Recent Trends in Monitoring of European Water Framework Directive Priority Substances Using Micro-Sensors: A 2007–2009 Review

This review discusses from a critical perspective the development of new sensors for the measurement of priority pollutants targeted in the E.U. Water Framework Directive. Significant advances are reported in the paper and their advantages and limitations are also discussed. Future perspectives in this area are also pointed out in the conclusions. This review covers publications appeared since December 2006 (the publication date of the Swift report). Among priority substances, sensors for monitoring the four WFD metals represent 81% of published papers. None of analyzed publications present a micro-sensor totally validated in laboratory, ready for tests under real conditions in the field. The researches are mainly focused on the sensing part of the micro-sensors. Nevertheless, the main factor limiting micro-sensor applications in the environment is the ruggedness of the receptor towards environmental conditions. This point constitutes the first technological obstacle to be overcome for any long-term field tests

Metal Nanostructures for Environmental Pollutant Detection Based on Fluorescence

Heavy metal ions and pesticides are extremely dangerous for human health and environment and an accurate detection is an essential step to monitor their levels in water. The standard and most used methods for detecting these pollutants are sophisticated and expensive analytical techniques. However, recent technological advancements have allowed the development of alternative techniques based on optical properties of noble metal nanomaterials, which provide many advantages such as ultrasensitive detection, fast turnover, simple protocols, in situ sampling, on-site capability and reduced cost. This paper provides a review of the most common photo-physical effects impact on the fluorescence of metal nanomaterials and how these processes can be exploited for the detection of pollutant species. The final aim is to provide readers with an updated guide on fluorescent metallic nano-systems used as optical sensors of heavy metal ions and pesticides in water

Electrochemical sensors and devices for heavy metals assay in water: the French groups’ contribution

A great challenge in the area of heavy metal trace detection is the development of electrochemical techniques and devices which are user-friendly, robust, selective, with low detection limits and allowing fast analyses. This review presents the major contribution of the French scientific academic community in the field of electrochemical sensors and electroanalytical methods within the last 20 years. From the well-known polarography to the up-to-date generation of functionalized interfaces, the different strategies dedicated to analytical performances improvement are exposed: stripping voltammetry, solid mercury-free electrode, ion selective sensor, carbon based materials, chemically modified electrodes, nano-structured surfaces. The paper particularly emphasizes their advantages and limits face to the last Water Frame Directive devoted to the Environmental Quality Standards for heavy metals. Recent trends on trace metal speciation as well as on automatic “on line” monitoring devices are also evoked

Development of a rapid screening technique for contaminants in environmental monitoring and regulation

Rapid screening technique is important and efficient for routine monitoring of chemical pollutants, risk assessment and decision making in dealing with contaminants in waters and soils. The focus of this thesis is on developing simple and rapid screening methods based on the diffusive gradients in thin films (DGT) technique to assess the concentration of phosphorus and metals qualitatively and quantitatively. Firstly, a rapid detection technique for phosphorus based on Metsorb DGT devices and a colour imaging method using the conventional molybdenum blue were developed and fully tested under different conditions. The fully quantitative interpretation of the P concentration can be assessed in the linear range of 0.1 to 1.02 μg cm-2 device that corresponds to the concentration range of 9 to 98 μg L-1 if the deployment time is 24 hours and the water temperature is 20oC. Secondly, digital colorimetric analysis using a flat-bed scanner was utilised to quantify the Cu, Ni, and Co in water following the DGT uptake of metals by Chelex resin gel without involving further reactive reagents. The fully quantitative interpretation of the Cu, Ni, and Co concentration can be assessed in the linear range of 1.5 to 165 μg cm-2 , 2.7 to 153 μg cm-2 , and 1.6 to 159.2 μg cm-2 , respectively, which correspond to the concentration range of 0.05 to 5 mg L-1 for all three metals if the deployment time is 24 hours and the water temperature is 20oC. Thirdly, a rapid screening technique for Cr(VI) using DGT and a high-resolution CID base on the surface colouration of the N-Methyl-D-glucamine (NMDG) binding gel has been developed. The relationship between the accumulation of Cr(VI) in NMDG gels and the corresponding change in grayscale intensity was well fitted using a quintic polynomial. The fully quantitative interpretation of the Cr(VI) concentration can be assessed in the linear range of 0.31 to 2.47 μg cm-2 which correspond to the concentration range of 12.5 to 150 μg L-1 if the deployment time is 24 hours and the water temperature is 20oC. This study has formulated a DGT deployment guide list to determine whether the concentration of metals has exceeded the maximum contaminant level allowed based on the regulation standards in different countries and regions. The use of both a simple visual inspection and a scanner for DGT devices at different deployment times and different temperatures will be considered for this list. Moreover, the rapid screening technique has been evaluated in water and soil from five regions in China. Furthermore, a novel approach with biological material incorporated in the DGT (Bio-DGT) was developed to measure the concentrations and toxicity of metals at the same time in water and soil. The new method immobilised a whole-cell toxicity bioreporter, ADPWH_recA, into a thin layer of agarose gel to replace the polyacrylamide gel that is commonly used in DGT. The test results indicated that the concentrations of metals measured by Bio-DGT and the cell free DGT have no significant differences during a 7-day deployment in synthetic water. A positive metal exposure relationship was shown between Bio-DGT accumulation and biological response. Bio-DGT showed a stable response to heavy metals under a wide range of pH and ionic strength. The bioluminescent signal of Bio-DGT was maintained at a high level during up to 30 days of storage. The deployment of Bio-DGT devices in field soils collected from China allowed the measurement of both the available concentration and the toxicity of metals. It indicated that the new Bio-DGT can assess the bioavailability and toxicity of metals at the same time. The newly developed rapid screening technique for P and metals were applied in waters and soils in situ in 5 different regions of China. It showed the concentrations of P in most of the monitored waters in Beijing were low and the quality of the waters has reached the Chinese water quality standards for surface water. The concentration of DGT-measured P in the two main rivers run through Tianjing were higher than the national water standard in China. The concentrations of Cu in monitored aquatic systems of all field areas have also reached the Chinese water quality standards for surface water

The Mathematical Modeling for CoO(OH) – Poly(5-Amino-1,4-Naphthoquinone) Composite-Based Sensor for 1-Propenesulfenic Acid and Propanethial S-Oxide Detection in Food and Lacrimogenic Compositions

Abstract: The theoretical description for 1-propenesulfenic acid and its isomer propanethial-S-oxide, substances, responsible for leek lacrimogenic activity, has been described theoretically. The process is realized anodically over a poly(naphthoquinone) – CoO(OH) composite. A model has been developed and analyzed using linear stability theory and bifurcation analysis. According to the model analysis, the ionic compound's transformation during the sulfenic acid oxidation may be responsible for the oscillatory and monotonic instability alongside the double electric layer (DEL) influences of the electrochemical stage. Nevertheless, the model's analysis shows that the electroanalytical process is efficient for determining both of the analytes

Advancements in Biomonitoring and Remediation Treatments of Pollutants in Aquatic Environments

This book is a collection of a group of peer-reviewed scientific papers dealing with both the evaluation and the solution of the complex but pressing problem of water source pollution. In the case of both fresh and marine water, the environmental and health protection aspects are closely linked. Monitoring activities supply continuous information on the contamination levels in inland surface, ground, and coastal waters, providing an alert in case of increased or new contamination and monitoring the effectiveness of remediation strategies. On the other hand, new or improved remediation and bioremediation tools are urgently needed to tackle the scarcity of safe drinking water. The papers in this book represent interesting starting points for future researches

Luminescent Metal-Organic Frameworks for Electrochemiluminescent Detection of Water Pollutants

Modern lifestyle has increased our utilization of pollutants such as heavy metals, aromatic 17 compounds, and contaminants of rising concern involving pharmaceutical and personal products 18 and other materials that may have an important environmental impact. Especially, the ultimate re-19 sults of intense use of highly stable materials, such as heavy metals and chemical restudies are that 20 they turn into waste materials which, when discharged, accumulate in the environment water bod-21 ies. In this context, the present review presents application of metal-organic frameworks (MOFs) in 22 electrochemiluminescent (ECL) sensing for water pollutant detection. MOF composites applied as 23 innovative luminophore or luminophore carriers, materials for electrode modification and enhance-24 ment of co-reaction in ECL sensors have enabled sensitive monitoring of some most common con-25 taminants of emerging concern such as heavy metals, volatile organic compounds, pharmaceuticals, 26 industrial chemicals and cyanotoxins. Moreover, we provide future trends and prospects associated 27 with ECL MOF-composites for environmental sensing

Regulating services

No abstract available

Real-Time, Selective Detection of Heavy Metal Ions in Water Using 2d Nanomaterials-based Field-effect Transistors

Excessive intake of heavy metals damages the central nervous system and causes brain and blood disorders in mammals. Heavy metal contamination is commonly associated with exposure to mercury, lead, arsenic, and cadmium (arsenic is a metalloid, but classified as a heavy metal). Traditional methods to detect heavy metal ions include graphite furnace atomic absorption spectroscopy (GFAAS), inductively-coupled plasma optical emission spectroscopy (ICP-OES), and inductively-coupled plasma mass spectroscopy (ICP-MS). Recently, many new methods have been proposed to detect heavy metal ions, including atomic absorption spectrometry, fluorescent sensors, colorimetric sensors, electrochemical sensors, X-ray absorption fine structure spectroscopy, ultrasensitive dynamic light scatting assays, and ion selective electrodes. Although significant progress has been made, there are still some critical issues to be addressed, e.g., lack of portability, the need for well-trained personnel, highly expensive and complex instruments, long response time (tens of minutes or even longer), and the possibility of introducing additional contamination. Therefore, it is highly desirable to develop a real-time, low-cost, portable, user-friendly analytical platform for rapid inline analysis of mercury, lead and other heavy metal ions. This dissertation research aims to investigate field-effect transistor (FET) sensors based on two-dimensional (2D) nanomaterials with specific probe-functionalized gold (Au) nanoparticles (NPs). The fundamental mechanism of the FET platform is to use a 2D nanomaterial as the conducting channel to transport charge carriers (electrons or holes). Upon the capture of target analytes, the charge carrier concentration and/or mobility changes correspondingly with a signal of current change within the channel. As a result, the FET characteristic changes upon the introduction of the heavy metal ion solution, varies with the metal concentration, and takes only a few seconds to respond. Control experiments are performed to verify the selectivity of the 2D nanomaterial/Au NP hybrid sensor to specific targets. The rapid, selective, sensitive, and stable detection performance indicates the promise of 2D nanomaterial/Au NP hybrid sensors for heavy metal ion detection in an aqueous solution. This research is accomplished through several steps: First, various heavy metal ion contaminants, their damage, and the conventional detection methods are reviewed; Second, the FET-based plaform and its working mechanism are explored; Third, the understanding of various 2D nanomaterials, their unique properties pertinent to electronic sensing, and their selection to realize real-time, selective, and sensitive detection of heavy metal ions is carried out; Finally, improvement of stability, sensitivity and lifetime of FET sensors is investigated. In this thesis work, sensitive and selective FET-based 2D nanomaterial/Au NP hybrid sensors for Pb2+, Hg2+, As(III), and As(V) have been demonstrated. The 2D nanomaterials include reduced graphene oxide (rGO), molybdenum disulfide (MoS2), and black phosphorus (BP). The hybrid structure consists of a nanomaterial film, homogeneously dispersed Au NPs, and specific probes. The detection is enabled by recording the electrical conductance of the device through monitoring the change in the drain current of the 2D nanomaterial sheets. The platform offers a promising route for real-time (1-2 seconds), high-performance and low-cost detection of heavy metal ions. The lower detection limit can reach the order of µg/L (parts-per-billion or ppb). The sensor also shows high selectivity against other co-existing metal ions. To improve the sensitivity of the nanomaterial-based electronic sensor, theoretical analysis on the sensing mechanism has been carried out, together with experimental validation. Theoretical analysis indicates that sensitivity-related factors are semiconducting properties of nanomaterials (e.g., carrier mobility, band gap), number of probes, and adsorption capacity of Au NPs. Experimental results suggest that a higher sensitivity for sensors can be realized by forming hybrid structures with thinner 2D conducting materials with a larger band gap and a higher carrier mobility, increasing the areal density of anchoring sites on the sensor surface, and enhancing the adsorption of detection probes. Investigation into the stability of the nanomaterial-based electronic sensor includes the binding strength between the nanomaterial and electrodes, stability of the nanomaterials in ambient environment and water, the detachment of Au NPs, the lifetime and diffusion of probes, and the overall stability of the sensor platform. Subsequently, strategies to improve the stability of the nanomaterial-based FET sensor have been proposed. Finally, the FET sensor has been used for the accurate prediction of arsenic ions in lake water and integrated into a practical flowing water system for continuous detection of lead ions. The rapid, selective, sensitive, and stable detection performance of the FET sensor for various heavy metal ions in water suggests a promising future for in-situ detection of contamination events. The thesis study provides a scientific foundation to engineer FET sensors with enhanced performance. An attempt has been made to practically develop the FET platform into standalone sensors and to integrate the sensor into flowing water equipment for heavy metal ion detection. The thesis results thus contribute to the future application of FET sensors for monitoring water contamination and mitigating the public health risk

Electrochemical Determination of Sudan Dyes and Two Manner to Realise it a Theoretical Investigation

In this work, a general theoretical description of the electrochemical determination of Sudan dyes by cathodic and anodic route has been made. Two mathematical models have been developed for each case, being, afterward, analyzed by means of linear stability theory and bifurcation analysis. It has been shown that in both cases, the systems are efficient from the electroanalytical point of view. The possibility for the oscillatory and monotonic instability has also been verified