Real Seawater Samples Research Articles

Naphthalene-based silica nanoparticles as a highly sensitive fluorescent chemosensor for mercury detection in real seawater

Mercury is considered one of the most harmful contaminants threatening human lives and the aquatic environment. Naphthalene and its derivatives have excellent fluorescence properties that can be exploited for mercury (Hg2+) sensing applications. Herein, we covalently attached naphthalene with silica nanoparticles (NSPs) using one-pot multiple steps synthesis approach. The NSPs were characterized by 1H NMR, FTIR, TGA, FESEM, and UV–vis spectroscopy. The fluorescent properties were analyzed in deionized water under normal and UV-light illumination. Finally, the synthesized NSPs were investigated as a chemosensor for Hg2+ ions detection in real seawater samples via photoluminescence (PL) spectroscopy. The results indicate that the fluorescence properties of NSPs (20 ppm) were quenched upon Hg2+ addition in the range from 0 to 50 ppm. The studies demonstrated that NSPs acted as a potential host for Hg2+ ions compared to other interfering ions present in the seawater sample. The NSPs chemosensor provides a linearity range (5 – 1000 ppb) and limit of detection LOD (1 ppb; 5 nM), even below the values suggested by US EPA drinking water safety regulations, which indicates its potential utilization for mercury sensing in seawater environments.

The first electrochemical evaluation and voltammetric detection of the insecticide emamectin benzoate using an unmodified boron-doped diamond electrode

This study introduces for the first time an electroanalytical investigation and novel voltammetric method for the determination of emamectin benzoate (EB) using a cathodically pretreated boron-doped diamond electrode (CTP-BDDE). The CPT-BDDE electrode exhibited a well-defined irreversible signal at ∼1.35 V (vs. Ag/AgCl) using cyclic voltammetry. Different scan rates (from 10 to 750 mV s−1) suggested that the oxidation of EB on the BDDE surface is a diffusion-controlled process. Using square wave voltammetry, the anodic peak current was linear with EB concentrations from 0.25 mg L-1 to 12.5 mg L-1, with LOD and LOQ found to be 0.079 and 0.263 mg L-1, respectively. The effect of other insecticides used to treat sea lice and inorganic ions found in seawater on the voltammetric detection of EB was negligible. The proposed method was successfully applied to the determination of EB at different concentrations in real sea water samples. To the best of our knowledge, the voltammetric behaviour of EB and the electrochemical method for EB determination is reported for the first time.

Analytical Performance of Electromembranes as a Tool for Nanoconcentrations of Silver in Waters.

Electromembranes increase the efficiency of metal transport in liquid-phase microextraction systems by applying an electric potential, which accelerates the transport. Nevertheless, to get high extraction percentages in short extraction times it is necessary to take into account a great variety of factors, and multivariate optimization techniques are the best alternative to determine the most influential variables and to optimize the extraction process. In this work, a fractional factorial design was applied to determine the most influential variables in the extraction of silver by electromembranes. Thus, the effect of tri-isobutylphosphine sulphide (Cyanex 471x) concentration in the organic solution, sodium thiosulphate concentration in the acceptor solution, nitrate concentration in the sample solution, extraction time, stirring rate and electric potential on the enrichment factor were studied. Once the most important variables were selected, a small composite design (Draper-Lin) was used to obtain their optimal values to maximize the enrichment factor. Under these conditions, an experimental enrichment factor of 49.91 ± 3.95 was achieved after 22 min. Finally, the effect of saline matrix on the enrichment factor was tested and the optimized system was successfully applied to analyse silver concentrations at ultratrace levels, within the range of 7-29 ng·L-1 in different real seawater samples.

Ultra-sensitive simultaneous electrochemical detection of Zn(II), Cd(II) and Pb(II) based on the bismuth and graphdiyne film modified electrode

In this paper, a new dendritic bismuth and graphdiyne (Bi/GDY) film was fabricated on the surface of glassy carbon electrode (GCE) with a facile casting and electrodeposition procedure, which possessed significantly large active area, binding strength on electrode interface and fast electron transfer ability. The modified electrode was acted as an ultra-sensitive electrochemical sensor for individually and simultaneously assay of Zn(II), Cd(II) and Pb(II) by using differential pulse anodic stripping voltammetry (DPASV). As a result, the ultra-low detection limits (0.115 nM of Zn(II), 0.171 nM of Cd(II) and 0.146 nM of Pb(II), S/N = 3) and a wide linear concentration range from 10.0 nM to 100.0 μM were obtained. The constructed sensor exhibited excellent repeatability, reproducibility, stability and could be used to sensitive detect real seawater sample. The analytical results of Bi/GDY/GCE was further verified via atomic absorption spectroscopy. Therefore, Bi/GDY-based electrochemical sensor possesses great potentials for advanced applications in environment, biomedicine and food fields.

Fouling and Performance Investigation of Membrane Distillation at Elevated Recoveries for Seawater Desalination and Wastewater Reclamation.

This study reports on the impact of elevated recovery (i.e., 80%, 85%, and 90%) on the fouling and performance of air gap membrane distillation (AGMD) with real seawater and landfill leachate wastewater samples using polytetrafluoroethylene (PTFE) polymer membranes. Increasing the feed temperature from 55 °C to 65 °C improved the water flux of seawater and wastewater and shortened the operating time by 42.8% for all recoveries. The average water flux in the 80%, 85%, and 90% recovery experiments at the 65 °C feed temperature was 32%, 37.32%, and 36.7% higher than the case of 55 °C for the same recoveries. The water flux decline was more severe at a higher temperature and recovery. The highest flux decline was observed with a 90% recovery at 65 °C feed temperature, followed by an 85% recovery at 65 °C. Close examination of the foulants layer revealed that seawater formed a cake fouling layer made predominantly of metal oxides. In contrast, the landfill leachate fouling was a combination of pore blocking and cake formation, consisting mainly of carbonous and nitrogenous compounds. Physical cleaning with deionized (DI) water at 55 °C and 65 °C and chemical cleaning with hydrogen peroxide (H2O2) were investigated for their efficiency in removing membrane foulants. Analytical results revealed that seawater fouling caused membrane pore blockage while wastewater fouling formed a porous layer on the membrane surface. The results showed that membrane cleaning with hydrogen peroxide restored >97% of the water flux. Interestingly, the fouling factor in seawater tests was 10%, while it was 16% for the wastewater tests.

Flow-electrode capacitive deionization utilizing three-dimensional foam current collector for real seawater desalination

The three-dimensional (3D) carbon coated nickel foam was utilized as current collector in a flow-electrode capacitive deionization (CF-FCDI) device to strengthen the charge transfer ability of FCDI device, achieving distinguished desalination efficiency for real seawater. Utilizing 30 ppi carbon coated nickel foam as current collector with 12.5 wt% AC content at 1.2 V to treat 3.5 g L−1 NaCl solution, the CF-FCDI achieved 99.8% of salt removal efficiency (SRE), 3.29 µmol cm−2 min−1 of average salt removal rate (ASRR) and 97.0% of charge efficiency (CE), surpassing most desalination performances in previous reports. Compared with the titanium mesh (TM-FCDI) and graphite plate (GP-FCDI) current collector, the three-dimensional electric field and computational fluid dynamics (CFD) simulations demonstrated that 3D foam current collector has obvious stronger competitiveness. Its intrinsic 3D interconnected open-pore structure as flow channel and 3D electric field could not only enlarge the charge contact area between the current collector and flow-electrode, but also eliminate the restriction of 0.75 mm effective charging range within the carbon slurry in traditional serpentine flow channels. Finally, the excellent desalination performance of CF-FCDI device was also verified by treating simulated seawater, real seawater samples from Yellow Sea and South China Sea with a high SRE of 99.9%, 99.8%, and 99.9%, respectively. This work introduced a new strategy for enhancing charge transfer ability and overall desalination efficiency of FCDI device by utilizing a novel 3D foam-structured current collector for real seawater desalination.

A novel workflow for semi-quantification of emerging contaminants in environmental samples analyzed by LC-HRMS.

There is an increasing need for developing a strategy to quantify the newly identified substances in environmental samples, where there are not always reference standards available. The semi-quantitative analysis can assist risk assessment of chemicals and their environmental fate. In this study, a rigorously tested and system-independent semi-quantification workflow is proposed based on ionization efficiency measurement of emerging contaminants analyzed in liquid chromatography-high-resolution mass spectrometry. The quantitative structure-property relationship (QSPR)-based model was built to predict the ionization efficiency of unknown compounds which can be later used for their semi-quantification. The proposed semi-quantification method was applied and tested in real environmental seawater samples. All semi-quantification-related calculations can be performed online and free of access at http://trams.chem.uoa.gr/semiquantification/ .

A liquid micro-extraction based one-step method for the chemical fractionation of copper in seawater

In this work, the reagent Cyanex® 272 has been incorporated in a three-phase solvent bar micro-extraction system to selectively separate the inorganic and organic fractions of copper in seawater. Optimized conditions for micro-extraction of Cu fractions were 0.2 M Cyanex® 272 in the organic solution contained into the fiber pores, 0.5 M HCl as acceptor solution within the fiber, stirring rate of 500 rpm, and 60 min time of extraction, providing an enrichment factor of 51.6 ± 2.3. Experimental results for selective extraction of organic and inorganic Cu showed a good correlation with theoretical data for Cu speciation, and the relationship between enrichment factor and dissolved organic carbon (DOC) concentration in the samples was used to predict total Cu concentration. Instrumental determination of Cu presented a linear response within the range 0.1–20 µg L−1, obtaining a limit of detection of 0.03 µg L−1. Finally, the method was successfully applied to the study of Cu fractions in real seawater samples collected from the Bay of Cádiz (Spain).

Adsorptive removal of major and trace metal ions from synthetic saline and real seawater samples onto magnetic zeolite nanocomposite: application of multicomponent fixed-bed column adsorption

Adsorptive removal of major and trace metal ions from synthetic saline and real seawater samples onto magnetic zeolite nanocomposite: application of multicomponent fixed-bed column adsorption

Optical analog-signal transmission and retrieval through turbid water.

In this paper, we propose a new, to the best of our knowledge, and robust method to optically transmit analog signals in free space through turbid water. In the proposed method, each pixel of original signal is sequentially encoded into random amplitude-only patterns as information carrier. A single-pixel detector is utilized to collect light intensity at the receiving end. To verify feasibility and effectiveness of the proposed method, a number of optical experiments are carried out in different kinds of water conditions, e.g., clean water, water mixed with milk, water with salt, and water with salt and milk. In addition, real seawater samples are also tested. Experimental results demonstrate that the proposed method shows high robustness against different propagation distances through turbid water and resists the effect of various turbulence factors. The proposed method is applicable to transmit information with high fidelity and high robustness against light wave diffusion in free space through complex environment. Furthermore, the proposed method is easy to operate and is cost-effective, which could open up a novel insight into optical signal transmission in free space through turbid water.

Enzyme Method-Based Microfluidic Chip for the Rapid Detection of Copper Ions.

Metal ions in high concentrations can pollute the marine environment. Human activities and industrial pollution are the causes of Cu2+ contamination. Here, we report our discovery of an enzyme method-based microfluidic that can be used to rapidly detect Cu2+ in seawater. In this method, Cu2+ is reduced to Cu+ to inhibit horseradish peroxidase (HRP) activity, which then results in the color distortion of the reaction solution. The chip provides both naked eye and spectrophotometer modalities. Cu2+ concentrations have an ideal linear relationship, with absorbance values ranging from 3.91 nM to 256 μM. The proposed enzyme method-based microfluidic chip detects Cu2+ with a limit of detection (LOD) of 0.87 nM. Other common metal ions do not affect the operation of the chip. The successful detection of Cu2+ was achieved using three real seawater samples, verifying the ability of the chip in practical applications. Furthermore, the chip realizes the functions of two AND gates in series and has potential practical implementations in biochemical detection and biological computing.

Removal of Typical Volatile Organic Compounds in Condensed Freshwater by Activated Persulfate during Interfacial Solar Distillation

Recently, seawater desalination based on interfacial solar heating has attracted attention because of its environmental protection and high photothermal conversion efficiency. However, the high air–water interface temperature may cause freshwater quality safety risks because the volatile organic compounds (VOCs) in seawater are more likely to evaporate and condense into freshwater. In this work, typical VOCs (phenol) were prevented from entering into the condensed freshwater by using activated persulfate to take full advantage of interfacial solar distillation. The results showed that the addition of both peroxodisulfate (PDS) and peroxymonosulfate (PMS) could effectively reduce the concentration of phenol in condensed freshwater. The phenol’s distillation concentration rate (RD) was reduced from 74.4% to 14.3% with PMS and 20.5% with PDS. The Cl– was the main factor for activation of PMS, while carbon black, light, and heat were the main factors for activation of PDS. Meanwhile, PMS is better suited for removing VOCs due to its lower oxidant dosage and chlorinated disinfection byproducts compared with PDS. Finally, when real seawater samples were used as the source water for solar distillation, the water quality of typical indicators was lower than the limits set by Drinking Water Quality in China, US EPA, and WHO.

Sensitive detection of Pb ions by square wave anodic stripping voltammetry by using iron oxide nanoparticles decorated zinc oxide nanorods modified electrode

In this work, zinc oxide nanorods (ZnONRs) and Fe2O3 nanoparticles (Fe2O3NPs) were developed on indium tin oxide (ITO) as an Fe2O3NPs/ZnONRs/ITO electrode, and its performance for lead (Pb) ion detection in the aqueous phase was evaluated. Field-emission scanning electron spectroscopy (FESEM) and X-ray diffraction (XRD) were performed to determine the morphology and phases of the samples, respectively. Results confirmed the successful fabrication of the Fe2O3NPs/ZnONRs/ITO electrode. The FESEM and transmission electron microscopy (TEM) showed that the ZnONRs and Fe2O3NPs had diameters of 60–90 nm and ~17 nm, respectively. The performance of the Fe2O3NPs/ZnONRs/ITO electrode for Pb ions detection was evaluated using electrochemical analysis; cyclic voltammetry and square wave anodic peak voltammetry methods. The Fe2O3NPs/ZnONRs/ITO electrode showed the lowest limit of detection and sensitivity of 0.01 μM and 4.40 μA μM−1, respectively, within the linear dynamic range from 0.2 μM to 1.2 μM. The applicability of the Fe2O3NPs/ZnONRs/ITO electrode was tested using a real seawater sample. Results were comparable with those detected using inductively coupled plasma optical emission spectrometry, indicating the excellent performance of the Fe2O3NPs/ZnONRs/ITO electrode. The Fe2O3NPs/ZnONRs/ITO-modified electrode offers a cheap, fast, and simple detection for Pb ions.

Dispersive liquid–liquid microextraction of multi-elements in seawater followed by inductively coupled plasma-mass spectrometric analysis and evaluation of its greenness

A rapid and efficient dispersive liquid–liquid microextraction method was developed for the simultaneous extraction of V, Co, Ni, Cu, Zn, Se, Mo, Cd, and Pb in seawater samples prior to their determination by inductively coupled plasma-mass spectrometry. The factors affecting the DLLME, such as the volume of chelating reagent, types and volumes of dispersive and extraction solvents, and pH of the sample, were suitably optimized using a univariate approach. Under the optimum conditions, DLLME-ICP-MS exhibited a linear range of 0.1–100 µg/L for V, Co, Zn, Cd and 0.2–200 µg/L for Ni, Cu, Se, Mo, Pb, with coefficients of determination (R2) > 0.9978. The detection limits were in the range of 0.02–0.11 µg/L, and percentage relative standard deviations (%RSDs) were less than 8.7. The method showed good applicability for real seawater samples with relative recoveries ranging from 85 to 108%. Moreover, it is suitable for small volume samples, and it does not require any modification in the analytical instrument. Finally, the greenness of the proposed DLLME-ICP-MS method was evaluated using tools like Analytical Eco-Scale, Green Analytical Procedure Index, and Analytical Greenness Metric.

G-C3N4/MoS2 based floating solar still for clean water production by thermal/light activation of persulfate

Currently, seawater desalination based on air-water interface solar heating has triggered significant research interests because it effectively makes use of the solar energy and avoids fossil fuel consumption. However, to prevent the volatile organic compounds (VOCs) from volatilizing with water vapor which later will liquefy and enter the condensed freshwater is still a challenge. In this work, a g-C3N4/MoS2 based floating solar still (CM-FSS) combined with thermal/light activation of persulfate (PS) at air-water interface was applied for clean freshwater production for the first time. The CM-FSS was composed of a g-C3N4/MoS2 top layer for solar absorption, simultaneous thermal/light activation of PS and then VOCs degradation at air-water interface, a floating layer of expandable polyethylene (EPE) foam for heat isolation, and a transport channel of air-laid paper (ALP) for seawater and PS solution delivery. The water evaporation rate of the CM-FSS was measured at 1.23 kg m−2 h−1 under 1 kW m−2, which is 4.09 times higher than that of pure water without an evaporator. With the assistance of g-C3N4/MoS2 photocatalytic degradation and thermal/light activation of PS at the air-water interface, a high removal efficiency of a selected model VOCs pollutant of nitrobenzene (NB) could reach to 98.2% in condensed freshwater. Finally, when real seawater samples were employed as source water for solar distillation, the typical water-quality indices such as salinity, turbidity, anions, cations and organics of the condensed freshwater were below the limit values of the Standards for Drinking Water Quality in WHO, US EPA and China.

Green synthesis, characterization applications of iron oxide nanoparticles for antialgal and wastewater bioremediation using three brown algae

This study aims at controlling excess nutrients, including nitrogen and phosphorus, and harmful algae that pollute the marine environment using biosynthesized iron oxide nanoparticles. Aqueous extracts of brown seaweeds named Petalonia fascia, Colpomenia sinuosa, and Padina pavonica were selected for iron oxide nanoparticles' biosynthesis. The extracts were used as reductants of ferric chloride, and dark brown colors due to Fe3O4-NPs biosynthesis were observed. Iron signals were recorded in EDX spectra. FTIR analyses showed that the three algae extracts contained proteins and lipids that have the ability to proceed dual functions of bioreduction and stabilization of Fe3O4-NPs, suggesting that proteins in P. fascia, C. sinuosa, and P. pavonica extracts reduced FeCl3, and the aromatic compounds stabilized the biogenic Fe3O4-NPs. The biosynthesized Fe3O4-NPs via P. pavonica had the best nitrogen reduction percentage, followed by C. sinuosa and P. fascia for both concentrations 2 and 4 µg mL−1. The best results of phosphorus removal and Chlorophyll a (Chl a) reduction percentages using the Fe3O4-NPs concentrations were 2 and 4 µg mL−1 with nanoparticles synthesized via P. fascia and P. pavonica, respectively. The highest reduction in optical density for both 2 and 4 µg mL−1 was achieved by the nanoparticles synthesized by P. fascia. Novelty Statement Application of nanoparticles using seaweeds extracts could be alternative safe bioremediation of wastewaters. Currently, iron oxide nanoparticles are used to reduce nitrogen and phosphorus and reduce the blooming of harmful algae; little information about this issue has been reported. Such study also presented the anti-algal impacts of Fe3O4-NPs by tracing optical density and Chl a concentrations in the examined real seawater samples. Modern biotechnology to develop phytoremediation and seaweeds to enhance these remediation methods can be adopted.

Electrochemical determination of boron using the signal suppression of mannitol on a gold nanoparticle coated p-Aminothiophenol polymer electrode

In this study, a glassy carbon electrode (GCE) modified with gold nanoparticles (AuNPs) and coated with electropolymerized p-aminothiophenol (p-ATP) was used as a modified electrode (GC/AuNPs/PATP electrode) for the indirect electrochemical determination of boron (B) using boric acid-mannitol complexation. The developed electrode showed good electroactivity for B determination. Firstly the current intensity of mannitol was measured, then B (as H3BO3) was added to the medium and the unreacted mannitol was measured. The decrement in current intensity was recorded against B concentration to build linear calibration curves within the range of 5–50 mg L−1 of B using square wave voltammetry (SWV), and the oxidation peak potential of mannitol was observed at 0.97 V. The limit of detection (LOD) and limit of quantification (LOQ) were 1.43 mg L−1 and 4.77 mg L−1, respectively. Boron (5 mg L−1) was determined with quantitative recovery in the presence of 100-fold concentration (except 5-fold for Fe3+) levels of the potentially interferent ions (Cl−, SO42−, HCO3−, CO32−, NO32−, PO43−, NH4+, Cu2+, Mg2+, Ca2+, Na+, K+, Fe3+) in water using the proposed SWV method. Fe3+ and Cu2+ interferences could be overcome with cation exchange resin removal. Additionally, boron was determined in synthetic and real seawater samples. The proposed SWV method was statistically validated against the spectrophotometric carmine method using seawater, antibacterial hand sanitizer gel and boron/potassium nitrate (BPN) pyrotechnic formulation.

Plastic electrode decorated with polyhedral anion tetrabutylammonium octamolybdate [N(C4H9)4]4 Mo8O26 for nM phosphate electrochemical detection

Inorganic phosphorous (as phosphate (PO43−), is one of the essential nutrients for all living forms, either terrestrial or marine. In oligotrophic seawaters, this macronutrient is limited (10−9 M) and its ratio with other elements (nitrogen or carbon) is denoting the health state of the marine environment; a small variation of its concentration can produce eutrophication. The gold standard method used for PO43− detection is based on colorimetric detection of phosphomolybdate. The colored complex is obtained by mixing water-soluble molybdenum salts (Mo(VI)) and reducing agents in acid media, along with the sample containing PO43−. Moreover, the kinetic of complex formation is slow, about 1 h is generally required for color to develop, exposing the assay to the drawbacks of interferences as those from silica. The detection is preferably performed in a controlled environment (i.e. in a laboratory) because several chemicals and steps of preparations are required as well as the optical instrumentation is not intended for in-field use.Electrochemical sensors offer portability and simplicity making them a practical option for on-site detection applications. To gain an analytical alternative in measuring low quantities of PO43− (10−9 M), and overcome some of the drawbacks of the classical approaches, we optimised a new easy way to produce a plastic electrode decorated with an alkyl Mo-polyoxometalate (Mo8O264−), that is soluble in organic solvents. This tetra-butyl-ammonium octamolybdate powder, [N (C4H9)4]4 Mo8O26, purposely synthetized was identified with FTIR, Raman, MS methods, and the electroactivity and reactivity with PO43− was confirmed in solution with cyclic voltammetry (CV). When the Mo-decorated electrode was in contact with PO43−, an electroactive phosphomolybdate aggregate formed at the electrode surface that was electrochemically detectable with square wave voltammetry (SWV). A remarkably low detection limit of 6.1 nM, to PO43−, as well as good stability and selectivity were obtained also in real samples. In fact, PO43− was measured in saline simulated and real seawater samples at nM concentrations in less than 5 min. The present investigation provides a new alternative to the current standard colorimetric methods to detect low phosphate concentrations, showing the potential to be used for monitoring nutrients in oligotrophic seawater.

Analysis of environmental nanoplastics: Progress and challenges

Nanoplastics (<1000 nm) are gaining high attention worldwide as an emerging environmental contaminant because they are easier to be taken up by organisms and likely to pose higher ecological and health risks than microplastics (<5 mm). However, we are still lacking harmonized and reliable methodologies for analyzing nanoplastics in environments. Here, we reviewed 33 studies on state-of-art methodologies for pretreatment, separation, identification, and quantification of nanoplastics. Most of the studies successfully detected standard reference nanoplastics spiked in environmental samples but failed to separate and quantify nanoplastics from real field samples. Up to date, only five studies measured nanoplastics in real field samples, i.e., seawater, snow, air, sand, and agriculture soil samples, respectively. Raman spectroscopy and pyrolysis–gas chromatography/mass spectrometry (py-GC–MS) are the most popular analytical methods. However, the current spectroscopic methods are time-consuming and cannot cover the whole nano-range due to the detection limit of particle size; determination of the mass concentration of nanoplastics by the mass spectrometry methods are destructive, thus requiring extra/subsamples to obtain physical information of nanoplastics. The major caveat is that the quantification is often conducted without chemical confirmation of polymer types, raising concerns about the reliability of current results. It is also worth noting that recovery tests and blank controls, both of which are general steps in the quantification of conventional chemical pollutants, are rarely reported in nanoplastic studies. More efforts should be made to enhance the reliability and accuracy of nanoplastic analysis in environmental samples, which can only be achieved with strict chemical confirmation and adequate quality assurance along with the whole analytical process.

Copper film electrode for sensitive detection of nitrophenols

Abstract In this study, we present a copper film electrode (CuFE) for sensitive voltammetric detection of nitrophenols. The detection scheme comprised an electrochemical oxidative activation of a glassy carbon supporting electrode, an in situ formation of CuFE, and a measurement step. All three steps were performed simultaneously in a single cathodic voltammetric scan. Several critical parameters influencing the operation of CuFE were examined and optimized, such as the concentration of copper ions, pH, potential scan, activation time, etc. The CuFE showed excellent electroanalytical performance for the detection of selected mono-, di-, and trinitrophenols with good sensitivity in the low μg L−1 concentration range and favorable repeatability. The practical applicability of this sensor was successfully demonstrated by measuring 2,4-dinitrophenol, as a test analyte, in a real seawater sample.