Synthesis of novel poly(amidoxime) grafted multiwall carbon nanotube gel and uranium adsorption.

This is the first report on the synthesis of a new functional nanocomposite gel containing amidoxime functionalized multiwall carbon nanotube (AO-MWNT-FNC GEL). The surface morphology of AO-MWNT-FNC GEL was investigated by field emission scanning electron microscopy. The modification of gel with amidoxine groups was confirmed by Fourier transform infra red spectroscopy. The AO-MWNT-FNC GEL provides effective binding with uranium ions as was ascertained by X-ray photoelectron spectroscopy. The AO-MWNT-FNC GEL was utilized as the new adsorbent for the recovery of uranium ions from aqueous solution. UV-visible spectroscopy was used to monitor the adsorption capacity of the AO-MWNT-FNC GEL toward uranium ions. The influence of initial uranium ion concentration and solution pH on the adsorption capacity of the AO-MWNT-FNC GEL were studied in batch experiments. The new FNC-GEL designed in this study is distinguished by higher adsorption capacity for uranium ions due to the synergistic contributions from high surface area of MWNT and the functional AO groups in FNC-GEL and exhibits potential for efficient recovery of uranium ions.

Non-covalent bonding interaction of surfactants with functionalized carbon nanotubes in proton exchange membranes for fuel cell applications.

Dispersion of functionalized multiwalled carbon nanotubes (MWCNTs) in proton exchange membranes (PEMs) was conducted via non-covalent bonding between benzene rings of various surfactants and functionalized MWCNTs. In the solution casting method, dispersion of functionalized MWCNTs in PEMs such as Nafion membranes is a critical issue. In this study, 1 wt.% pristine MWCNTs (p-MWCNTs) and oxidized MWCNTs (ox-MWCNTs) were reinforced in Nafion membranes by adding 0.1-0.5 wt.% of a surfactant such as benzalkonium chloride (BKC) as a cationic surfactant with a benzene ring, Tween-80 as a nonanionic surfactant without a benzene ring, sodium dodecylsulfonate (SDS) as an anionic surfactant without a benzene ring, or sodium dodecylben-zenesulfonate (SDBS) as an anionic surfactant with a benzene ring and their effects on the dispersion of nanocomposites were then observed. Among these surfactants, those with benzene rings such as BKC and SDBS produced enhanced dispersion via non-covalent bonding interaction between CNTs and surfactants. Specifically, the surfactants were adsorbed onto the surface of functionalized MWCNTs, where they prevented re-aggregation of MWCNTs in the nanocomposites. Furthermore, the prepared CNTs reinforced nanocomposite membranes showed reduced methanol uptake values while the ion exchange capacity values were maintained. The enhanced properties, including thermal property of the CNTs reinforced PEMs with surfactants, could be applicable to fuel cell applications.

Sensitive electrochemical detection of superoxide anion using gold nanoparticles distributed poly(methyl methacrylate)-polyaniline core-shell electrospun composite electrode.

In the present communication, a novel composite nanofibrous electrode is developed for the detection of superoxide anion (O(2)˙(-)) in phosphate buffered saline (PBS). The composite fiber electrode is fabricated by dispersing gold nanoparticles onto poly(methyl methacrylate) (PMMA)-polyaniline (PANI) core-shell electrospun nanofibers. The constructed architecture is proven to be a favorable environment for the immobilization of the enzyme, superoxide dismutase (SOD). Direct electron transfer is achieved between SOD and the electrode with an electron transfer rate constant of 8.93 s(-1). At an applied potential of +300 mV, PMMA/PANI-Au(nano)/SOD-ESCFM shows highly sensitive detection of O(2)˙(-). In addition to this, quantification of different activities of SOD is realized at PMMA/PANI-Au(nano)/SOD-ESCFM. These analytical features offer great potential for construction of the third-generation O(2)˙(-) biosensor.

Synthesis and characterization of polyaniline grafted multiwalled carbon nanotube loaded Nafion-silica nanocomposite membrane.

The preparation and characterization results of a new nanocomposite, polyaniline (PANI) grafted multiwalled carbon nanotube (MWNT) loaded Nafion-silica, (designated as Nafion-silica/MWNT-g-PANI), are reported in this paper. The preparation involves the formation of a silica network in a Nafion membrane and the subsequent loading of polyaniline-grafted multiwalled carbon nanotubes (MWNT-g-PANI) onto the Nafion-silica nanocomposite. The new nanocomposite, Nafion-silica/ MWNT-g-PANI, was characterized as to its morphology, structure and properties. The conductivity and methanol permeability of the nanocomposite membranes were evaluated.

A novel glucose biosensor based on immobilization of glucose oxidase into multiwall carbon nanotubes-polyelectrolyte-loaded electrospun nanofibrous membrane.

Nanofibrous glucose electrodes were fabricated by the immobilization of glucose oxidase (GOx) into an electrospun composite membrane consisting of polymethylmethacrylate (PMMA) dispersed with multiwall carbon nanotubes (MWCNTs) wrapped by a cationic polymer (poly(diallyldimethylammonium chloride) (PDDA)) and this nanofibrous electrode (NFE) is abbreviated as PMMA-MWCNT(PDDA)/GOx-NFE. The NFE was characterized for morphology and electroactivity by using electron microscopy and cyclic voltammetry, respectively. Field emission transmission electron microscopy (FETEM) image reveals the dispersion of MWCNT(PDDA) within the matrix of PMMA. Cyclic voltammetry informs that NFE is suitable for performing surface-confined electrochemical reactions. PMMA-MWCNT(PDDA)/GOx-NFE exhibits excellent electrocatalytic activity towards hydrogen peroxide (H(2)O(2)) with a pronounced oxidation current at +100 mV. Glucose is amperometrically detected at +100 mV (vs. Ag/AgCl) in 0.1M phosphate buffer solution (PBS, pH 7). The linear response for glucose detection is in the range of 20 microM to 15 mM with a detection limit of 1 microM and a shorter response time of approximately 4 s. The superior performance of PMMA-MWCNT(PDDA)/GOx-NFE is due to the wrapping of PDDA over MWCNTs that binds GOx through electrostatic interactions. As a result, an effective electron mediation is achieved. A layer of nafion is made over PMMA-MWCNT(PDDA)/GOx-NFE that significantly suppressed the electrochemical interference from ascorbic acid or uric acid. In all, PMMA-MWCNT(PDDA)/GOx-nafion-NFE has exhibited excellent properties for the sensitive determination of glucose like high selectivity, good reproducibility, remarkable stability and without interference from other co-existing electroactive species.

Novel method to prepare polystyrene-based monolithic columns for chromatographic and electrophoretic separations by microwave irradiation.

Microwave irradiation can provide a viable alternative to the traditional means such as ultraviolet light and thermal initiation for the preparation of monolithic capillary columns. Polystyrene-based monolithic stationary phases were prepared in situ in fused-silica capillaries and simultaneously in vials. The column permeability, electrophoretic and chromatographic behavior were evaluated using pressure-assisted capillary electrochromatography (pCEC), capillary electrochromatography (CEC) and low pressure liquid chromatography (LPLC). With an optimal monolithic material, the largest theoretical plates for preparing the column could be close to 18,000 plates/m for thiourea in the mode of pCEC. Furthermore, the influence of the composition of the porogenic solvents (toluene/isooctane) on the morphology of organic-based monoliths [poly(styrene-divinylbenzene-methacrylic acid)] was systematically studied with mercury intrusion porosimetry and scanning electron microscopy. The monoliths which were prepared with a high content of isooctane had a bigger pore size and better permeability, and hence resulted in a faster separation.

Fabrication of functional poly(thiophene) electrode for biosensors.

Three-type polymer electrodes such as poly(Th), poly(Th-AP) and poly(Th-AP-TAA) were fabricated, respectively, by electro-oxidative polymerization of thiophene (Th), mixture of Th and 2-aminophenol (AP), and mixture of Th, AP and 3-thiopheneacetic acid (TAA) on the surface of indium tin oxide (ITO) glass by cyclic voltammetry (CV). The polymer electrodes were electrodeposited by cycling the potential between -1.0 and +2.5 V in acetonitrile containing 50 mM tetrabutylammoniumhexafluorophosphate (TBAF(6)P). The surface morphology of polymer electrodes was investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM) analysis. The surface morphology of the poly(Th) showed typical roughness and fractal-like growth patterns, and the morphologies of poly(Th-AP) and poly(Th-AP-TAA) were dramatically changed. The water contact angle at the poly(Th-AP-TAA) (23 degrees) is lower in comparison to poly(Th) (47 degrees ). The functional groups (-OH) and carboxylic acid (-COOH) group play an important role. Horseradish peroxidase was loaded onto poly(Th-AP-TAA) surface and used to test the sensing of H(2)O(2).

Self-assembly and graft polymerization route to Monodispersed Fe3O4@SiO2--polyaniline core-shell composite nanoparticles: physical properties.

This study describes the synthesis of monodispersed core-shell composites of silica-modified magnetic nanoparticles and conducting polyaniline by self-assembly and graft polymerization. Magnetic ferrite nanoparticles (Fe3O4) were prepared by coprecipitation of Fe+2 and Fe+3 ions in alkaline solution, and then silananized. The silanation of magnetic particles (Fe3O4@SiO2) was carried out using 3-bromopropyltrichlorosilane (BPTS) as the coupling agent. FT-IR spectra indicated the presence of Fe--O--Si chemical bonds in Fe3O4@SiO2. Core-shell type nanocomposites (Fe3O4@SiO2/PANI) were prepared by grafting polyaniline (PANI) on the surface of silanized magnetic particles through surface initiated in-situ chemical oxidative graft polymerization. The nanocomposites were characterized by high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), Fourier transform infrared (FTIR) spectra, UV-visible spectroscopy, photoluminescence (PL) spectra, electrical conductivity and magnetic characteristics. HRTEM images of the nanocomposites revealed that the silica-modified magnetic particles made up the core while PANI made up the shell. The XPS spectrum revealed the presence of silica in the composites, and the XRD results showed that the composites were more crystalline than pure PANI. PL spectra show that composites exhibit photoluminescent property. Conductivity of the composites (6.2 to 9.4 x 10(-2) S/cm) was higher than that of pristine PANI (3.7 x 10(-3) S/cm). The nanocomposites exhibited superparamagnetism. Formation mechanism of the core-shell structured nanocomposites and the effect of modified magnetic nanoparticles on the electro-magnetic properties of the Fe3O4@SiO2/PANI nanocomposites are also investigated. This method provides a new strategy for the generation of multi-functional nanocomposites that composed of other conducting polymers and metal nanoparticles.

Self-assembly directed synthesis of poly(ortho-toluidine)-metal(gold and palladium) composite nanospheres.

Poly(ortho-toluidine) (POT)-gold (Au) and palladium (Pd) composite nanospheres were successfully synthesized by the reaction of o-toluidine with the corresponding metal (Au or Pd) colloidal solution through self-assembly process in the presence of dodecylbenzenesulfonic acid (DBSA), which acts as both a dopant and surfactant, and ammonium peroxydisulfate as an oxidizing agent. The composites (POT-DBSA/Au or Pd) were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, UV-Visible (UV-Vis) spectroscopy, and electrical conductivity measurements. TEM images of the nanocomposites reveal that metal (Au or Pd) nanoparticles were well dispersed on POT spheres. TGA and XRD results show that the composites exhibit high thermal stability and are more crystalline compared with pristine POT. It was found that the electrical conductivity of the POT-DBSA/Au or Pd composites is 2 orders of magnitude higher than that of pristine polymer. Also, the POT-DBSA/Pd composite exhibits magnetic property. The formation mechanism of the POT-DBSA/Au or Pd composite nanosphere is discussed.

Synthesis and characterization of processable multi-walled carbon nanotubes-sulfonated polydiphenylamine graft copolymers.

Water soluble and processable nanocomposites composed of multi-walled carbon nanotubes (MWNTs) and poly(diphenylamine sulfonic acid) (PDPASA) are synthesized and characterized. Two types of methodologies are adopted. MWNTs are covalently functionalized with 2,5-diaminobenzene sulfonic acid (DABSA) and further in situ polymerized with diphenylamine-4-sulfonic acid (DPASA). This results in the formation of nanocomposites, MWNT(DABSA)-g-PDPASA, in which PDPASA is presented as the graft chains onto MWNTs. In another approach, DPASA is in situ polymerized in presence of unfunctionalized MWNTs, results in a nanocomposite in which MWNTs are present as entrapped mass in PDPASA matrix. Both nanocomposites are found to be water soluble and can form free standing films. The conductivity of MWNT(DABSA)-g-PDPASA and MWNT/PDPASA is found to be 1.25 mS x cm(-1) and 0.65 mS x cm(-1), respectively, which is higher than that of pristine PDPASA (0.25 x 10(-5) S x cm(-1)). The nanocomposites are characterized for their structure, morphology, optical and thermal properties.

Fabrication of a gold nanoparticles decorated carbon nanotubes based novel modified electrode for the electrochemical detection of glucose.

A modified electrode based on gold nanoparticles decorated multiwall carbon nanotubes (MWNTs), MWNT-Au(nano)-ME is fabricated. MWNTs are functionalized with 4-aminothiophenol and coated over the glassy carbon electrode. Further, Au nanoparticles are deposited into MWNTs coated GC electrode by electrochemical reduction of HAuCl4. Field emission transmission electron microscope (FETEM) image shows the formation of approximately 5 nm sized Au nanoparticles without any agglomeration on the MWNTs surface. Further, the presence of Au nanoparticles is confirmed through X-ray photoelectron spectroscopic (XPS) studies. The electrocatalytic activity of the MWNT-Au(nano)-ME towards the detection of glucose is investigated. MWNT-Au(nano)-ME shows enhanced current response than pristine MWNT-ME over the entire (+0.05 to +0.80 V) potential range. The modified electrode shows linear response to current with the concentration of glucose between 1 and 20 mM. Larger current responses to glucose oxidation are witnessed at +0.60 V than at +0.05 V. However, a large interference signal, reflecting the accelerated oxidation of electroactive interference is observed at +0.60 V. No overlapping signal from the interferents such as ascorbic acid, acetaminophen, and dopamine are observed at the MWNT-Au(nano)-ME at +0.05 V. Further, the MWNT-Au(nano)-ME shows high resistance to the toxictiy of chloride ions.

Enhanced electrochemical detection of ketorolac tromethamine at polypyrrole modified glassy carbon electrode.

A glassy carbon electrode modified with a coating of polypyrrole (Ppy) exhibited an attractive performance for the detection and determination of a non-steroidal and non-narcotic analgesic compound, ketorolac tromethamine (KT). Cyclic voltammetry, differential pulse and square wave voltammetry were used in a combined way to identify the electrochemical characteristics and to optimize the conditions for detection. For calibrating and estimating KT, square-wave voltammetry was mainly used. The drug shows a well-defined peak at -1.40 V vs. Ag/AgCl in the acetate buffer (pH 5.5). The existence of Ppy on the surface of the electrode gives higher electrochemical active sites at the electrode for the detection of KT and preconcentrate KT by adsorption. The square-wave stripping voltammetric response depends on the excitation signal and the accumulation time. The calibration curve is linear in the range 1 x 10(-11) to 1 x 10(-7) M with a detection limit of 1.0 x 10(-12) M. Applicability to serum samples was also demonstrated. A detection limit of 1.0 ng ml for serum was observed. Square-wave voltammetry shows superior performance over UV spectroscopy and other techniques.

Incorporation of silver nanoparticles on the surface of orthodontic microimplants to achieve antimicrobial properties.

OBJECTIVE: Microbial aggregation around dental implants can lead to loss/loosening of the implants. This study was aimed at surface treating titanium microimplants with silver nanoparticles (AgNPs) to achieve antibacterial properties. METHODS: AgNP-modified titanium microimplants (Ti-nAg) were prepared using two methods. The first method involved coating the microimplants with regular AgNPs (Ti-AgNP) and the second involved coating them with a AgNP-coated biopolymer (Ti-BP-AgNP). The topologies, microstructures, and chemical compositions of the surfaces of the Ti-nAg were characterized by scanning electron microscopy (SEM) equipped with energy-dispersive spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS). Disk diffusion tests using Streptococcus mutans, Streptococcus sanguinis, and Aggregatibacter actinomycetemcomitans were performed to test the antibacterial activity of the Ti-nAg microimplants. RESULTS: SEM revealed that only a meager amount of AgNPs was sparsely deposited on the Ti-AgNP surface with the first method, while a layer of AgNP-coated biopolymer extended along the Ti-BP-AgNP surface in the second method. The diameters of the coated nanoparticles were in the range of 10 to 30 nm. EDS revealed 1.05 atomic % of Ag on the surface of the Ti-AgNP and an astounding 21.2 atomic % on the surface of the Ti-BP-AgNP. XPS confirmed the metallic state of silver on the Ti-BP-AgNP surface. After 24 hours of incubation, clear zones of inhibition were seen around the Ti-BP-AgNP microimplants in all three test bacterial culture plates, whereas no antibacterial effect was observed with the Ti-AgNP microimplants. CONCLUSIONS: Titanium microimplants modified with Ti-BP-AgNP exhibit excellent antibacterial properties, making them a promising implantable biomaterial.

Fabrication and electrocatalysis of self-assembly directed gold nanoparticles anchored carbon nanotubes modified electrode.

A self-assembly directed approach was adopted to modify glassy carbon electrode (GC) with gold nanoparticles incorporation and the electrocatalytic performance of self-assembly modified electrode, GC/SA-Au-ME was critically evaluated for the oxidation of ascorbic acid (AA). The modification involves the dispersion of multi-wall carbon nanotube (MWNT) and an inclusion complex, beta-cyclodextrin-4-aminothiophenol on the surface of GC electrode in the presence of cetyltrimethylammonium bromide (CTAB). Gold nanoparticles were deposited into the self-assembled sites to fabricate the modified electrode, GC/SA-Au-ME. Another electrode (GC-Au-ME) was fabricated under similar conditions in the absence of CTAB. The electrocatalytic activity of the modified electrodes (GC/SA-Au-ME and GC-Au-ME) towards the oxidation of AA was critically compared. Cyclic voltammetry, chronoamperometry, and double potential chronoamperometry were used to evaluate the characteristics of the modified electrodes. The self-assembled electrode (GC/SA-Au-ME) shows excellent electrocatalytic activity over the other electrode, GC-Au-ME. Augmented current response, faster electron transfer kinetics (with a rate constant for electron transfer process as 3.25 x 10(4) cm3 mol(-1) s(-1)), linear range of response for the analyte (1-50 mM with an extended detection limit to 1 microM), better sensitivity, and selectivity were witnessed for the self-assembly directed modified electrode.

Preparation and characterization of polyalkene membranes modified with four different ion-exchange groups by radiation-induced graft polymerization.

Three different cation-exchange membranes with carboxylic acid, phosphoric acid, and sulfonic acid groups, and one anion-exchange membrane with a triethylamine group were prepared by radiation-induced graft polymerization. The maximum capacities of the carboxylic acid, phosphoric acid, sulfonic acid, and triethylamine groups were 3.0, 2.30, 2.43, and 1.42 mmol/g, respectively. The physico-chemical properties of the polyalkene non-woven fabric membrane with four different ion-exchange groups were examined by thermogravimetric analysis, X-ray photoelectron spectrometry (XPS), and scanning electron microscopy. The prepared ion-exchange membrane was applied to the removal of terephthalic acid in dyeing wastewater.

Comparison of monomeric and polymeric chiral stationary phases.

Two-type polymeric chiral stationary phases (pCSPs) were prepared by surface grafting of chiral acryl-type monomers on a silica gel surface modified with 3-(trimethoxysilyl)propylmethacrylate. The prepared pCSPs were characterized by IR, Fr-Raman, scanning electron microscopy, and elemental analysis. In addition, two-type monomeric chiral stationary phases (mCSPs) were also prepared. The racemic analytes were separated using the prepared mCSPs and pCSPs. The separation factor (alpha) and capacity factor (k1) of the racemic analytes for the pCSP and mCSP were compared. The alpha and k1 values of the mCSP were higher than those of the pCSP.

Retention behavior of C1-C6 aliphatic monoamines on anion-exchange and polymethacrylate resins with heptylamine as eluent.

Retention behavior of C1-C6, aliphatic monoamines (methylamine, ethylamine, propylamine, butylamine, amylamine and hexylamine) on columns (150 mm x 6 mm i.d.) packed with various anion-exchange resins (styrene-divinylbenzene (PS-DVB) copolymer-based strongly basic anion-exchange resin: TSKgel SAX, polymethacrylate-based strongly basic anion-exchange resin: TSKgel SuperQ-5PW and polymethacrylate-based weakly basic anion-exchange resin: TSKgel DEAE-5PW) and unfunctionized polymethacrylate resins (TSKgel G5000PW and TSKgel G3000PWXL) was investigated with basic solutions (sodium hydroxide and heptylamine) as the eluents. Due to strongly electrostatic repulsion (ion-exclusion effect) between these anion-exchange resins and these amines, peak resolution between these amines on these anion-exchange resin columns was unsatisfactory with both sodium hydroxide and heptylamine as the eluents. In contrast, these polymethacrylate resins were successfully applied as the stationary phases for the separation of these C1-C6 amines with heptylamine as eluent, because of both small hydrophobicity and small cation-exchange ability of these resins. Excellent simultaneous separation, highly sensitive conductimetric detection and symmetrical peaks for these C1-C6 amines were achieved on the TSKgel G3000PWXL column in 35 min with 5 mM heptylamine at pH 11.1 as the eluent.

Separation of aliphatic carboxylic acids and benzenecarboxylic acids by ion-exclusion chromatography with various cation-exchange resin columns and sulfuric acid as eluent.

The application of various hydrophilic cation-exchange resins for high-performance liquid chromatography (sulfonated silica gel: TSKgel SP-2SW, carboxylated silica gel: TSKgel CM-2SW, sulfonated polymethacrylate resin: TSKgel SP-5PW, carboxylated polymethacrylate resins: TSKgel CM-5PW and TSKgel OA-Pak A) as stationary phases in ion-exclusion chromatography for C1-C7 aliphatic carboxylic acids (formic, acetic, propionic, butyric, isovaleric, valeric, isocaproic, caproic, 2-methylhexanoic and heptanoic acids) and benzenecarboxylic acids (pyromellitic, trimellitic, hemimellitic, o-phthalic, m-phthalic, p-phthalic, benzoic, salicylic acids and phenol) was carried out using diluted sulfuric acid as the eluent. Silica-based cation-exchange resins (TSKgel SP-2SW and TSKgel CM-2SW) were very suitable for the ion-exclusion chromatographic separation of these benzenecarboxylic acids. Excellent simultaneous separation of these benzenecarboxylic acids was achieved on a TSKgel SP-2SW column (150 x 6 mm I.D.) in 17 min using a 2.5 mM sulfuric acid at pH 2.4 as the eluent. Polymethacrylate-based cation-exchange resins (TSKgel SP-5PW, TSKgel CM-5PW and TSKgel OA-Pak A) acted as advanced stationary phases for the ion-exclusion chromatographic separation of these C1-C7 aliphatic carboxylic acids. Excellent simultaneous separation of these C1-C7 acids was achieved on a TSKgel CM-5PW column (150 x 6 mm I.D.) in 32 min using a 0.05 mM sulfuric acid at pH 4.0 as the eluent.

A kinetic study on the formation of poly(4 aminodiphenylamine)/copper nanocomposite using UV-visible spectroscopy.

The course of the reaction between copper sulfate (CuSO4) and 4-aminodiphenylamine (4ADPA) was monitored by UV-visible spectroscopy in p-toluene sulfonic acid (p-TSA). Formation of poly(4-aminodiphenylamine)/copper nanoparticle composite (P4ADPA/CuNC) was witnessed through the steady increase in absorbance at 410, 580 and >700 nm. The absorbance at 410 nm as well as >700 nm are correlated to the amount of P4ADPA/CuNC formation and was subsequently used to determine the rate of formation of P4ADPA/CuNC (RP4ADPA/CuNC) at any time during the course of the reaction. RP4ADPA/CuNC shows a first-order dependence on [4ADPA] and a half-order dependence on [CuSO4]. A kinetic rate expression was established between RP4ADPA/CuNC and experimental parameters such as [4ADPA] and [CuSO4]. The rate constant for the formation of P4ADPA/CuNC was 8.98 × 10(-3) mol(-0.5) l(0.5) s(-1). Field emission scanning electron and transmission electron micrographs revealed that the morphology of the P4ADPA/CuNC was influenced by the reaction conditions.

Development of a novel cyano group containing electrochemically deposited polymer film for ultrasensitive simultaneous detection of trace level cadmium and lead.

Poly(diphenylamine-co-2-aminobenzonitrile) (P(DPA-co-2ABN)), a cyano group containing conducting polyaniline derivative, has been electrodeposited developed as the new material and utilized for the simultaneous electrochemical determination of trace levels of cadmium (Cd(2+)) and lead (Pb(2+)). P(DPA-co-2ABN) film preconcentrates effectively through cyano chelation and electrochemically strips the heavy metal ions with well separated potentials, which are beneficially utilized for ppb level simultaneous detection of Cd(2+) and Pb(2+). Differential pulse voltammetry studies revealed that Cd(2+) and Pb(2+) ions were simultaneously stripped with well-defined, separated and sharp peaks for Cd(2+) and Pb(2+). The influence of various operational parameters such as pulse amplitude, pulse time, scan rate, initial potential, end potential, accumulation potential and accumulation time on the electrochemical stripping of heavy metals were investigated in details. Under the optimal conditions, good linear correlations were obtained from 1.26 to 907.8 ppm for Cd(2+) and 0.26 to 58.73 ppm for Pb(2+), respectively. Low detection limits for Cd(2+) and Pb(2+), 0.255 ppm and 0.165 ppm, respectively, were observed. The practical utility of the new procedure was demonstrated in real samples.