a foothold in Asia and opens to the world, aims to publish original, theoretical and practical advances in Computer Science,Information Technology, Engineering (Software, Mechanical, Civil, Electronics & Electrical), and all interdisciplinary streams of Computing Sciences. It intends to disseminate original, scientific, theoretical or applied research in the field of Computer Sciences and allied fields. It provides a platform for publishing results and research with a strong empirical component. It aims to bridge the significant gap between research and practice by promoting the publication of original, novel, industry-relevant research.

A Simple and Label-Free Detection of As3+ using 3-nitro-L-tyrosine as an As3+-chelating Ligand.

A simple and rapid As3+ detection method using 3-nitro-L-tyrosine (N-Tyr) is reported. We discovered the specific property of N-Tyr, which specifically chelates As3+. The reaction between As3+ and N-Tyr induces a prompt color change to vivid yellow, concomitantly increasing the absorbance at 430 nm. The selectivity for As3+ is confirmed by competitive binding experiments with various metal ions (Hg2+, Pb2+, Cd2+, Cr3+, Mg2+, Ni2+, Cu2+, Fe2+, Ca2+, Zn2+, and Mn2+). Also, the N-Tyr binding site, binding affinity, and As3+/N-Tyr reaction stoichiometry are investigated. The specific reaction is utilized to design a sensor that enables the quantitative detection of As3+ in the 0.1–100 μM range with good linearity (R2 = 0.995). Furthermore, the method’s applicability for the analysis of real samples, e.g., tap and river water, is successfully confirmed, with good recoveries (94.32–109.15%) using As3+-spiked real water samples. We believe that our discovering and its application for As3+ analysis can be effectively utilized in environmental analyses such as those conducted in water management facilities, with simplicity, rapidity, and ease.

Methodology for improving reliability of river discharge measurements

Programs to monitor water characteristics are undertaken to identify any possible water pollution of a river. To compute reliable water pollution loads, accurate river discharge and pollutant/tracer concentrations are required. When pollutants/tracers are measured with sufficient precision, the accuracy of river discharge measurements becomes the most critical parameter of the pollutant load computation, as well as the largest error source. The absence of permanent measuring equipment in many rivers is a common difficulty for the implementation of monitoring programs. Alternatively, quick measurement methods which are low in cost and reliability (e.g. floats) are often employed to get an estimate of river discharges, when there are budgetary and time restrictions. In this paper, an original technique, mainly for use in ungauged rivers, is proposed for correcting river discharge measurements which have low levels of accuracy; this in turn would correct pollutant concentrations. A nonlinear optimization problem is developed based on water volume and pollutant mass conservation principles for river balance nodes, taking into consideration non-measurable latent quantities. Parallel measurements of discharge and tracers for representative cross-sections of a river and its tributaries are required. The measurement conditions should refer to the steady-state hydraulic conditions usually prevailing in the flow under consideration. In order to test the reliability of the method, a virtual river example is built, defining the real values of water characteristics and generating measurement sets via Monte-Carlo simulations combining random and systematic errors. For more than 92% of the generated measurement sets, the proposed technique results in a successful and acceptable correction for the total of the measured cross-sections. Finally, the method is applied to a real river and the measurements are corrected successfully.

Wavelet‐Based River Segmentation Using Hydraulic Control‐Preserving Water Surface Elevation Profile Properties

AbstractRiver flow models that consider satellite observations of the water surface elevation (WSE) require meaningful segmentation into reaches. Segmentation methods involve a trade‐off between the spatial sampling and error characteristics of satellite observations, both of which impact the flow model realism/accuracy. This paper investigates the spatial properties of WSE profiles (slope and concavity) and their link with hydraulic controls (HCs) and leverages this knowledge to advance river segmentation. Fine‐scale synthetic cases were analyzed to characterize HC effects on the remotely observable WSE properties. Following this, a wavelet‐based segmentation method was developed and subsequently tested on real rivers, including test cases with measurements characteristic of the Surface Water and Ocean Topography satellite mission. The results show that the local extrema of water surface (WS) concavity are good candidates for defining reach bounds while consistently preserving the HC signatures and local flow nonuniformities (deviations from equilibrium) from fine to large spatial scales.

Ratiometric fluorescent sensing of Pb2+ and Hg2+ with two types of carbon dot nanohybrids synthesized from the same biomass

This work initially describes two ratiometric fluorescent nanosensors that use dual- and three-emission carbon dot (CD) nanohybrids for highly sensitive detection of sub-nanomolar Pb2+ and Hg2+, respectively. The two new types of CD hybrids are prepared via solvothermal treatment of the same extracts of bamboo leaves. This strategy is facile, cost-effective, environmentally-friendly and useful, as it avoids the post-modification of CDs or their mixing with other fluorescent probes which are typically adopted in most of CD-based ratiometric nanosensors previously reported. More importantly, the utilities of the two new nanosensors that enable built-in correction of external effects are well demonstrated by achieving detection limits as low as ˜0.14 and 0.22 nM (3σ) for Pb2+ and Hg2+, respectively. This makes them be among the most sensitive systems currently available for sensing the two analyte ions. The satisfactory recovery results of analyzing a series of real river water examples additionally validate their feasibilities for practical applications. To the best of our knowledge, this may be the first report of applying the same natural biomass as raw material to synthesize two types of multi-emission CD hybrids for ratiometric sensing. Considering their simplicity, low cost, good sensitivity and specificity, and accuracy, the developed ratiometric fluorescent nanosensors hold great potential to find wide applications in environmental monitoring, water safety, and waste management.

Improvement of surface run‐off in the hydrological model ParFlow by a scale‐consistent river parameterization

AbstractWe propose an improvement of the overland‐flow parameterization in a distributed hydrological model, which uses a constant horizontal grid resolution and employs the kinematic wave approximation for both hillslope and river channel flow. The standard parameterization lacks any channel flow characteristics for rivers, which results in reduced river flow velocities for streams narrower than the horizontal grid resolution. Moreover, the surface areas, through which these wider model rivers may exchange water with the subsurface, are larger than the real river channels potentially leading to unrealistic vertical flows. We propose an approximation of the subscale channel flow by scaling Manning's roughness in the kinematic wave formulation via a relationship between river width and grid cell size, following a simplified version of the Barré de Saint‐Venant equations (Manning–Strickler equations). The too large exchange areas between model rivers and the subsurface are compensated by a grid resolution‐dependent scaling of the infiltration/exfiltration rate across river beds. We test both scaling approaches in the integrated hydrological model ParFlow. An empirical relation is used for estimating the true river width from the mean annual discharge. Our simulations show that the scaling of the roughness coefficient and the hydraulic conductivity effectively corrects overland flow velocities calculated on the coarse grid leading to a better representation of flood waves in the river channels.

Riparian Vegetation and Sediment Supply Regulate the Morphodynamic Response of an Experimental Stream to Floods

Feedbacks between woody plants and fluvial morphodynamics result in co-development of riparian vegetation communities and channel form. To advance mechanistic knowledge regarding these interactions, we measured the response of topography and flow to the presence of riparian tree seedlings with contrasting morphologies in an experimental, field-scale, meandering stream channel with a mobile sand bed. On a convex point bar, we installed seedlings of Tamarix spp. (tamarisk) and Populus fremontii (cottonwood) with intact roots and simulated a bankfull flood, with each of eight runs varying sediment supply, plant density, and plant species. Vegetation reduced turbulence and velocities on the bar relative to bare-bed conditions, inducing sediment deposition when vegetation was present, regardless of vegetation density or species. Sediment supply also played a dominant role, and eliminating sediment supply reduced deposition regardless of the presence of vegetation. Unexpectedly, plant density and species architecture (shrubby tamarisk versus single-stemmed cottonwood) had only a secondary influence on hydraulics and sediment transport. In the absence of plants, mobile bedforms were prominent across the bar, but vegetation of all types decreased the height and lateral extent of bedforms migrating across the bar, suggesting a mechanism by which vegetation modulates feedbacks among sediment transport, topography, and hydraulics. Our measurements and resulting insights bridge the gap between laboratory conditions and real dryland sand-bed rivers and motivate further morphodynamic modeling.

Task-specific solid-phase microextraction based on ionic liquid/polyhedral oligomeric silsesquioxane hybrid coating for sensitive analysis of polycyclic aromatic hydrocarbons by gas chromatography–mass spectrometry

A direct immersion solid-phase microextraction (DI-SPME) approach for gas chromatography-mass spectrometry (GC–MS) based on hybrid fiber coating of ionic liquid and polyhedral oligomeric silsesquioxane (POSS) is presented. To fabricate the task-specific coating for the enrichment of polycyclic aromatic hydrocarbons (PAHs), 1-butyl-3-vinylimidazolium bis[(trifluoromethyl)sulfonyl]imide (IL) and POSS were rapidly photoinitiated copolymerized within 5 min on a stainless steel fiber. The high efficient extraction of target analytes can be attributed to a combined result of multiple interactions including the strong CF⋯HC pseudohydrogen bonding, π-π stacking, hydrophobic force, and molecular sieve effect. A wide linear range (0.04–400 ng L−1) with low detection limits in the range of 0.004 and 0.5 ng L−1 were obtained for PAHs by GC–MS. The applicability of this coupling method was successfully demonstrated by the analysis of trace PAHs in real river water and soil samples, with satisfied recoveries (84.2–108.6%) and relative standard deviations (<8.1%). Compared to the other commercial fiber-based SPME methods, the IL/POSS hybrid coating-based SPME is much cheaper, thermally stable and capable of eliminating possible deleterious effects as well.

Green and microwave-assisted synthesis of carbon dots and application for visual detection of cobalt(II) ions and pH sensing

A facile, economical, and green method for the preparation of carbon dots (CDs) was established via microwave irradiation using green natural material kelp as the main carbon source and ethylenediamine as nitrogen dopant. The as-prepared CDs were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), fluorescence spectrophotometer and UV–vis absorption spectra. Furthermore, the CDs showed high sensitivity toward pH and cobalt(II) ion(Co2+). To be specific, the fluorescence intensity of CDs exhibited a linear relationship over the pH range from 3 to 8, and the CDs were applied in the visual detection of Co2+. With the addition of Co2+, the color change (from colorless to brownish yellow under visible light and from bright blue to dark blue under ultraviolet light) of the solution can be clearly seen with the naked eye. Under optimal conditions, the CDs enabled selective detection of Co2+ with a linear range of 1–200 μmol/L and a limit of detection with 0.39 μmol/L. Finally, this method was applied in the analysis of real river water samples.

Removal of Methylene Blue Dye from Water using Ecofriendly Waste Product (Eggshell) as an Adsorbent and Using the Optimum Adsorption Conditions with Real Water Sample from Tigris River

Environmental pollution is a worldwide issue that affects the human being health, water pollution is one of the causes of this phenomenon. Dyes represent the raw materials in many industries such as textile, paper, plastic and leather industries as well as they considered as toxic water pollutants. The adsorption method is one of the most effective methods for removing dyes from polluted water. In this search, ecofriendly food waste (eggshell) was used as an adsorbent for removing methylene blue dye (MB) from waste water. In this research, eggshell morphology was studied using Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray (EDX). The stability of the eggshell adsorbent was tested by Thermal Gravimetric Analysis (TGA). Whereas checking with various MB dye concentration for eggshell the maximum adsorption was noticed at (8ppm) and this concentration was used for further optimization. MB solutions was prepared at pH 7.2 and at 21℃ same conditions as in Tigris River water which was used to compare the activity of the eggshells adsorbent using analytical standard MB solutions and on the other hand using real sample solutions. The results show that using eggshells adsorbent with standards solution and real sample solutions of MB provide the same general trends with respect to MB removal. Consequently, using eggshell as an ecofriendly adsorbent was successfully tested to be used with both MB analytical standard solutions and real river MB solutions.

Optimal UAV Route Planning for Coverage Search of Stationary Target in River

In this brief, we focus on the offline route planning of unmanned aerial vehicle (UAV) for the coverage search mission in a river region. Given the prior likelihood distribution of area importance, this brief aims to generate UAV feasible routes which maximize the cumulative probability of finding a single and stationary target within the required time. First, Gaussian mixture model is used to approximate the prior likelihood distribution, and several river segments with high detection probability corresponding to Gaussian components can be extracted. With the consideration of quantified factors, the river subregions are prioritized by the approximation insertion method and then allocated to UAVs. Moreover, to meet the terminal time constraint, the so-called positive/negative greedy method is proposed to expand or contract waypoints. Finally, the performance of our proposed algorithm is evaluated by simulations on a real river map, and the results verify its good performance in various scenarios.

Degradation of 4-nonylphenol in marine sediments by persulfate over magnetically modified biochars

In this study, an environmentally friendly and economically viable bamboo biochar (BB) was modified by Fe3O4 and was applied for the treatment of real river sediments containing the endocrine disruptor chemical (EDC) 4-nonylphenol (4-NP). The microporosity of Fe3O4–BB was clearly observed from the N2 adsorption isotherms. The catalytic performance of Fe3O4–BB is highly dependent on pH and the catalyst dosage. The degradation efficiency of 4-NP (85%) was achieved at pH 3.0 using an initial dosage of 3.33 g L−1 Fe3O4–BB and 2.3 × 10−5 M persulfate (PS) in a biochar–sediment system. The kinetic behavior of 4-NP degradation with catalysis can be accounted by using the Langmuir-Hinshelwood type kinetic model. The MTT assay results indicated that Fe3O4–BB has a low potent cytotoxic effect and is therefore suitable for application in remediation of contaminated sediment.

Simultaneous voltammetric sensing of levodopa, piroxicam, ofloxacin and methocarbamol using a carbon paste electrode modified with graphite oxide and β-cyclodextrin.

A carbon paste electrode (CPE) was modified with graphite oxide (GrO) and β-cyclodextrin (CD) to obtain a sensor for simultaneous voltammetric determination of levodopa (LD), piroxicam (PRX), ofloxacin (OFX) and methocarbamol (MCB). The morphology, structure and electrochemical properties of the functionalized GrO were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, contact angle measurements and cyclic voltammetry. Under the optimal experimental conditions, the sensor is capable of detecting LD, PRX, OFX and MCB by square wave voltammetry (SWV) at working potentials of +0.40, +0.60, +1.03 and + 1.27V (versus Ag/AgCl), respectively. Response is linear from 1.0 to 20μM for LD, from 1.0 to 15μM for PRX, from 1.0 to 20μM for OFX, and from 1.0 to 50μM for MCB. The respective limits of detection are 65, 105, 89 and 400nM. The method was successfully applied to the simultaneous determination of LD, PRX, OFX and MCB in (spiked) real river water and synthetic urine samples, and the results were in agreement with those obtained using a spectrophotometric method, with recoveries close to 100%. Graphical abstract Schematic presentation of a novel electroanalytical method employing a carbon paste electrode modified with graphite oxide and β-cyclodextrin for the simultaneous determination of levodopa, piroxicam, ofloxacin and methocarbamol in urine and river water samples by square wave voltammetry.

Supramolecular Hybrid Material Based on Engineering Porphyrin Hosts for an Efficient Elimination of Lead(II) from Aquatic Medium.

Porphyrins show great promise for future purification demands. This is largely due to their unique features as host binding molecules that can be modified at the synthetic level, and largely improved by their incorporation into inorganic based materials. In this study, we assessed the efficacy of a hybrid material obtained from the immobilization of 5,10,15,20-tetrakis(pentafluorophenyl)-porphyrin on silica surface to remove Pb(II), Cu(II), Cd(II), and Zn(II) ions from water. The new organic-inorganic hybrid adsorbent was fully characterized by adequate techniques and the results show that the hybrid exhibits good chemical and thermal stability. From batch assays, it was evaluated how the efficacy of the hybrid was affected by the pH, contact time, initial metal concentration, and temperature. The adsorption kinetic and isotherms showed to fit the recent developed fractal-like pseudo-second-order model and Langmuir–Freundlich model respectively. The highest adsorption capacities for Pb(II), Cu(II), Cd(II), and Zn(II) ions were 187.36, 125.17, 82.45, and 56.23 mg g−1, respectively, at pH 6.0 and 25 °C. This study also shows that metal cations from real river water samples can be efficient removed in the presence of the new adsorbent material.

Biosynthesized Highly Stable Au/C Nanodots: Ideal Probes for the Selective and Sensitive Detection of Hg2+ Ions.

The enormous ongoing industrial development has caused serious water pollution which has become a major crisis, particularly in developing countries. Among the various water pollutants, non-biodegradable heavy metal ions are the most prevalent. Thus, trace-level detection of these metal ions using a simple technique is essential. To address this issue, we have developed a fluorescent probe of Au/C nanodots (GCNDs-gold carbon nanodots) using an eco-friendly method based on an extract from waste onion leaves (Allium cepa-red onions). The leaves are rich in many flavonoids, playing a vital role in the formation of GCNDs. Transmission electron microscopy (TEM) and Scanning transmission electron microscopy-Energy-dispersive X-ray spectroscopy (STEM-EDS) elemental mapping clearly indicated that the newly synthesized materials are approximately 2 nm in size. The resulting GCNDs exhibited a strong orange fluorescence with excitation at 380 nm and emission at 610 nm. The GCNDs were applied as a fluorescent probe for the detection of Hg2+ ions. They can detect ultra-trace concentrations of Hg2+ with a detection limit of 1.3 nM. The X-ray photoelectron spectroscopy results facilitated the identification of a clear detection mechanism. We also used the new probe on a real river water sample. The newly developed sensor is highly stable with a strong fluorescent property and can be used for various applications such as in catalysis and biomedicine.

Degradation of bisphenol A by activating peroxymonosulfate with Mn0.6Zn0.4Fe2O4 fabricated from spent Zn-Mn alkaline batteries

Spinel ferrites have shown great potential to activate peroxides for environmental remediation. In this work, a Mn-Zn ferrite catalyst was fabricated by the citrate combustion method from spent Zn-Mn alkaline batteries. The synthesized Mn0.6Zn0.4Fe2O4 catalysts were applied to activate peroxomonosulfate (PMS) and degrade bisphenol A (BPA) in water. A 95.8% BPA (0.1 mM) removal was achieved at initial pH of 6.2, Mn0.6Zn0.4Fe2O4 dosage of 0.2 g/L, PMS concentration of 0.5 mM, and reaction time of 60 min. The concentration of metal leaching and radical identification experiments suggested that BPA is mainly degraded by surface-adsorbed reactive radicals. Metals at A site of the spinel (AFe2O4, A = Mn and Zn) were responsible for PMS activation and Fe(III) acted as the reservoir for the surface hydroxyl groups, which substantially accelerated the degradation of BPA. The addition of Cl− improved the destruction of BPA and a NaHCO3 concentration below 5 mM had a negligible effect on the BPA removal. When the PMS/Mn0.6Zn0.4Fe2O4 process was used to treat real river water spiked with BPA, the removal of BPA was much faster than that in deionized water. This implied that the PMS/Mn0.6Zn0.4Fe2O4 process may provide some new insights not only for the recycling of spent batteries, but also for removal of contaminants from wastewater.

Colorimetric copper ion sensing in solution phase and on paper substrate based on catalytic decomposition of S-nitrosothiol

A S-nitrosothiol (RSNO) is used for highly selective and sensitive copper ion sensing for the first time. Cu(II) in the sample is reduced to Cu(I) by a low amount of thiols generated from hydrolysis of RSNO molecules or added thiols such as l-glutathione or l-cysteine. Cu(I) is able to trigger cleavage of the SNO bond, which converts colored RSNOs to colorless products. The dark green S-nitroso-N-acetylpenicillamine is used as an exemplary RSNO in this report. In the spectrophotometric test, the detection limit toward Cu(II) is 0.23 μM without added thiol reductants, and 0.08 and 0.06 μM in the presence of l-glutathione and l-cysteine, respectively. Furthermore, we prepared fully inkjet printed paper-based sensors by deposition of all reaction reagents and buffers on the same piece of cellulose paper. A smartphone equipped with a color analysis app enables quantification of the color change of the paper-based Cu(II) sensors. In this method, a detection limit of 1.2 μM and a linear range of 0–10 μM were obtained. Finally, we successfully applied this instrumentation-free and reagent-free senor for Cu(II) analysis in real drinking water and river water samples.