Sodium Acetate Buffer Solution Research Articles

PH Determination of Acetic Acid-Sodium Acetate Buffer: An Application of Henderson-Hasselbalch Equation at Room Temperature

In article, we have reported the applying of Henderson-Hasselbalch equation in determination of pH of acetic acid and sodium acetate buffer solutions at about 298 Kelvin as room temperature. In preparation of these buffer solutions, we have taken 1.5 ml of glacial acetic acid into 100 ml of standard flask for making up 0.2M of acetic acid solution, and 0.64 gm of sodium acetate were dissolved into 100 ml distilled water. Now, we taken 36.2 ml prepared solution of sodium acetate into 100 ml of standard flask and added 14.8 ml of prepared acetic acid to make its volume 100 ml by using of distilled water, it is a buffer. In measuring of pH of prepared buffer solutions, we have been using a calibrated digital pen pH meter for accurate and quick reading. In observation, the pH of buffer solutions a quite fluctuation was appeared. But, it has gradually raised by adding small amount of basic 5N NaOH solution into buffer sample, and, an adjusted pH was being to 4.7 as well.

Changes in crystallinity of sago palm (Metroxylon sago spp.) waste during cellulose extraction

Changes in crystallinity of sago palm (Metroxylon sago spp.) waste during cellulose extraction

Ti3C2TxMXene modified indium tin oxide (ITO) electrode for electrochemical sensing of bilirubin based on a molecularly imprinted pyrrole polymer

In this study for the first time we are developing Ti3C2TxMXene-based molecularly imprinted electrochemical sensor for the detection of bilirubin (BR). Firstly, Ti3C2TxMXene is synthesized by chemical etching and deposited at the ITO electrode surface by drop casting. After that, pyrrole as a monomer is electropolymerized in the presence of a sodium acetate buffer solution containing the BR template to prepare a BR-imprinted electrode. The modification of ITO electrode with Ti3C2TxMXene has not only imparted binding properties to the substrate that are very important for MIP formation but has also rendered excellent electrochemical characteristics to the electrode as monitored by CV, DPV, and EIS techniques. The sensing studies have been performed with synthetic samples that reveal the potential of prepared molecular imprinted electrochemical sensors toward BR detection. The linearity range, limit of detection, and limit of quantification are calculated as 10 μM to 90 μM, 0.197 μM and 0.598 μM, respectively. Selectivity, stability, and reproducibility are also reported for the prepared MIP sensor.

Molecularly imprinted orthophenylenediamine with Ti3C2TxMXene‐based biosensor for sensitive detection of bilirubin

AbstractIn this study, bilirubin (BR) is detected by using a novel molecularly imprinted electrochemical sensor based on a Ti3C2TxMXene‐modified ITO electrode. First, Ti3C2TxMXene is synthesized by chemical etching and deposited at the ITO electrode surface by drop casting. After that, ortho‐phenylenediamine (o‐PD) as monomer is electropolymerized in the presence of a sodium acetate buffer solution containing the BR template to prepare BR‐imprinted electrode. Field emission scanning electron microscopy (FESEM), x‐ray diffraction and UV–visible absorption spectroscopy confirms the MXene synthesis. The molecular imprinted polymer (MIP) formation at the electrode is confirmed by electrochemical methods such as differential pulse voltammetry, electrochemical impedance spectroscopy, and cyclic voltammetry, and FESEM. The linearity range, limit of detection and the limit of quantification are calculated as 0.1 mg/dL to 20 mg/dL, 0.002 mg/dL, and 6.6 mg/dL respectively. Stability and reproducibility are also reported for the prepared MIP sensor.

Development and validation of synchronous spectrofluorimetric method for the simultaneous determination of duvelisib and moxifloxacin: greenness metric assessment and application to a pharmacokinetic study in rats

Duvelisib (DUV) is a potent anticancer drug whereas Moxifloxacin (MOX) is an antimicrobial drug with anti-proliferative potency against cancerous cells, which is empirically administered in cancer treatment. DUV and MOX combination is commonly prescribed to combat infections in patients while they are under chemotherapy treatment. This study describes, for the first time, the development of a simple and green synchronous spectrofluorimetric (SSF) method for the simultaneous estimation of DUV and MOX in plasma. DUV and MOX were quantified at 273 and 362 nm, respectively without interference between each other at Δλ of 120 nm. The experimental variables influencing fluorescence intensities were thoroughly investigated and the optimum conditions were established. At pH 3.5, the optimum synchronous fluorescence intensity (SFI) was achieved in water solvent by using sodium acetate buffer solution. Calibration curves for DUV and MOX, correlating the SFI with the corresponding drug concentration, were linear in the range of 50–1000 ng mL−1 for both drugs, with good correlation coefficients. The method was extremely sensitive, with limits of detection of 24 and 22 ng mL−1, and limits of quantitation of 40 and 45 ngmL−1 for DUV and MOX, respectively. The SSF method was validated according to the Food and Drug Administration (FDA) guidelines for validation of analytical procedures, and the validation parameters were acceptable. The proposed SSF method was applied to the pharmacokinetic and bioavailability studies in rats’ plasma after single concurrent oral administration of both drugs. The results of the study revealed that caution should be taken with DUV dose when concurrently administered with MOX. The greenness of SSF method was assessed by three different metric tools namely Analytical Eco-scale, Green Analytical Procedure Index, and Analytical Greenness Calculator. The results confirmed that SSF method is an eco-friendly and green analytical approach. In conclusion, the proposed SSF method is a valuable tool for pharmacokinetic/bioavailability studies and therapeutic drug monitoring of simultaneously administered DUV and MOX.

A centrifugal microfluidic platform for rapid detection of pathogens based on chitosan nucleic acid extraction and RAA-T7-CRISPR/Cas13a nucleic acid detection

This study reported a bacterial detection platform using chitosan electrostatic adsorption for nucleic acid purification, RAA-T7-CRISPR/Cas13a system for nucleic acid quantification and centrifugal microfluidic platform for full-automatic operation. First, the nucleic acids in the lysed bacterial sample were captured by chitosan modified in the microfluidic PDMS channel through electrostatic adsorption, followed by washing with sodium acetate buffer solution. Then, these captured nucleic acid templates were eluted using Tris-HCl buffer solution through restoring the electrical neutrality of chitosan. Finally, the eluted nucleic acid templates were transferred into the RAA-T7-CRISPR/Cas13a system and isothermally amplified at 37 °C, followed by real-time detection of fluorescent products. A centrifugal microfluidic chip was elaborately designed with a chitosan modified channel, eight functional chambers and three siphon valves to achieve sequential capture, washing, elution, amplification and detection of nucleic acids. This platform has the capacity of automatically detecting Salmonella within 1 h. The detection limit of this platform was 10 CFU/mL in chicken supernatant under the use of optimal conditions. The average recovery and standard deviation of this platform are 106.9% and 6.4%, respectively.

COPPER WHITLOCKITE SYNTHESIZED VIA HYDROTHERMAL TRANSFORMATION OF CALCIUM HYDROGEN PHOSPHATE DIHYDRATE

Metal ion substitution in calcium phosphate provides a vehicle for therapeutic delivery of metal ions at low cost and with a long shelf life. The whitlockite structure can incorporate metal ions, which enables the introduction of antibacterial and antiviral agents such as copper ions. The present study describes the synthesis of copper whitlockite (CuWH) via a single-step hydrothermal transformation of calcium hydrogen phosphate dihydrate in the presence of copper ions. Hexahedral morphology of single-phase CuWH was synthesized at 220 °C for 12 h at pH 2.0 in the presence of 5 to 7 mol% Cu2+ ions, suggesting that CuWH precipitation was both dose- and pH-dependent. The CuWH structure contained protonated phosphate, which also suggests that Cu2+ ions were incorporated not only into the Ca(5) site but also the Ca(4) site. The dissolution test mimicking a bioresorption environment created by osteoclasts showed similar dissolution characteristics of Ca2+ and Cu2+ ions in acetic acid–sodium acetate buffer solution containing potassium nitrate at pH 5.5.

Expired streptomycin as corrosion inhibitor for carbon steel in acetic acid - sodium acetate buffer solution

Corrosion inhibition of carbon steel in buffer acid solutions by expired streptomycin was studied by weight loss method, linear polarization, electrochemical impedance spectroscopy, as well as scanning electron microscopy. It was found that streptomycin reduces the metal corrosion rate, and the inhibition efficiency increases proportionally with the drug content. A high efficiency has been obtained for 10–3 M amount of inhibitor. Tafel polarization results indicate that the drug is active especially on the cathodic side and less on the anodic dissolution of iron reaction, acting as a mixed type corrosion inhibitor. The double layer capacitance of the metal - buffer solution interface, polarization resistance and film formation on the carbon steel surface have been emphasized by electrochemical impedance measurements. The scanning electron micrographs of the carbon steel samples in blank solutions have revealed a severe corrosion on the samples surface, while in the presence of the expired drug, the surface has remained almost unaffected. Electrochemical behavior of streptomycin has been also investigated by cyclic voltammetry.

Thermophysical studies of protonated and deprotonated glycine in aqueous sodium acetate buffer solutions at different temperatures

Interactions of glycine in water and in (0.10, 0.50 and 1.00) aqueous sodium acetate buffer solutions of pH (1.00 and 12.40) have been investigated at different temperatures, T/K = (298.15-318.15). Densities, and viscosities, of glycine in water and in aqueous sodium acetate buffer solutions have been measured. The obtained density data have been used to calculate apparent molar volume, , limiting partial molar volume, , limiting partial molar volumes of transfer, . Viscosity B-coefficient, viscosity B-coefficient of transfer, , Activation free energies per mole of the solute, and solvent, have been calculated from viscosity data. Further, second order derivative of partial molar expansion coefficient and dependence of coefficients on temperature is useful in measuring the structure making and breaking behavior of solute in these systems. Pair and triplet interaction coefficients for both the properties were also calculated. Thus, the results obtained from volumetric and viscometric studies are of considerable importance to identify different type of interactions (i.e. H-bonding, van der Waal’s interactions)in these systems.

Development and validation of a new stability indicating RP-UFLC method for the estimation of Bosentan

A new stability-indicating RP-UFLC method has been developed for the estimation of Bosentan in pharmaceutical dosage forms and the method was validated. Bosentan is used to lower the high blood pressure in lungs (pulmonary arterial hypertension). Bosentan acts by blocking the actions of endothelin -1and thereby lowers the blood pressure. Mobile phase mixture consisting of sodium acetate (pH 5.0) buffer solution and acetonitrile (50: 50 v/v) with flow rate 0.7 mL/min were the optimized chromatographic conditions (Detection wavelength 254 nm) for the present study. Linearity was observed in the concentration range of 0.1–100 μg/mL (R2 = 0.9998) with regression equation y = 126698 x – 392.49. The LOQ was found to be 0.08964 µg/mL and the LOD was found to be 0.02913 µg/mL. Stress degradation studies such as acidic, alkaline, oxidation, photolysis and thermal degradations were performed by exposing Bosentan and finally the proposed method was validated as per ICH guidelines. The assay of Bosentan was conducted by applying the proposed method to the marketed formulations. The proposed method is simple, specific, precise, and accurate and can be applied for the estimation of pharmaceutical formulations.

SIMULTANEOUS ESTIMATION OF CLONAZEPAM AND METRONIDAZOLE IN PHARMACEUTICAL TABLETS BY REVERSED-PHASE HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY MODE WITH UV DETECTION

Clonazepam (CLO) plays a significant role in treating seizures, myoclonic seizures, and other clinical infections, while metronidazole (MTZ) is an antiprotozoal, antibacterial drug. The reversed-phase high performance liquid chromatographic (RP-HPLC) technique has provided greater precision and sensitivity over other methods, especially the colorimetric and spectrophotometric. This study aimed to implement a simple method in pure and pharmaceutical tablets for the simultaneous determination of CLO and MTZ. The RPHPLC method's development and optimization for validating a separation method for the simultaneous estimation of both drugs in pharmaceutical formulation involved studying the optimum mobile phase, buffer concentration, and the pH value. Under the chromatographic conditions, RP-HPLC system achieved excellent separation on a Phenomenex HyperClone BDS (250 x 4.60 mm, 130A, and 5μ) at a temperature of 45°C and the following conditions: 65:35% acetonitrile:acetic acid and sodium acetate buffer solution (NaOAc/HAc) as mobile phase (pH 3.5); 20 μL injection volume at a flow rate of 0.75 mL/min and detection wavelength of 310 nm. The proposed RP-HPLC procedure demonstrated high precision (RSD% 1%), as well as the good linear relationship of the calibration graph at concentration ranges of 50-160, 35-100 ppb with a coefficient of determination (r2) of the regression line of 0.9996 and 0.9997 for metronidazole and clonazepam respectively. The proposed method offered excellent validated values for both LOD (4.24 and 3.06 ppb) and LOQ (14.15– 10.21 ppb) for both metronidazole and clonazepam drugs, respectively. The RP-HPLC method has been successfully applied to estimate metronidazole and clonazepam in the well-known commercial pharmaceutical tablets and gave an excellent recovery> 98% for both drugs. The results of the method was compared with the standard pharmacopeial method for both drugs using statistical tests, which indicated no difference in accuracy between the methods

Co-production bioethanol and xylooligosaccharides from sugarcane bagasse via autohydrolysis pretreatment

Autohydrolysis pretreatment is an effective, commercial and environmentally friendly processes for the co-production of bioethanol and xylooligosaccharides (XOS) from sugarcane bagasse (SCB). An XOS yield of 50.53% was obtained at 200 °C for 10 min by autohydrolysis pretreatment, most of cellulose and lignin remained in the solid residues, which can be converted into bioethanol. The ethanol yield (66.67%) in sodium acetate buffer solution (SAAB, pH 5.5) system was higher than that in the deionized water (DW) system (51.88%), because the stable pH regulated by the buffer was beneficial to maintain the cellulase and yeast activity. Moreover, the addition of non-ionic surfactants can effectively promote fermentation performances, especially with Tween 80, 82.28% ethanol yield (of the theoretical) was reached. The use of the buffer system and non-ionic surfactants provides an ideal strategy for ethanol production by fermentation of substrates with high lignin content. Therefore, this study shows a suitable and sustainable process for bioethanol and XOS production from SCB using autohydrolysis pretreatment as one-step of a biorefinery. • Autohydrolysis was an economical and feasible pretreatment method. • Bioethanol and XOS were co-produced from SCB via autohydrolysis pretreatment. • Buffer system was used for bioethanol production with high-lignin substrates. • Non-ionic surfactants can greatly increase fermentation performances. • 82.28% ethanol was produced from substrates with high lignin content.

The silicon availability in paddy soils as predicated by isothermal adsorption curve

Silicon (Si) is important for rice growth and development. Hence, it is urgent and necessary to evaluate the silicon availability of paddy soils. At present, the content of available silicon in soils is measured with 1 M acetic acid–sodium acetate (pH 4.0) buffer solution to estimate the silicon availability of paddy soils, whereas the method may not be used to evaluate silicon availability of paddy soils which are rich in calcium carbonate, or alkaline or applied with the slag. The sorption equation parameters for predicting the silicon availability of paddy soils are discussed. Isothermal adsorption with silicon equilibrium solutions (SiO2 content 0, 10, 20, 40, 60, 80, 100 mg L−1) and a pot experiment with rice plants (CK and Si treatments) were carried out with 18 paddy soils (0–20 cm) collected from major rice-producing areas in Liaoning Province of Northeast China to quantify the relationships between Si sorption parameters and soil silicon supply availability. The results showed that the equation y = bx − a could describe the Si sorption feature of 18 soils, and there were obvious differences in parameters a, b, and a/b of different soils. The y-axis intercept a of the isothermal adsorption curve linear equation indicates the content of exchangeable silicon in soils and can be used as an index representing soil silicon availability. The a value was significantly correlated with soil organic matter (OM), free iron oxide (Fed), activity of Fe oxides(Feo/Fed), and crystal/cement ratio ((Fed − Feo)/Feo), but not with pH. Parameters b and a/b were not significantly correlated with the soil physical and chemical properties. The relative silicon content (SiRE) and the relative yield of rice (YRE) increased with the a value, and the positive linear correlation between SiRE or YRE and a value reached significant p levels of 5% and 1% respectively. Isothermal adsorption equation parameter a can be used to predict the soil silicon availability, and silicon fertilizer could obviously improve the rice yield at a ≤ 126 mg kg−1 (SiO2).

Electronic coupling between molybdenum disulfide and gold nanoparticles to enhance the peroxidase activity for the colorimetric immunoassays of hydrogen peroxide and cancer cells

Peroxidase nanoenzymes exhibit a specific affinity toward substrates, thereby demonstrating application potential for realizing the colorimetric immunoassays of hydrogen peroxide (H2O2), which can be further used as a probe for imaging cancer cells. To enhance the intrinsic peroxidase activity of molybdenum sulfide (MoS2) nanomaterials, gold (Au) nanoparticles with an average diameter of approximately 2.1 nm were modified on a MoS2/carbon surface (denoted as MoS2/C-Au600) via ascorbic acid reduction. MoS2/C-Au600 can oxidize 3,3′,5,5′-tetramethylbenzidine (TMB) to generate a blue oxidation product in the presence of H2O2; this product exhibits peroxidase-like activities, superior to those of most existing MoS2-based nanoenzymes. Furthermore, MoS2/C-Au600 exhibits a high detection capability for H2O2 in the range of 1 × 10−5 to 2 × 10−4 mol/L (R2 = 0.99), and the lowest detection limit is 1.82 µmol/L in a sodium acetate and acetic acid buffer solution. Steady state kinetics studies indicate that the catalytic mechanism is consistent with the ping-pong mechanism. Given its strong absorption peak at 652 nm in the visible region, MoS2/C-Au600 can be used to image cancer cells due to the enhanced permeability and retention effect. Our findings demonstrate that the synergistic electronic coupling between multiple components can enhance the peroxidase activity, which can facilitate the development of an effective, facile, and reliable method to perform colorimetric immunoassays of H2O2 and cancer cells.

A metal-catex composite electrode for determination of paraquat in various samples by Ad-differential pulse cathodic stripping voltammetry

In this work, a novel kind of metal-catex composite electrode for determination of paraquat (PQ) by adsorptive differential pulse voltammetry is introduced. The metal-catex composite electrode was fabricated by cathodic electropolymerization of p-nitrophenol and p-nitrobenzoic acid in the presence of tin (II) chloride as a scaffold for composite structure on prepared glassy carbon electrode. Electropolymerization was carried out in sodium acetate medium. The surface of the fabricated electrode was characterized with field emission scanning electron microscope and energy-dispersive X-ray spectrometry. The obtained results show that there are Sn nanoparticles in the structure of the catex-composite. Chemical structure of metal-catex composite electrode was investigated using FTIR (ATR), 13C NMR, H NMR and a suitable mechanism for electropolymerization has been proposed. This metal-catex composite electrode was applied for determinations of PQ using sodium acetate buffer solutions at pH = 6.5 as an electrolyte solution. All parameters influencing the performance of the fabricated electrode were studied and optimized. The proposed electrode exhibits good linearity versus PQ concentration in the range of 3.8 × 10−8 to 7.7 × 10−7 mol L−1 and shows a manifold increase in sensitivity (more than 30 times) as compared to the glassy carbon electrode. The LOQ of this electrode was 7.78 × 10−9 mol L−1, which is comparable with that of other electrochemical methods. The mean, standard deviation and relative standard deviation for seven repetitive determinations of paraquat (7.78 × 10−8 mol L−1) were measured to be 7.75 × 10−8 mol L−1, ±0.29 × 10−8 mol L−1, and 3.75% respectively. This electrode was applied for the determination of paraquat in natural water, natural juice, potatoes and onions. The introduced electrode shows good stability with repeated use and over long periods (about 20 days). There is a good agreement between the results for water analysis by this method and the standard method.

Enzymatic Formation of Polyaniline, Polypyrrole, and Polythiophene Nanoparticles with Embedded Glucose Oxidase.

Polyaniline (PANI), polypyrrole (Ppy), and polythiophene (PTh) composite nanoparticles with embedded glucose oxidase (GOx) were formed by enzymatic polymerization of corresponding monomers (aniline, pyrrole, and thiophene). The influence of monomers concentration, the pH of solution, and the ratio of enzyme/substrate on the formation of PANI/GOx, Ppy/GOx, and PTh/GOx composite nanoparticles were spectrophotometrically investigated. The highest formation rate of PANI-, Ppy-, and PTh-based nanoparticles with embedded GOx was observed in the sodium acetate buffer solution, pH 6.0. The increase of optical absorbance at λmax = 440 nm, λmax = 460 nm, and λmax = 450 nm was exploited for the monitoring of PANI/GOx, Ppy/GOx and PTh/GOx formation, respectively. It was determined that the highest polymerization rate of PANI/GOx, Ppy/GOx, and PTh/GOx composite nanoparticles was achieved in solution containing 0.75 mg mL−1 of GOx and 0.05 mol L−1 of glucose. The influence of the enzymatic polymerization duration on the formation of PANI/GOx and Ppy/GOx composite nanoparticles was spectrophotometrically investigated. The most optimal duration for the enzymatic synthesis of PANI/GOx and Ppy/GOx composite nanoparticles was in the range of 48–96 h. It was determined that the diameter of formed PANI/GOx and Ppy/GOx composite nanoparticles depends on the duration of polymerization using dynamic light scattering technique (DLS), and it was in the range of 41–167 nm and 65–122 nm, when polymerization lasted from 16 to 120 h.

Fabrication of novel bone haemostasis sheet by using sugar-containing hydroxyapatite and plant-derived polymer.

The fabrication conditions of bone-haemostasis sheet were examined by using (i) phosphoryl oligosaccharides of calcium (POs-Ca), sugar-containing hydroxyapatite (s-Ca10(PO4)6(OH)2: s-HAp) derived from POs-Ca and (ii) natural plant-derived polymers (locust bean gum (LBG), guar gum (GG) and alginate (AG)). The sol, which had been prepared by dissolving 2 mass% LBG/GG and 2 mass% AG into 200 cm3 deionized water and then by agitating at the speed of 20 000 r.p.m., was immersed into 3 mass% POs-Ca solution at room temperature for 24 h; it was hydrothermally treated at 100°C for 5 h, and then freeze-dried at −50°C for 24 h to form porous composite sheet. The microscopic observation showed that the pore sizes were controlled in the range of 5–100 µm by the optimization of LBG/GG ratio. The composite sheet showed the noted uptake of simulated body fluid (1426%) at 37.0°C and also the human blood. Thus, the porous composite sheet was found to be a promising candidate of the bone haemostasis, on the basis of the data of haemostasis, uptake ability of SBF and solubility in acetic acid–sodium acetate buffer solution.

3D-architecture via self-assembly of Krebs-type polyoxometalate {[Na10(H2O)26][Sb2W20Zn2O70(H2O)6

A novel Krebs-type polyoxometalate [Na10(H2O)26][Sb2W20Zn2O70(H2O)6] {Zn2W2} (1) was fabricated from one-pot transformations of the trilacunary Keggin-type [B-α-SbW9O33]9− precursor, followed by Zn2+/Na+-assisted self-assembly of the Krebs-type polyanion. The {Zn2W2} polyanion was further self-assembled into 3D architecture with new topology by adjusting Na+ cations. The compound {Zn2W2} (1) was fully characterized with a wide range of analytical methods, including single crystal/powder X-ray diffraction, thermogravimetric analysis (TGA) and various spectroscopic techniques (FT-IR, Raman, UV–vis). Electrochemical performance of {Zn2W2} polyanion was also investigated by cyclic voltammetry (CV) in sodium acetate buffer solution. Moreover, compound {Zn2W2} (1) is an effective catalyst for the oxidation of cyclohexanol with hydrogen peroxide.

The chemo-enzymatic modification and degumming of hemp fiber by the laccase-2,2,6,6-tetramethylpiperidine-1-oxyl radical-hemicellulase system and physico-chemical properties of the products

In this study, we found an environmentally friendly system in the degumming of hemp fiber without using a strong acid and alkali. The chemo-enzymatic modification and degumming of hemp fiber used an acetic acid–sodium acetate buffer solution containing laccase, hemicellulase and 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) under a mild condition (pH = 5, T = 50℃). Through comparing and analyzing the physical and chemical properties of fiber products under different treatments, we found the method involving treatment with TEMPO/laccase/hemicellulase not only greatly removed most of the gum attached on the surface of the raw hemp fiber, but also introduced surface-active aldehyde and carboxyl groups into the fiber. The performances of the hemp fibers with different treatments were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction. We also found the product was finer, with a lower content of non-cellulosic components and it had better water uptake properties (moisture sorption and water retention value), which has potential application values in textile industries.

Electrochemical and structural characterization of Nafion/Bismuth-Tin nanocomposites stabilized with polyoxyethylene 23 lauryl ether (Brij)

Nafion/Bismuth-Tin nanocomposites stabilized with polyoxyethylene 23 lauryl ether (brij) were produced in a mixture of nafion and brij dissolved in N-N dimethylformamide. Metal salts were reduced in the presence of sodium borohydride assisted by ultrasound. The average hydrodynamic diameter of polymer-metal particles was measured via dynamic light scattering (DLS) and related to the composition of the reactive mixture; growth kinetics were compared with the Liftshitz-Sloyozov-Wagner model, and we found that the polymer-tin system of nanoparticles was time stable and that the size of the nanoparticles, close to 100 nm, is not dependent on brij concentration. The selected nanocomposites with a total metal concentration of 13% w/w were structurally characterized by means of infrared (IR) and X-ray photoelectron spectroscopy (XPS). Furthermore, the morphology and phase-metal distribution was studied via electron microscopy (SEM and TEM). The nanocomposites were used as electrodes for cadmium detection through square-wave anodic stripping voltammetry (SWASV) in a sodium acetate buffer solution. The materials with higher bismuth content allowed obtaining better results in terms of the peak current; however, the addition of tin up to 50% allows producing material with greater resistance to oxidation.