Porous Platinum Research Articles

Highly porous Pt3Ni nanosheets for enhanced hydrogen evolution reaction

Two-dimensional (2D) nanosheets with high surface-to-volume ratios have garnered significant attention for their electrocatalytic properties. This study explores the characterization and electrocatalytic performance of highly porous monometallic platinum (Pt) nanosheets and bimetallic platinum-nickel (Pt3Ni) nanosheets for the hydrogen evolution reaction (HER) in both alkaline and acidic media. Advanced characterization techniques were employed to elucidate the morphological and compositional properties of the Pt and Pt3Ni nanosheets. Electrochemical characterization demonstrated that Pt3Ni nanosheets/C outperformed Pt nanosheets/C and commercial Pt/C in terms of HER activity and stability. The enhanced HER performance of Pt3Ni nanosheets/C is believed to be due to the dominance of the Volmer-Tafel mechanism. These findings highlight the potential of 2D bimetallic nanosheets and suggest a promising avenue for advancing hydrogen energy technologies.

Simple and Ultrasensitive Nanozyme-Linked Immunosorbent Assay for SARS-CoV-2 Detection on a Syringe-Driven Filtration Device.

This work proposed a simple and ultrasensitive nanozyme-based immunoassay on a filtration device for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid protein (NP). Gold core porous platinum shell nanoparticles (Au@Pt NPs) were synthesized with high catalytic activity to oxidize 3,3',5,5'-tetramethylbenzidine, leading to an oblivious color change. The filtration device was designed based on the size difference of magnetic beads, filter membrane pore, and Au@Pt NPs. A simple, rapid, and consistent washing procedure can be performed with the help of a plastic syringe. This detection method could realize the quantitative detection of SARS-CoV-2 NP within 80 min for point-of-care needs. The limit of detection for the SARS-CoV-2 antigen was 0.01 ng/mL in buffer. The coefficients of variation of the assay were 1.78% for 10 ng/mL SARS-CoV-2 antigen, 2.03% for 1 ng/mL SARS-CoV-2 antigen, and 2.34% for the negative sample, respectively. The specificity of the detection platform was verified by the detection of various respiratory viruses. This simple and effective detection system was expected to promote substantial progress in the development and application of virus immunodetection technology.

Smartphone-enabled flow injection amperometric glucose monitoring based on a screen-printed carbon electrode modified with PEDOT@PB and a GOx@PPtNPs@MWCNTs nanocomposite

This study presents a modified screen-printed carbon electrode (SPCE) to determine glucose in a custom-built flow injection system. The biosensor was constructed by immobilizing glucose oxidase on porous platinum nanoparticles decorated on multi-walled carbon nanotubes (GOx@PPtNPs@MWCTNs). The fabrication of the biosensor was completed by coating the GOx@PPtNPs@MWCTNs nanocomposite on an SPCE modified with a nanocomposite of poly(3,4-ethylenedioxythiophene) and Prussian blue (GOx@PPtNPs@MWCTNs/PEDOT@PB/SPCE). The fabricated electrode accurately measured hydrogen peroxide (H2O2), the byproduct of the GOx-catalyzed oxidation of glucose, and was then applied as a glucose biosensor. The glucose response was amperometrically determined from the PB-mediated reduction of H2O2 at an applied potential of −0.10 V in a flow injection system. Under optimal conditions, the developed biosensor produced a linear range from 2.50 μM to 1.250 mM, a limit of detection of 2.50 μM, operational stability over 500 sample injections, and good selectivity. The proposed biosensor determined glucose in human plasma samples, achieving recoveries and results that agreed with the hexokinase-spectrophotometric method (P > 0.05). Combining the proposed biosensor with the custom-built sample feed, a portable potentiostat and a smartphone, enabled on-site glucose monitoring.

Exploring Enhanced Hydrolytic Dehydrogenation of Ammonia Borane with Porous Graphene-Supported Platinum Catalysts.

Graphene is a good support for immobilizing catalysts, due to its large theoretical specific surface area and high electric conductivity. Solid chemical converted graphene, in a form with multiple layers, decreases the practical specific surface area. Building pores in graphene can increase specific surface area and provide anchor sites for catalysts. In this study, we have prepared porous graphene (PG) via the process of equilibrium precipitation followed by carbothermal reduction of ZnO. During the equilibrium precipitation process, hydrolyzed N,N-dimethylformamide sluggishly generates hydroxyl groups which transform Zn2+ into amorphous ZnO nanodots anchored on reduced graphene oxide. After carbothermal reduction of zinc oxide, micropores are formed in PG. When the Zn2+ feeding amount is 0.12 mmol, the average size of the Pt nanoparticles on PG in the catalyst is 7.25 nm. The resulting Pt/PG exhibited the highest turnover frequency of 511.6 min-1 for ammonia borane hydrolysis, which is 2.43 times that for Pt on graphene without the addition of Zn2+. Therefore, PG treated via equilibrium precipitation and subsequent carbothermal reduction can serve as an effective support for the catalytic hydrolysis of ammonia borane.

Self-enhanced nanohydrogel electrochemiluminescence biosensor based on CRISPR/Cas12a and gold platinum nanoparticles modification for high-sensitivity detection of Burkholderia pseudomallei

The simple, rapid, and accurate detection of highly lethal melioidosis is crucial for early clinical diagnosis and improving cure rates. Currently, due to time consumption, low sensitivity and detection rate the existing clinical detection methods cannot satisfy the needs of clinical diagnosis. Herein, a novel self-enhanced porous hydrogel material (Au@PEI-ABEI@Pt) for ultrasensitive ECL strategy of detection B. pseudomallei was report. The novel porous hydrogel material composed of PEI-ABEI porous hydrogel, gold nanoparticles (AuNP) and platinum nanoparticles (PtNP) have large specific surface area and porous structure, which not only fix more ABEI to realize self-enhanced ECL signal amplification, but also facilitate ion diffusion and efficient utilization of catalytic materials, realizing rapid electron transfer and zero-distance catalysis, significantly improving the initial signal of ECL sensor. Moreover, the most attractive aspect is that Au@PEI-ABEI@Pt hydrogels with good biocompatibility can achieve widespread application of CRISPR/Cas12a in solid-phase carriers without affecting the sensitivity, specificity and shearing activity of CRISPR/Cas12a. After coupling with the ECL system and CRISPR/Cas12a signal amplification strategy, the Au@PEI-ABEI@Pt can achieve an ultrasensitive ECL assay of B. pseudomallei with the LOD of 5 CFU mL−1 in complex samples, with high specificity and stability to effectively classify B. pseudomallei and other Gram-negative bacteria. This study shows that the developed porous hydrogel materials not only serve as an excellent ECL signal reporter to significantly improve the detection sensitivity of ECL biosensors, but also provide a new approach for the wide application of CRISPR/Cas systems in solid-phase carriers.

Boron-alloyed porous network platinum nanospheres for efficient oxygen reduction in proton exchange membrane fuel cells

Alloying (or doping) non-metals with platinum (Pt) is an advanced solution for the development of high-performance Pt-based electrocatalysts for oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs). Herein, we report boron (B)-alloyed Pt nanospheres (B-PtNSs) with a porous network nanostructure by a combination strategy of confinement reduction and post-boronation. B-alloying can induce effective electronic/geometric structures, strong Pt-B coordination, and lowered d-band center to weaken the binding energy of oxygenated intermediates on the Pt surface. The H2-O2 PEMFC with such a B-PtNSs/C as the cathode catalyst can reach a maximum power density of 1.49 W cm−2, about 1.28 times higher than that of Pt/C. After 30,000 voltage cycles in the range of 0.6 ∼ 0.95 V, only a 14.1 % loss of initial peak power density can be observed, while that with Pt/C declines 45.7 %. Non-metals alloying with Pt-based nanostructures can enable high-performance ORR electrocatalysts for their practical application in PEMFCs.

Predicting Lifetime and Reliability of Porous Platinum Electrodes in Solid-State Electrolyte Sensors: An Atomic Anharmonic Theory Approach

Predicting Lifetime and Reliability of Porous Platinum Electrodes in Solid-State Electrolyte Sensors: An Atomic Anharmonic Theory Approach

One-step paper-based SlipChip for the sensitive detection of C-reactive protein with porous platinum nanozyme-assisted signal amplification

The development of efficient and sensitive point-of-care testing is crucial for preparedness in the post-pandemic era. Although paper-based lateral flow assays have attracted attention and have various advantages for rapid, on-site diagnosis, they have low sensitivity. To overcome the limitations of the existing assays, in this study, we aimed to develop a new, one-step, nanozyme-amplified SlipChip for the sensitive detection of C-reactive protein (CRP). The SlipChip was constructed by combining wax-printed paper with different channel designs. The three-dimensional (3D) fluidic configuration of the SlipChip allowed for the sequential delivery of reagents, enabling mixing and signal amplification with a one-step sliding operation. As a signal-amplifying reagent, peroxidase-mimicking porous platinum nanozyme (pPtNZ) was synthesized using a simple wet chemical method. The pPtNZ conjugated on the test line catalyzes the oxidation of diaminobenzidine (DAB) in the presence of hydrogen peroxide, increasing the color intensity. The immunoassay results of the SlipChip were easily interpreted within 20 min, and the color intensity was visually enhanced by DAB precipitation over time, resulting in up to 6-fold signal amplification. The proposed pPtNZ-SlipChip exhibited high analytical performances for the one-step detection of serum and salivary CRP from 0.1 to 1000 ng/mL, with a limit of detection of 0.03 ng/mL. These results revealed the potential and applicability of the pPtNZ-SlipChip, with the advantages of simplicity, sensitivity, low cost, and portability for on-site detection and point-of-care testing.

Pore Forming Agent–Assisted Fabrication of Porous Platinum Vent Frits and Their Suitability Evaluation for Radioisotope Power Sources

Disc-shaped porous platinum sintered frits were fabricated employing a pore forming agent (PFA) via a powder-metallurgical process. Porous vent frits using several platinum-PFA compositions were prepared after characterizing the starting materials (platinum and PFA powders) for particle size (D50) and distribution (D10 to D90), morphology, Brunauer-Emmet-Teller surface area, density (apparent and tap), etc. The sintered platinum vent frits were extensively characterized to evaluate their suitability for application in terms of surface microstructure analysis by scanning electron microscopy, helium/air permeability parameters, and particulate filtration characteristics. This paper reports for the first time on the measurement of retention efficiency of vent frits for particulate sizes 0.3, 0.5, and 1 µm. The platinum frits made using 10 and 20 vol % PFA were found to be suitable as a vent hole filter for radioisotope power sources.

Glucose Electrocatalysis of Multi-walled Carbon Nanotubes/Polyvinyl Alcohol Conducting Hydrogel Composite Platinum Electrode

A porous conductive hydrogel electrode film of multi-walled carbon nanotubes (MWCNTs)/polyvinyl alcohol (PVA) was prepared by electrophoretic deposition technology, and the selective catalytic ability of MWCNTs/PVA on glucose was verified by cyclic voltammetry and open-circuit voltage. The electrochemical and physicochemical properties of MWCNTs/PVA porous conductive hydrogel electrode films were also characterized. The synergistic catalytic effects of MWCNTs/PVA porous conductive hydrogel electrode films and platinum electrode on the electrochemical oxidation of glucose in different PH solutions were studied.

Paired electrochemical synthesis of formate via oxidation of glycerol and reduction of CO2 in a flow cell reactor

The conventional anodic oxygen evolution (OER) in electrochemical CO2 reduction (CO2R) needs to be replaced as it accounts for a major share in energy consumption while being a product of little to no value. In this work, we replace OER by glycerol oxidation reaction (GOR) to synthesize products such as formate, lactate and glycolate. Hereby, for the first time, GOR was successfully paired with cathodic CO2R to formate in a flow reactor at a significant current density of 50 mA/cm2 producing value added anode products with a simultaneously reduced cell voltage. Using a porous platinum anode, GOR reduced the anode potential as well as cell potential by ∼1 V compared to OER. We report an anodic Faraday efficiency (FE) of 30% to ∼53% for liquid products, of which lactate dominates. The structure of the electrode has a significant impact on the dominant product as mainly formate is synthesized on a planar electrode, where the cummulated FE for all liquid products is up to 76%. The concurrent FE to formate at cathode and anode reached a values of up to 74% and 30% respectively and 66% and 76%, respectively, considering all value-added products. By successfully pairing GOR with CO2R in a flow cell reactor, this work marks an important step towards energy-efficient and economically viable processes.

EGFR-antagonistic affibody-functionalized Pt-based nanozyme for enhanced tumor radiotherapy

Clinical radiotherapy (RT) is severely limited by hypoxic tumor microenvironment and a lack of targeting precision. Therefore, it is crucial to develop highly efficient radiosensitizers to enhance RT efficacy. Herein, a novel kind of epidermal growth factor receptor (EGFR)-antagonistic affibody-functionalized Pt-based nanozyme for RT sensitization to EGFR-positive tumors was developed. In this study, porous platinum nanoparticles (pPt NPs) featuring catalase (CAT)-like activity and strong radiation energy absorption ability were first synthesized. Then, a thin biomimetic polydopamine (PDA) layer was coated on pPt NPs to optimize its biocompatibility as well as provide a reactive surface. Finally, a dimeric EGFR-antagonistic affibody called ZEGFR expressed by the Escherichia coli (E. coli), was conjugated to pPt@PDA NPs (termed pPt@PDA-ZEGFR NPs) to precisely recognize EGFR-positive A431 tumors. Under the navigation of ZEGFR, superior tumor homing was achieved with these Pt-based nanozymes, which was ascribed to EGFR receptor-mediated endocytosis. As high-Z metal NPs exhibit an inherently strong ability to absorb radiation energy and catalyze endogenous H2O2 in tumors, the pPt@PDA-ZEGFR NPs demonstrated superb therapeutic efficacy; specifically, the NPs significantly inhibited HIF-1α expression and increased RT-induced DNA damage. Furthermore, the biosafety of these Pt-based nanozymes was good during short-term treatment. In summary, EGFR-antagonistic affibody-functionalized Pt-based nanozymes are promising radiosensitizers for the precise therapy of EGFR-positive tumors.

Electrochemical decarboxylation of acetic acid on boron-doped diamond and platinum-functionalised electrodes for pyrolysis-oil treatment.

Electrochemical decarboxylation of acetic acid on boron-doped-diamond (BDD) electrodes was studied as a possible means to decrease the acidity of pyrolysis oil. It is shown that decarboxylation occurs without the competitive oxygen evolution reaction (OER) on BDD electrodes to form methanol and methyl acetate by consecutive reaction of hydroxyl radicals with acetic acid. The performance is little affected by the applied current density (and associated potential), concentration, and the pH of the solution. At current densities above 50 mA cm-2, faradaic efficiencies (FEs) of 90% towards the decarboxylation products are obtained, confirmed by in situ electrochemical mass spectrometry (ECMS) investigation showing only small amounts of oxygen formed by water oxidation. Using platinum-modified BDD electrodes, it is shown that selectivity to ethane, the Kolbe product, strongly depends on the shape and geometry of the platinum particles. Using nano-thorn-like Pt particles, a faradaic efficiency of approx. 40% towards ethane can be obtained, whereas 3D porous platinum nanoparticles showed high selectivity towards the OER. Using thin platinum layers, a high FE of >70% towards ethane was obtained, which is thickness-independent at layer thicknesses above 20 nm. Comparison with other substrates revealed that BDD is an ideal support for Pt functionalisation, giving advantages of stability and high-value-product formation (ethane and methanol). In short, this work provides guidelines for electrode fabrication in the context of the electrochemical upgrading of biomass feedstocks by acid decarboxylation.

Methanol Synthesis from CO2 and H2O Using a Solid Phosphate Electrolyzer at 240 °C and 28 Bar

It has been demonstrated that it is possible to produce methanol in one step in reasonable amounts by electrolysis of CO2 and H2O gasses dissolved under 28 bar and at 240 °C in contact with an electrolyte consisting of solid CsH2PO4 with additions of polyvinyl butyral (PVB) acting as a binder. The cathode was designed as a sandwich with a layer of a copper methanol catalyst and a porous platinum electrode. The anode consisted of porous ruthenium metal covered by a layer of RuO2. The system was operated with current densities of up to ca. 100 mA cm−2 with a voltage of less than 2 volts producing methanol with a Faradaic efficiency of up to ca. 7%. There seems to be nothing against recirculating the rest of reactant gases to improve the conversion. The question is of course whether the present approach can compete with a more traditional conversion starting with electrochemical produced hydrogen.

A Porous Bimetallic Au@Pt Core-Shell Oxygen Generator to Enhance Hypoxia-Dampened Tumor Chemotherapy Synergized with NIR-II Photothermal Therapy.

The characteristic hypoxia of solid tumors and inadequate oxygen supply become a key causation of the resistance to chemotherapy in cancer treatment. Herein, a bimetallic oxygen nanogenerator, i.e., porous Au@Pt core-shell nanostructures, is particularly developed to reduce the multidrug resistance by oxygenating the tumor along with synergistic chemo-photothermal therapy for efficient tumor eradication. The porous platinum (Pt) shell was able to catalyze oxygen generation from endogenous hydrogen peroxide in the tumor, reducing the exocytosis of doxorubicin (DOX) via suppressed expression of hypoxia-inducible factor-1α, multidrug resistance gene 1, and P-glycoprotein. The strong absorbance of Au@Pt nanostructures in NIR window II enabled NIR-II photothermal therapy. Further incorporation of DOX into the mesopores of Au@Pt nanostructures with the assistance of phase change materials (PCM) led to the formulation of Au@Pt-DOX-PCM-PEG nanotherapeutics for NIR-II-activated chemotherapy. This work presents an efficient H2O2-driven oxygenerator for enhanced hypoxia-dampened chemotherapy and NIR-II photothermal therapy.

Electrochemical biosensor with aptamer/porous platinum nanoparticle on round-type micro-gap electrode for saxitoxin detection in fresh water

Cyanotoxins are toxins produced by cyanobacteria; they negatively impact water resources used by humans and disrupt ecosystems worldwide. Among cyanotoxins, saxitoxin (STX) is a small molecule that causes paralysis in humans and contamination in freshwater resources. To monitor low concentration of STX levels, a sensitive and high fidelity detection system is required. In this study, a round-type micro-gap electrode (RMGE) was fabricated that provides the high signal fidelity for STX detection in real freshwater sample. The RMGE has the 15 pairs of identical electrode wire length between gap that gives the high signal fidelity. In addition, the sensitivity for STX detection was improved by introducing the porous platinum nanoparticle (pPtNP) that enahced the electrochemical sensitivity and the STX aptamer was used as the bioprobe. An electrochemical measurement method (square wave voltammetry (SWV) and electrochemical impedance spectroscopy (EIS)) was introduced to construct STX biosensor. To evaluate the biosensor performance, the limit of detection (LOD) and selectivity test were performed on real freshwater samples. The biosensor demonstrated high selectivity even in freshwater samples over a wide linear concentration range of 10 pg/mL to 1 μg/mL and a detection limit of 4.669 pg/mL. These results suggest that the designed biosensor shows a wide range of possibilities for the detection of toxicants in freshwater that provide the new direction to the biosensor electrode design.

Sensitive Electrochemical Non-Enzymatic Detection of Glucose Based on Wireless Data Transmission.

Miniaturization and wireless continuous glucose monitoring are key factors for the successful management of diabetes. Electrochemical sensors are very versatile and can be easily miniaturized for wireless glucose monitoring. The authors report a microneedle-based enzyme-free electrochemical wireless sensor for painless and continuous glucose monitoring. The microneedles (MNs) fabricated consist of a 3 × 5 sharp and stainless-steel electrode array configuration. Each MN in the 3 × 5 array has 575 µm × 150 µm in height and width, respectively. A glucose-catalyzing layer, porous platinum black, was electrochemically deposited on the tips of the MNs by applying a fixed cathodic current of 2.5 mA cm−2 for a period of 200 s. For the non-interference glucose sensing, the platinum (Pt)-black-coated MN was carefully packaged into a biocompatible ionomer, nafion. The surface morphologies of the bare and modified MNs were studied using field-emission scanning electron microscopy (FESEM) and energy-dispersive X-ray analysis (EDX). The wireless glucose sensor displayed a broad linear range of glucose (1→30 mM), a good sensitivity and higher detection limit of 145.33 μA mM−1 cm−2 and 480 μM, respectively, with bare AuMN as a counter electrode. However, the wireless device showed an improved sensitivity and enhanced detection limit of 445.75, 165.83 μA mM−1 cm−2 and 268 μM, respectively, with the Pt-black-modified MN as a counter electrode. The sensor also exhibited a very good response time (2 s) and a limited interference effect on the detection of glucose in the presence of other electroactive oxidizing species, indicating a very fast and interference-free chronoamperometric response.

Wet-Chemical Synthesis of Porous Multifaceted Platinum Nanoparticles for Oxygen Reduction and Methanol Oxidation Reactions

Herein, we report a facile and flexible synthesis of porous and highly faceted platinum nanoparticles (NPs) performed in the liquid phase. The synthesis is performed by reduction of platinum 2,4-pentantedionate in the presence of oleylamine and oleic acid in dibenzyl ether at 200 °C. The growth process was monitored by time-course transmission electron microscopy (TEM), revealing a peculiar progressive evolution that, in comparison with previous methodologies, is quite unusual. In fact, the morphology evolves first through nanocubes, nanostars, and dendrites to arrive at porous multifaceted NPs. This offers the possibility to selectively obtain materials with different degrees of complexity at a different time of reaction with one synthetic approach. Moreover, fine tuning of the reaction conditions was achieved by assessing, in dedicated experiments, the effects of temperature, surfactant concentration, and surfactant ratio, allowing control on NPs’ dispersity and shape reproducibility. The dimensionally monodispersed NPs have a mean diameter of 52 ± 2 nm and display small regular crystallites with uniform facets exposed on the surface as evinced by high-resolution-TEM analysis. The as-prepared multifaceted platinum NPs were tested for oxygen reduction and methanol oxidation reactions exhibiting improved catalytic activity with respect to conventional Pt-based nanomaterials.

Physiochemical Role of Nanoparticles in Solid Fuel Cells, Production and Applications in Physics and Chemical Sciences

Demand of fuel cells have been increased due to the high potential and incredibly efficient power sources. They have been wide range of applications such as portable fuel cells in laptops, up to huge stationary installations to power data centers. Ordinary cells are not providing good reliability and quality of power while on the other hand, fuel cells with efficient metal body allows the good reliability and quality of power provided does not degrade over time. Fuels cell that comprised of carbon nanotubes have been efficiently used for the fabrication process due to fine catalysis of adoption major barrier to many applications for power generation for commercial, industrial and residential buildings and in remote or inaccessible areas. The carbon-nanotubes are made up of smaller particles of carbon with allow the network of fine fibers while on the other hand, ordinary cells can be designed in storing hydrogen, as per the requirements. Porous Platinum nanotubes nanoporous have been designed to adopt the porosity and flow of the carbon particles for generation of energy. Different oxidants can be employed for fuel adjustments and other site reactions but oxygen is preferable due to their availability. It is easy to maintain the fuel cells adjustment through the use of nanotechnology to the industrials processes for manufacturing of variety of new materials.

Simultaneous detection of hesperidin and narirutin in residual water using nanoporous platinum electrosynthesized by alloying-dealloying mechanism

• An electrochemical sensor for the simultaneous determination of HES and NAR was performed. • 3D nanostructured porous platinum was electrosynthesized on the electrode surface. • 3DnpPt-SPE showed electrocatalytic current for HES and NAR oxidation. • The detection of HES and NAR in wastewater from citrus industry could be achieved. This paper reports the versatile preparation of three-dimensional nanostructured porous platinum (3DnpPt) directly on the surface of a screen-printed electrode via a simple electrochemical method and its application for the simultaneous voltammetric determination of hesperidin (HES) and narirutin (NAR) in residual water from the citrus industry. The surface morphology of the electrode was characterized by field-emission scanning electron microscopy (FEG-SEM), electron diffraction X-ray (EDX), X-ray photoelectron spectroscopy (XPS), and by the electrochemical impedance spectroscopic (EIS) technique. The results obtained from the voltammetric studies conducted showed that the sensor has good electrocatalytic activity and selectivity for HES and NAR oxidation. The linear scanning voltammetry (LSV) technique employed yielded linear ranges of 10 µmol L −1 to 0.4 mmol L −1 and 10 µmol L −1 to 0.5 mmol L −1 , with detection limits of 6.61 µmol L −1 and 0.21 µmol L −1 , and amperometric sensitivity of 0.52 A L mol −1 and 0.79 A L mol −1 for HES and NAR, respectively. The proposed 3DnpPt-SPE sensor also exhibited good repeatability and high selectivity, as well as long-term stability. The sensor was successfully applied in residual water sample for the simultaneous quantification of HES and NAR where good recovery rates were obtained.