Tetradodecylammonium Bromide Research Articles

Electrical Properties of Taste Sensors with Positively Charged Lipid Membranes Composed of Amines and Ammonium Salts.

Currently, taste sensors utilizing lipid polymer membranes are utilized to assess the taste of food products quantitatively. During this process, it is crucial to identify and quantify basic tastes, e.g., sourness and sweetness, while ensuring that there is no response to tasteless substances. For instance, suppression of responses to anions, like tasteless NO3- ions contained in vegetables, is essential. However, systematic electrochemical investigations have not been made to achieve this goal. In this study, we fabricated three positively charged lipid polymer membranes containing oleylamine (OAm), trioctylemethylammonium chloride (TOMACl), or tetradodecylammonium bromide (TDAB) as lipids, and sensors that consist of these membranes to investigate the potential change characteristics of these sensors in solutions containing different anions (F-, Cl-, Br-, NO3-, I-). The ability of each anion solution to reduce the positive charge on membranes and shift the membrane potential in the negative direction was in the following order: I- > NO3- > Br- > Cl- > F-. This order well reflected the order of size of the hydrated ions, related to their hydration energy. Additionally, the OAm sensor displayed low ion selectivity, whereas the TOMACl and TDAB sensors showed high ion selectivity related to the OAm sensor. Such features in ion selectivity are suggested to be due to the variation in positive charge with the pH of the environment and packing density of the OAm molecule in the case of the OAm sensor and due to the strong and constant positive charge created by complete ionization of lipids in the case of TOMACl and TDAB sensors. Furthermore, it was revealed that the ion selectivity varies by changing the lipid concentration in each membrane. These results contribute to developing sensor membranes that respond to different anion species selectively and creating taste sensors capable of suppressing responses to tasteless anions.

Green Assay of Tolmetin Sodium Using Solid Contact Potentiometric Sensor Doped with Ionophore and Supported with Docking Study: Application to Human Plasma and Pharmaceutical Formulations

Tolmetin sodium (TOL) is a non-steroidal anti-inflammatory drug used to treat arthritis. Potentiometric ion selective electrodes (ISEs) bypass sample pre-treatment, high-tech apparatus, and toxic chemicals. The current study aimed to develop and validate a potentiometric analyser for the direct assay of TOL in pharmaceutical dosage form and human plasma. We designed an experimental approach to determine the factors that affect the performance of the developed sensor. A solid contact glassy carbon electrode was utilized as a support for the developed sensor. The interaction of TOL with several ionophore was studied using molecular docking. The optimized sensor was fabricated using dioctyl phthalate as plasticizer, tetra dodecyl ammonium bromide as anion exchanger, and β cyclodextrin as ionophore.The sensor achieved −58.78 Nernstian response within 1.00 × 10−2–2.00 × 10−6 mol l−1 linear range, 1.56 × 10−6 mol l−1 LOD, and fast response within 7 s. The greenness of the proposed method was assessed using the Analytical Eco-scale and the “Green Analytical Procedure Index” (GAPI) metric tools and compared with the reported methods and gained high scores. The proposed method has several advantages in encouraging quality control and clinical labs to routinely use the developed sensor in the assay of TOL in pharmaceutical dosage forms and human plasma.

Surface Capping Layer Prepared from the Bulky Tetradodecylammonium Bromide as an Efficient Perovskite Passivation Layer for High-Performance Perovskite Solar Cells

The power conversion efficiency (PCE) of perovskite solar cells (PSCs) has increased and levels with silicon solar cells; however, their commercialization has not yet been realized because of their poor long-term stability. One of the primary causes of the instability of PSC devices is the large concentration of defects in the polycrystalline perovskite film. Such defects limit the device performance besides triggering hysteresis and device instability. In this study, tetradodecylammonium bromide (TDDAB) was used as a postsurface modifier to suppress the density of defects from the mixed perovskite film (CsFAMA). X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) analyses validated that TDDAB binds to the mixed perovskite through hydrogen bonding. The X-ray diffraction (XRD) and two-dimensional grazing incidence wide-angle X-ray scattering (2D GIWAXS) study uncovered that the TDDAB modification formed a capping layer of (TDDA)2PbI1.66Br2.34 on the surface of the three-dimensional (3D) perovskite. The single charge transport device prepared from the TDDAB-modified perovskite film revealed that both the electron and hole defects were considerably repressed due to the modification. Consequently, the modified device displayed a champion PCE of 21.33%. The TDDAB surface treatment not only enhances the PCE but the bulky cation of the TDDAB also forms a hydrophobic capping surface (water contact angle of 93.39°) and safeguards the underlayer perovskite from moisture. As a result, the modified PSC has exhibited almost no performance loss after 30 days in air (RH ≈ 40%).

Novel microfabricated solid-contact potentiometric sensors doped with multiwall carbon-nanotubes for simultaneous determination of bisoprolol and perindopril in spiked human plasma

The main concern when developing solid contact ion selective electrodes is the choice of ion sensing membranes while keeping in mind, cost effectiveness, simplicity, potential stability, and reproducibility of results. The main aim of this work is to design microfabricated solid contact ion selective electrodes (SC-ISEs) for the selective determination of bisoprolol (BIS) and perindopril (PER) either in their combined pharmaceutical formulation or simultaneously in human plasma. The obstacle was improving the detection limit of the proposed microfabricated sensors so they can determine the plasma peak concentrations of both drugs. Two factors were considered, namely the addition of ionophores and doping the ion sensing membranes with multiwalled carbon nanotubes (MWCNTs). Four sensors were developed for BIS while two other sensors were developed for PER, and their electrochemical performance was assessed. Selectivity of the sensors was determined in presence of some degradation products, impurities and metabolites of BIS and PER. Doping the ion sensing membranes with MWCNTs proved to interfere with the formation of water layer, resulting in more stable performance. Furthermore, addition of calix[6]arene (CX6) increased the sensitivity in case of BIS sensor. The optimum results for BIS were obtained with ion sensing membrane of potassium tetrakis(4-chlorophenyl)borate, CX6 and MWCNTs. Whereas an ion sensing membrane of tetradodecylammonium bromide and MWCNTs, showed best response in case of PER. The linearity range obtained in case of BIS was 8 × 10−9–1 × 10−2 M with an LOD of 1.74 × 10−9M. While for PER, the linearity range was 1 × 10−8–1 × 10−2 M with an LOD of 9.12 × 10−9 M.

Evaluating the Effect of four Hosting Ionophores on the Performance of Anion Selective Potentiometric Sensor

AbstractA systematically designed practical approach was carried out for the optimization of an anion selective electrode for the determination of an anionic laxative, docusate sodium (DS). The PVC membrane composition and the sensor assembly were systematically optimized. Different sensors were fabricated using tetradodecylammonium bromide (TDAB), tridodecylmethylammonium bromide, tetraheptylammonium bromide as ion exchangers. The effect of ionophore was evaluated using four different host‐guest ionophores, namely; calix[8]arene, β‐cylodextrin, hydroxypropyl‐β‐cylodextrin and carboxymethyl‐β‐cylodextrin to reach the optimum membrane composition. Sensors were constructed in both liquid membrane and solid contact sensor‐assemblies. The slope, linear range, LOQ and response time for each sensor was calculated to assess their performance characteristics. Best Nernstian slope of −61.38 mV/decade and lowest quantification limit of 7.62×10−7 M was achieved by the sensor containing TDAB as ion exchanger and Calix[8]arene as ionophore in the PVC matrix using the gold wire solid contact sensor assembly. Electrode selectivity was assured in the presence of DS potential degradation product, common interfering ions and industrial excipients of tablet and gel formulations. Validation was carried out regarding the ICH validation parameters.

Artificial lipid membrane: surface modification and effect in taste sensing

In this work, an artificial lipid membrane was synthesized using tetra-dodecyl ammonium bromide (TDAB) and doped with gold nanoparticles (AuNP). The taste sensor designed using artificial lipid membrane is composed of tetradodecylammonium bromide (TDAB) as a lipid, dioctylphenyl phosphonate (DOPP) as a plasticizer, and polyvinyl chloride (PVC) as a supporting polymer in the ratio of 1:3:2. The lipid/polymer membrane acts as the recognition element which transforms the taste information generated by the chemical substances into an electric potential change. The fundamental taste analytes (like fructose for sweetness, HCl for sourness, NaCl for saltiness, MgCl2 for bitterness and MSG for umami) were used to study the effect of doping on taste sensing at different concentrations (10μM to 10mM). The study was based on the open circuit potential (OCP) change of the membrane with the analytes. The observations implicate that the doping increases the specificity of the artificially synthesized lipid membrane taste sensor for the sweet analytes, particularly for fructose.

Validated potentiometric method for the determination of sulfacetamide sodium; application to its pharmaceutical formulations and spiked rabbit aqueous humor

Specific, accurate and precise electrochemical method was developed and validated for the determination of sulfacetamide sodium in presence of its co-formulated drug (prednisolone acetate) and its pharmacopoeial impurities. The method was based on fabrication of membrane sensor. The characteristics of electrochemical response were estimated, and the proposed sensor displayed excellent characteristics for the determination of sulfacetamide sodium in bulk powder, laboratory prepared mixtures, dosage forms and in spiked biological fluid (Rabbit aqueous humor). The sensor was constructed through the use of tetradodecylammonium bromide (TDB) as an anion exchanger and 2-nitrophenyl octyl ether (NPOE) as a plasticizer in polyvinyl chloride (PVC) matrix. The performance characteristics, sensitivity and selectivity were evaluated according to IUPAC guidelines. Linearity was achieved over the concentration range of 1 × 10−4.5–1 × 10−2 M with Nernstian slope of 51.086 mV/decade over the pH range of 5–7. The sensor showed a rapid response (10–15 s) and good stability (up to 4 weeks). The obtained results were statistically compared with the official methods and no significant difference was found regarding accuracy and precision.

Characterization of three new condensation particle counters for sub-3 nm particle detection during the Helsinki CPC workshop: the ADI versatile water CPC, TSI 3777 nano enhancer and boosted TSI 3010

Abstract. In this study we characterized the performance of three new particle counters able to detect particles smaller than 3 nm during the Helsinki condensation particle counter (CPC) workshop in summer 2016: the Aerosol Dynamics Inc. (ADI; Berkeley, USA) versatile water condensation particle counter (vWCPC), TSI 3777 nano enhancer (TSI Inc., Shoreview, USA) and modified and boosted TSI 3010-type CPC from Université Blaise Pascal called a B3010. The performance of all CPCs was first measured with charged tungsten oxide test particles at temperature settings which resulted in supersaturation low enough to not detect any ions produced by a radioactive source. Due to similar measured detection efficiencies, additional comparison between the 3777 and vWCPC were conducted using electrically neutral tungsten oxide test particles and with positively charged tetradodecylammonium bromide. Furthermore, the detection efficiencies of the 3777 and vWCPC were measured with boosted temperature settings yielding supersaturation which was at the onset of homogeneous nucleation for the 3777 or confined within the range of liquid water for the ADI vWCPC. Finally, CPC-specific tests were conducted to probe the response of the 3777 to various inlet flow relative humidities, of the B3010 to various inlet flow rates and of the vWCPC to various particle concentrations. For the 3777 and vWCPC the measured 50 % detection diameters (d50s) were in the range of 1.3–2.4 nm for the tungsten oxide particles, depending on the particle charging state and CPC temperature settings, between 2.5 and 3.3 nm for the organic test aerosol, and in the range of 3.2–3.4 nm for tungsten oxide for the B3010.

High performance separation of quaternary amines using microchip non-aqueous electrophoresis coupled with contactless conductivity detection

This study describes the development of an analytical methodology for the separation of quaternary amines using non-aqueous microchip electrophoresis (NAME) coupled with capacitively coupled contactless conductivity detection (C4D). All experiments were performed using a commercial microchip electrophoresis system consisting of a C4D detector, a high-voltage sequencer and a microfluidic platform to assemble a glass microchip with integrated sensing electrodes. The detection parameters were optimized and the best response was reached applying a 700-kHz sinusoidal wave with 14Vpp excitation voltage. The running electrolyte composition was optimized aiming to achieve the best analytical performance. The mixture containing methanol and acetonitrile at the proportion of 90:10 (v:v) as well as sodium deoxycholate provided separations of ten quaternary amines with high efficiency and baseline resolution. The separation efficiencies ranged from 8.7×104 to 3.0×105 plates/m. The proposed methodology provided linear response in the concentration range between 50 and 1000μmol/L and limits of detection between 2 and 27μmol/L. The analytical feasibility of the proposed methodology was tested in the determination of quaternary amines in corrosion inhibitor samples often used for coating oil pipelines. Five quaternary amines (dodecyltrimethylammonium chloride, tetradecyltrimetylammonium bromide, cetyltrimethylammonium bromide, tetraoctylammonium bromide and tetradodecylammonium bromide) were successfully detected at concentration levels from 0.07 to 6.45mol/L. The accuracy of the developed methodology was investigated and the achieved recovery values varied from 85 to 122%. Based on the reported data, NAME-C4D devices exhibited great potential to provide high performance separations of hydrophobic compounds. The developed methodology can be useful for the analysis of species that usually present strong adsorption on the channel inner walls.

A Nitrate Ion-Selective Electrode Based on Tetradodecylammonium Bromide

A Nitrate Ion-Selective Electrode Based on Tetradodecylammonium Bromide

Analysis of a Lipid/Polymer Membrane for Bitterness Sensing with a Preconditioning Process.

It is possible to evaluate the taste of foods or medicines using a taste sensor. The taste sensor converts information on taste into an electrical signal using several lipid/polymer membranes. A lipid/polymer membrane for bitterness sensing can evaluate aftertaste after immersion in monosodium glutamate (MSG), which is called “preconditioning”. However, we have not yet analyzed the change in the surface structure of the membrane as a result of preconditioning. Thus, we analyzed the change in the surface by performing contact angle and surface zeta potential measurements, Fourier transform infrared spectroscopy (FTIR), X-ray photon spectroscopy (XPS) and gas cluster ion beam time-of-flight secondary ion mass spectrometry (GCIB-TOF-SIMS). After preconditioning, the concentrations of MSG and tetradodecylammonium bromide (TDAB), contained in the lipid membrane were found to be higher in the surface region than in the bulk region. The effect of preconditioning was revealed by the above analysis methods.

Cyclodextrin based potentiometric sensor for determination of ibuprofen in pharmaceuticals and waters

In this work, a potentiometric sensor for ibuprofen monitoring in pharmaceuticals and waters is described. The sensor development relied on comparative performance evaluation of membranes based on several commercial cyclodextrins. The optimum membrane comprised 1.2 wt.% α-cyclodextrin, 65.6 wt.% o-nitrophenyloctylether plasticizer, 42% mol (relative to the molar concentration of the ionophore) of tetradodecylammonium bromide and 32.8 wt.% PVC. A conductive polymeric resin coated with the membrane used as low impedance solid contact completed the sensor device. The sensor presented a constant sensitivity of −59.0 mV dec−1 in the concentration range of 3.87 × 10−6 to 10−2 M, for samples with pH adjusted to 9. The response time was fast <15 s and reproducible (±0.8 mV) with constant performance over more than 6 months. The practical limit of detection was of (3.34 ± 0.03) × 10−6 M ibuprofen. Sample analysis enabling accurate and reproducible results as well as the ability to be coupled to samples front-end conditioning procedures used in environmental analysis is also evidenced.

The effect of lipophilic salts on surface charge in polymeric ion-selective electrodes

The effect of quaternary ammonium salts (QAS) structure and concentration in polymeric membranes on their performance in potentiometric Ion Selective Electrodes (ISEs) without ionophore is studied. The membranes with both symmetric: tetraoctylammonium bromide (TOAB), tetradodecylammonium bromide (TDDAB), tetraoctadecylammonium bromide (TODAB), and asymmetric: tridodecylmethylammonium chloride (TDMAC) and dimethyldioctadecylammonium chloride (DODMAC) quaternary ammonium salts were tested in very broad concentration range (1–10 −4%). The observed ISEs responses could not be explained within the framework of the Phase Boundary Model, but could be easily understood semi-qualitatively with help of the simple Gouy–Chapman electrical double layer theory. The latter provides a straightforward link between the electrical potential on the membrane's surface and the corresponding surface charge density. Assuming that the electrical potential difference measured in ISEs originates from adsorption of surface active ions (tetraalkylammonium cations, QA +) and co-adsorption of anions present in the sample, the surface charge density was calculated using the Grahame equation. We postulate that the positive charge provided by adsorption of QA + at the membrane's surface provides a constant positive charge density, dependent on the QAS surface activity and concentration. This positive charge is partially neutralised by anions originating either from QAS in the membrane, or from inorganic electrolyte in the contacting aqueous phase (sample). This process could explain the dependence of electrical potential difference measured in ISEs on the concentration and type of both QAS and inorganic anions present in the sample (the latter known as “Hofmeister pattern” in potentiometry). Also the pH sensitivity of ISEs with low-QAS content membranes can be explained in the framework of the proposed model by a competition for adsorption sites on the membrane surface between QAS and high surface activity of hydroxide ions.

Surfactant-Assisted Synthesis of Metal-Phosphonate Inhibitor Nanoparticles and Transport in Porous Media

Summary A surfactant-assisted synthesis route was developed to form nanometer-size metal-phosphonate particles. The purpose is to develop a new treatment method for scale control. Aqueous solutions of calcium chloride and zinc chloride were mixed with a basic solution of either diethylenetriamine-penta (methylene phosphonate) (DTPMP) or bis-hexamethylenetriamine penta (methylene phosphonate) (BHPMP) in the presence of tetradodecylammonium bromide (TTAB) or sodium dodecyl sulfate (SDS) surfactant to form nanometer-size particles. The physical and chemical properties of the fabricated nanoparticles have been evaluated carefully. A large number of fabrication procedures are screened, and only those that yield metal-phosphonate particles of 50–200 nm in diameter are evaluated further. Furthermore, these nanoparticles should meet the criteria of forming stable suspension for more than 1 week at 70°C in 2% KCl solution. The nanoparticles can travel through the porous media and be deposited into the formation during a shut-in period. When production resumes, the inhibitor nanoparticles are dissolved into the produced fluid to prevent scale formation. The potential application of synthesized nanoparticles in scale treatment in oil fields has been tested by laboratory squeeze simulations, in which the nanoparticles were placed a distance away from the injection port, retained by the porous media, and returned slowly during flow-back with synthetic brine. The retention and long-term-flowback performance of metal-phosphonate particles is reported.

Microfluidic Polymer Chip with an Embedded Ion-Selective Electrode Detector for Nitrate-Ion Assay in Environmental Samples

A nitrate ion-selective electrode (NO(3)(-)-ISE) has been developed based on tetradodecylammonium bromide as an anion exchanger and 2-nitrophenyl octyl ether as a plasticizer. The NO(3)(-)-ISE shows an almost Nernstian response to nitrate ion over a concentration range between 1.0 x 10(-6) and 1.0 x 10(-1) M, with an anionic slope of -57.7 +/- 0.7 mV/decade. The selectivity coefficients of the NO(3)(-)-ISE for nitrate ion against chloride and sulfate (log k(NO(3)(-)Cl(-))(pot) = -2.42 and log k(NO(3)(-)SO(4)(2-))(pot) = -4.33) were obtained. A microfluidic polymer chip was fabricated using polystyrene plates and stainless-steel wires as a template for the channel. The microfluidic polymer chip is composed of a mixing chip and a NO(3)(-)-ISE detector chip. The microfluidic polymer chip, integrated with a NO(3)(-)-ISE detector consisting of the NO(3)(-)-ISE and a Na(+)-ISE as a reference electrode, showed an almost Nernstian response to nitrate ion over a concentration range between 1.0 x 10(-5) and 1.0 x 10(-1) M, with an anionic slope of -54.3 +/- 1.3 mV/decade. The microfluidic polymer chip was then applied to the determination of nitrate ion in environmental water samples, such as a tap water, a well-water sample and water for agricultural use.

Synthesis of the Gold Nanocubes by Electrochemical Method with Surfactant Solution and Acetone Solvent Addition

Monodispersed gold nanocubes of highly uniform size were fabricated by a simple electrochemical method. The lengths of the edges of the gold nanocubes were about 30 nm. The growth solution was prepared from two cationic surfactant solutions as micelle templates with added acetone solvent. The primary surfactant was hexadecyltrimethylammonium bromide (CTAB) and the co-surfactant was tetradodecylammonium bromide (TTAB).

Preparation of Dendrimer-Like Gold Nanoparticles by Electrochemical Method

In this article, we demonstrate the synthesis of dendrimer-like gold nanoparticles (DGNs) by an electrochemical method using micelle templates formed by two surfactants with various amounts of toluene solvent, the primary surfactant being hexadecyltrimethylammonium bromide (CTAB) and the cosurfactant being tetradodecylammonium bromide (TTAB). To investigate the influence of toluene solvent on the DGNs, the amount of toluene was varied in the range from 10 to 50 μL. It was found that the shape of particles was changed from sphere to dendrimer-like shape, and the UV-vis optical absorption measurement revealed a pronounced red shift of the surface plasmon resonance (SPR) peak from 526 to 548 nm.

Low molecular mass organogelator based gel electrolyte gelated by a quaternary ammonium halide salt for quasi-solid-state dye-sensitized solar cells

Quasi-solid-state dye-sensitized solar cells (DSC) are fabricated using tetradodecylammonium bromide as a low molecular mass organogelator (LMOG) to form gel electrolyte with a high solution-to-gel transition temperature ( T SG) of 75 °C to hinder flow and volatilization of the liquid. The steady-state voltammograms reveal that the diffusion of the I 3 − and I − in the gel electrolyte is hindered by the self-assembled network of the gel. An increased interfacial exchange current density ( j 0) of 4.95 × 10 −8 A cm −2 and a decreased electron recombination lifetime ( τ) of 117 ms reveal an increased electron recombination at the dyed TiO 2 photoelectrode/electrolyte interface in the DSC after gelation. The results of the accelerated aging tests show that the gel electrolyte based dye-sensitized solar cell can retain over 93% of its initial photoelectric conversion efficiency value after successive heating at 60 °C for 1000 h, and device degradation is negligible after one sun light soaking with UV cutoff filter for 1000 h.

Fabrication of Gold Nanocubes by the Electrochemical Method

This paper demonstrates synthesis of gold nanocubes with uniform size about 30 nm by a simple electrochemical method. The surfactant cetyltrimethylammonium bromide (CTAB) and tetradodecylammonium bromide (TTAB) were used as the stabilizer and micelle template to control the size and shape of gold nanocubes. In this study, acetone solvent was injected to the electrolyte solution with surfactant, changing the surfactant micelle-template, leading to the formation of gold nanocubes. The gold nanocubes have a surface plasmon resonance (SPR) band at a wavelength of about 530 nm. The gold nanodumbbells have been determined to be single-crystalline with a face-centered cubic (fcc) structure by X-ray diffraction (XRD) analysis.

Electrochemically Controlling the Size of Gold Nanoparticles

This work demonstrates the electrochemical synthesis of nanoscale gold particles using a surfactant solution. Tetradodecylammonium bromide (TTAB) surfactant was applied to stabilize the gold clusters. Experimental results reveal that the size of the produced gold nanoparticles is controlled by the amount of TTAB surfactant, the current density, and the growth temperature. The size of the gold nanoparticles can be controlled in the range . The particle size decreases as the amount of TTAB increases from . The optimal current density in this study was . The size of the produced nanoparticles increases linearly with the growth temperature from . The gold nanoparticles were observed by transmission electron microscopy, ultraviolet-visible spectrometry, and X-ray photoelectron spectroscopy. A mechanism for electrochemically controlling the size of the gold nanoparticles is presented.