Synthesis of activated biochar from sustainable bamboo resources: An environment-friendly and low-cost solution for palladium (II) removal from wastewater.

This article highlights the developing capabilities of low-cost activated biochar from bamboo waste used for Palladium (II) (Pd(II)) separation from man-made electroless plating solutions (ELP). From a novelty perspective, this article addresses the effect of coupled sonication and surfactant for the adsorptive elimination of Pd(II) on Bamboo stem activated carbon (BSAC) from ELP. The optimal activation procedure referred to an acid-to-bamboo ratio of 4:1 at sintering of 600-900 °C, which provided an activated carbon (AC) adsorbent with surface area analysis (BET) of 1014.36 m2/g, a value comparable to the commercially procured AC. Pd(II) adsorption characteristics in the solution of Pd with 50-500 mg/L concentration range were evaluated utilizing both agitation and sonication. Adsorption time, pH, dose, and adsorbate concentration were among the pertinent optimal batch adsorption parameters that were found. When utilizing ELP solutions without surfactant, the proposed adsorbent for agitation-assisted adsorption had a simultaneous improvement in metal intake of 6.68-43.2 mg/g and removal efficiency of 72.96-54.5% (cTAB). For cTAB-containing solutions, sonication and agitation-assisted adsorption were outperformed in terms of removal efficiency of 80.32-60.16% and metal uptake of 6.69-50.13 mg/g. Equilibrium, kinetic, and thermodynamic models with good fitting to the reported Pd(II) adsorption properties have been developed.

Assessment of cetyl-trimethyl-ammonium bromide (CTAB) based method for the extraction of soil-transmitted helminth DNAs from stools for molecular dagnostic of soil-transmitted helminthiasis.

Although several protocols were developed to extract DNA for soil-transmitted helminthiasis diagnostic, amplifying these extracts remains challenging due to DNA polymerase inhibitors. This study aimed to assess a DNA extraction method for efficient detection of soil-transmitted helminth species by determining stool mass and the type of DNA polymerase that can be used for this extraction method. For this study, 141 stool samples harbouring soil-transmitted eggs and 50 samples without egg were obtained from school-aged children of Makenene in the Centre region of Cameroon. DNA was extracted from 10, 20, 40 and 80 mg of stool using commercial kit and/or cetyltrimethylammonium bromide (CTAB)-based method. The amount of stool for molecular diagnostic of soil-transmitted helminthiasis was determined by amplifying Ascaris lumbricoides DNA. The performances of three DNA polymerases and CTAB-based method were assessed by amplifying DNA of different soil-transmitted helminth species. For this study, 94 stools with A. lumbricoides eggs, 39 with Trichuris trichuria and 15 with hookworm were analyzed. DNA of A. lumbricoides, T. trichuria, Necator americanus and Ancylostoma duodenale were detected in 97.9% of extracts from stools harbouring soil-transmitted helminth eggs. Soil-transmitted helminth DNAs were significantly (X2 = 17.66; df = 3; p ã€ˆ00001) more amplified in extracts from 10 and 20 mg than those from 40 and 80 mg. The amplification rate with "Q5 high fidelity DNA polymerase" was significantly (X2 = 30.54; df = 2; p < 0.00001) higher than that of other DNA polymerases. Multiplex-PCR confirmed co-infections of A. lumbricoides with either T. trichuria or N. americanus. The extraction cost for the CTAB-based method was $1.45. This method appearedis reliable and 3 times cost effective than commercial kit. Its combination with the "Q5 high fidelity DNA polymerase" may improve soil-transmitted helminthiasis diagnostic.

Synergistic adsorption and degradation of diclofenac by zero-valent iron modified spent bleaching earth carbon: Mechanism and toxicity assessment.

Diclofenac (DCF) is a drug compound that exists widely in water bodies, which may pose a threat to the ecological environment. In this study, spent bleaching earth (SBE) was pyrolyzed, modified with cetyltrimethylammonium bromide (CTAB) and loaded with zero-valent iron (nZVI) to obtain CTAB-SBE@C-nZVI. The effects of CTAB concentration, Fe0 loading, CTAB-SBE@C-nZVI dosage, and initial pH value on the removal efficiency of DCF were studied. The results showed that the DCF removal efficiency could reach a maximum of 87.0% with 2.0 g/L dosage of the optimal material, which was prepared under the conditions of 30 mmol/L CTAB concentration, 25% Fe0 loading, and initial pH 5. It indicated that the strong adsorption of the material and the reduction effect of nZVI can achieve high-efficiency removal of DCF. Based on the detected reaction intermediate products, four possible degradation paths were inferred. The toxicity assessment of DCF and its intermediates manifested that the degradation of DCF by CTAB-SBE@C-nZVI was a process of gradual dechlorination and toxicity reduction. CTAB-SBE@C-nZVI displayed excellent DCF removal efficiency, good stability and environmental friendliness, achieving wastes treat wastes and exhibiting good prospects.

Comparative assessment of three RNA extraction methods for obtaining high-quality RNA from Candida viswanathii biomass.

Isolating high quality RNA is a limiting factor in molecular analysis, since it is the base for transcriptional studies. The RNA extraction method can directly affect the RNA quality and quantity, as well as, its overall cost. The industrial importance of the yeast genus Candida in several sectors comes from their capacity to produce Lipases. These enzymes are one of the main metabolites produced by some Candida species, and it has been shown that Candida yeast can biodegrade petroleum hydrocarbons and diesel oil from biosurfactants that they can produce, a feature that turns these organisms into potential combatants for bioremediation techniques. Thus, this study aimed to determine an efficient method for isolating high quality RNA from Candida viswanathii biomass. To achieve this aim, three different RNA extraction methods, TRIzol, Hot Acid Phenol, and CTAB (Cetyltrimethylammonium Bromide), were tested. The three tested methods allowed the isolation of high-quality RNA from C. viswanathii biomass and yielded suitable RNA quantity for carrying out RT-qPCR studies. In addition, all methods displayed high sensitivity for the expression analysis of the CvGPH1 gene through RT-qPCR, with TRIzol and CTAB showing the best results and the CTAB method displaying the best cost-benefit ratio (US$0.35/sample).

Synthesis and assessment of CTAB and NPE modified organo-montmorillonite for the fabrication of organo-montmorillonite/alginate based hydrophobic pharmaceutical controlled-release formulation.

The research goal of the present study was to develop a carrier for loading and controlled -release of the hydrophobic drug with the combined use of organo-montmorillonite (OMMT) and alginate. The OMMT was synthesized through the intercalation modification of sodium montmorillonite (Na-MMT) with cationic cetyltrimethylammonium bromide (CTAB), nonionic nonylphenol polyoxyethylene ether (NPE) and the mixture of them via simple and convenient wet ball-milling method. Furthermore, the organo-montmorillonite/alginate (OMMT/Alg) composite hydrogel beads with slow and controlled release properties were constructed by using alginate as a coating material under the exogenous cross-linking of calcium ions. The physical and chemical properties of OMMT were comparatively evaluated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS), thermogravimetric analyzer (TGA), BET-specific surface area measurements, and drug adsorption experiments. Experimental results showed that the presence of CTAB was able to facilitate the intercalation of CTAB/NPE into Na-MMT through the cation exchange reaction. And the cationic CTAB and nonionic NPE were adsorbed or intercalated into the MMT lamellar structure through the wet ball-milling process, which could change the hydrophilic nature of Na-MMT and improve its affinity to the hydrophobic drug molecules. In addition, the OMMT/Alg composite hydrogel beads displayed superior sustained-release properties than Na-MMT/Alg, mainly ascribed to the good affinity of OMMT to hydrophobic drug that retarded the drug diffusion. In particular, CTA/NPE-MMT/Alg with the highest loading capacity (LC) and encapsulation efficiency (EE) revealed the optimal controlled performance for the release of hydrophobic ibuprofen. The release followed the Korsmeyer-Peppas model suggested non-Fickian diffusion release mechanism. Based on the high drug loading capacity and excellent controlled drug release properties, the CTA/NPE-MMT/Alg incorporating hydrophobic drugs into hydrophilic matrices could be a highly promising material for use in hydrophobic drug delivery.

Toxicity assessment of palladium oxide nanoparticles derived from metallosurfactants using multi assay techniques in Allium sativum.

In today's world, nanotechnology is reaching practically every ground and entering the human lifestyle by becoming a part of it. Thus, it is vital to check the cytotoxic and genotoxic effects of nanosubstances on plants, as they are the base constituent of ecosystem. The present work deals with the toxicity evaluation of metallosurfactant derived palladium oxide nanoparticles towards Allium sativum (Garlic cloves). The nanoparticles were prepared using microemulsion quenching method (a softer approach) using palladium metallosurfactants as precursors. The three ligands used were cetyltrimethylammonium chloride (CTAC), dodecylamine (DDA) and hexadecylamine (HEXA). Further, their characterization was done using TEM, Size Distribution curve, FESEM, EDS, XRD and Zeta potential. Garlic (Allium sativum) cloves were used to investigate the cytotoxicity and genotoxicity of fabricated PdO NPs. To check the cytotoxicity, optical microscopy was employed and for the genotoxic assessment, different parameters such as chromosomal aberrations in the mitosis, circular dichroism, and gel electrophoresis were utilized. From mitosis study, chromosomes aberrations were confirmed such as chromosomes stickiness, breakage, C-Mitosis, delay in anaphase, spindle fibre abnormality, laggard, vagrant and condensed chromosomes. Morphology of A. sativum clove, rooting and shooting pattern in the presence of PdO nanosuspension was observed. From all the experiments, it was concluded that all the three PdO nanosuspension are toxic in nature to both the cells and to genome, although, bishexadecyltrimethyl ammonium palladium tetrachloride (PdCTAC) Ns was found to be the most cytotoxic and genotoxic. Gel electrophoresis also confirmed the complete degradation of DNA in the presence of PdCTAC Ns.

An assessment of retention behavior for gold nanorods in asymmetrical flow field-flow fractionation.

Applications of asymmetrical flow field-flow fractionation (AF4) continue to expand rapidly in the fields of nanotechnology and biotechnology. In particular, AF4 has proven valuable for the separation and analysis of particles, biomolecular species (e.g., proteins, bacteria) and polymers (natural and synthetic), ranging in size from a few nanometers to several micrometers. The separation of non-spheroidal structures (e.g., rods, tubes, etc.) with primary dimensions in the nanometer regime, is a particularly challenging application deserving of greater study and consideration. The goal of the present study was to advance current understanding of the mechanism of separation of rod-like nano-objects in the AF4 channel. To achieve this, we have systematically investigated a series of commercially available cetyltrimethylammonium bromide stabilized gold nanorods (AuNRs), with aspect ratios from 1.7 to 10. Results show clearly that the retention time is principally dependent on the translational diffusion coefficient of the AuNRs. Equations used to calculate translational and rotational diffusion coefficients (cylinder and prolate ellipsoid models) yield similarly good fits to experimental data. Well characterized gold nanorods (length and diameter by transmission electron microscopy) can be used as calibrants for AF4 measurements allowing one to determine the aspect ratio of nanorod samples based on their retention times. Graphical abstract ᅟ.

Electrochemical treatment of cetrimonium chloride with boron-doped diamond anodes. A technical and economical approach.

This study presents the results of the electrochemical degradation of the emulsifier cetrimonium chloride (CTAC) on a boron-doped diamond (BDD) anode under different current densities and flow rates. Higher values of these parameters result in a more rapid removal. Nevertheless, operation at low current reduces the required applied charge and increases the chemical oxygen demand (COD) removal efficiency, as there is less development of ineffective parasitic reactions. On the other hand, high flow rates reduce the required volumetric applied charge and increase the COD removal current efficiency. In order to assist and enrich the study, an economic analysis has been performed. For short expected plant lifespans, operation at low current is advantageous due to the lower investment required, whereas for longer expected lifespans, the operational costs make the lower current densities less costly. High flow rates are always advantageous from a financial point of view.

The comparative study of micellar TLC and RP-TLC as potential tools for lipophilicity assessment based on QSRR approach.

Lipophilicity of compound is well known as vital physicochemical property of a molecule, which determines its biological activity. Nonetheless, the assessment of a lipophilicity is still problematic and focuses attention of scientists. Although, the shake-flask method is still considered as a gold standard for experimental determination of lipophilicity, currently the chromatographic approach is mostly used. Among chromatographic methods used for lipophilicity assessment, thin layer chromatography (TLC) is still one of the most popular tools. The main goal of this study was to compare classical reversed-phase thin layer chromatography (RP-TLC) and micellar TLC as potential tools for lipophilicity assessment. Micellar liquid chromatography has significantly lover environment impact than classical reversed-phase liquid chromatography. Additionally comparison of cationic and anionic surfactants (CTAB and SDS), which have different chemical properties, as modifiers of mobile phase in micellar TLC were investigated. The Quantitative Structure-Retention Relationships (QSRR) approach was used in order to present molecular mechanisms of retention in investigated chromatographic systems. The study was based on chemically diverse model set compounds, with a proved therapeutic or toxic potential. According to obtained results the micellar TLC with CTAB as surfactant can be recommended to logP prediction. The obtained QSRR models indicated that adsorption of CTAB monomers on CN modified surface of silica gel and the silanol-quaternary ammonium interactions are possible. Consequently, the reduction of interaction between molecules and free silanol, contributes to the improvement of logP predictions. These result were confirmed by regression and classification methods.

Multiparametric Assessment of Gold Nanoparticle Cytotoxicity in Cancerous and Healthy Cells: The Role of Size, Shape, and Surface Chemistry.

In recent years, we and others have become interested in evaluating the use of surface-enhanced Raman scattering (SERS) tags for early cancer detection and in designing new approaches to demonstrate the applicability of this spectroscopic technique in the clinic. SERS-based imaging in particular offers ultra sensitivity up to the single molecule, multiplexing capability, and increased photostability and has been shown to outperform fluorescence. However, to employ SERS tags for early cancer detection, it is important to understand their interaction with cells and determine their cytotoxicity. We have been particularly interested for quite some time in determining if and how gold nanostars, which have been demonstrated as outstanding SERS enhancing substrates, can be safely employed in living systems and translated to the clinic. In this study, we carried out a multiparametric in vitro study to look at the cytotoxicity and cellular uptake of gold nanoparticles on human glioblastoma and human dermal fibroblast cell lines. Cytotoxicity was evaluated by incubating cells with three different morphologies of AuNPs, namely nanospheres, nanorods, and nanostars, each having three different surface chemistries (cetyltrimethylammonium bromide (CTAB), poly(ethylene glycol) (PEG), and human serum albumin (HSA)). Our results showed that the surface chemistry of the nanoparticles had predominant effects on cytotoxicity, and the morphology and size of the nanoparticles only slightly affected cell viability. CTAB-coated particles were found to be the most toxic to cells, and PEGylated nanostars were determined to be the least toxic. Caspase-3 assay and LDH assay revealed that cell death occurs via apoptosis for cancerous cells and via necrosis for healthy ones. Cellular uptake studies carried out via TEM showed that the particles retain their shape even at long incubation times, which may be beneficial for in vivo SERS-based disease detection. Overall, this study provides valuable information on gold-nanoparticle-induced cytotoxicity that can be leveraged for the development of safe and effective nanoparticle-based therapeutic and diagnostic systems.

Flow-injection chemiluminescence analysis for sensitive determination of atenolol using cadmium sulfide quantum dots.

A sensitive, rapid and simple flow-injection chemiluminescence (CL) system based on the light emitted from KMnO4-cadmium sulfide quantum dots (CdS QDs) reaction in the presence of cetyltrimethylammonium bromide (CTAB) in acidic medium was developed as a CL probe for the sensitive determination of atenolol. Optical and structural features of CdS QDs capped with l-cysteine, which synthesized via hydrothermal approach, were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL), and UV-Vis spectroscopy. The CL intensity of KMnO4-CdS QDs-CTAB was remarkably enhanced in the presence of trace level of atenolol. Under optimum experimental conditions, there is a linear relationship between the increase in CL intensity of KMnO4-CdS QDs-CTAB system and atenolol concentration in a range of 0.001 to 4.0 mg L(-1) and 4.0 to 18.0 mg L(-1), with a detection limit (3σ) of 0.0010 mg L(-1). A possible mechanism for KMnO4-CdS QDs-CTAB-atenolol CL reaction is proposed. To prove the practical application of the KMnO4-CdS QDs-CTAB CL method, the method was applied for the determination of atenolol in spiked environmental water samples and commercial pharmaceutical formulation. Furthermore, corona discharge ionization ion mobility spectrometry (CD-IMS) technique was utilized for determination of atenolol.

A simple, fast, and inexpensive CTAB-PVP-silica based method for genomic DNA isolation from single, small insect larvae and pupae.

In this study, we report a modified CTAB-PVP method combined with silicon dioxide (silica) treatment for the extraction of high quality genomic DNA from a single larva or pupa. This method efficiently obtains DNA from small specimens, which is difficult and challenging because of the small amount of starting tissue. Maceration with liquid nitrogen, phenol treatment, and the ethanol precipitation step are eliminated using this methodology. The A260/A280 absorbance ratios of the isolated DNA were approximately 1.8, suggesting that the DNA is pure and can be used for further molecular analysis. The quality of the isolated DNA permits molecular applications and represents a fast, cheap, and effective alternative method for laboratories with low budgets.

In vitro assessment of antibody-conjugated gold nanorods for systemic injections.

BACKGROUND: The interest for gold nanorods in biomedical optics is driven by their intense absorbance of near infrared light, their biocompatibility and their potential to reach tumors after systemic administration. Examples of applications include the photoacoustic imaging and the photothermal ablation of cancer. In spite of great current efforts, the selective delivery of gold nanorods to tumors through the bloodstream remains a formidable challenge. Their bio-conjugation with targeting units, and in particular with antibodies, is perceived as a hopeful solution, but the complexity of living organisms complicates the identification of possible obstacles along the way to tumors. RESULTS: Here, we present a new model of gold nanorods conjugated with anti-cancer antigen 125 (CA125) antibodies, which exhibit high specificity for ovarian cancer cells. We implement a battery of tests in vitro, in order to simulate major nuisances and predict the feasibility of these particles for intravenous injections. We show that parameters like the competition of free CA125 in the bloodstream, which could saturate the probe before arriving at the tumors, the matrix effect and the interference with erythrocytes and phagocytes are uncritical. CONCLUSIONS: Although some deterioration is detectable, anti-CA125-conjugated gold nanorods retain their functional features after interaction with blood tissue and so represent a powerful candidate to hit ovarian cancer cells.

Shape-directing role of cetyltrimethylammonium bromide in the preparation of silver nanoparticles.

We report a simple chemical reduction method for the synthesis of different colored silver nanoparticles, AgNP, using tyrosine as a reducing agent. Effects of cetyltrimethylammonium bromide, CTAB, and tyrosine concentrations are analyzed by UV-visible measurements and scanning electron microscopy (SEM) to evaluate the mode of AgNP aggregation. The position and shape of the surface resonance plasmon absorption bands strongly depend on the reaction conditions, i.e., [CTAB], [tyrosine], and reaction time. Sub-, post-, and dilution-micellar effects are accountable for the fast and slow nucleation and growth processes. Spectrophotometric measurement also shows that the average size and the polydispersity of AgNP increase with [CTAB] in the solution. CTAB acted as a shape-directing agent.

Assessment of the short-term systemic effect of and acute phase response to mulesing and other options for controlling breech flystrike in Merino lambs.

BACKGROUND: Mulesing is an important method of preventing flystrike of Merino sheep in Australia, but because there are important short-term welfare issues associated with mulesing, alternative methods of removing the skin folds for breech flystrike prevention are being investigated. OBJECTIVE: To examine the short-term systemic effects of mulesing and two proposed alternatives, compared with two control methods, for controlling breech flystrike. METHOD: The five treatment groups comprised 10 lambs each: (1) mulesing, (2) intradermal-cetrimide treatment, (3) clip application, (4) tail docking only and (5) no treatment. Changes in body weight, haematological and biochemical profiles, and concentrations of fibrinogen, haptoglobin and serum amyloid A were measured repeatedly for 29 days post treatment. RESULTS: The mulesing and intradermal-cetrimide groups were the only treatment groups to lose weight during the first week, with greater weight loss in the mulesing group. The mulesing group had the most marked increases in all three acute-phase protein concentrations, closely followed by the intradermal-cetrimide group, with a mild increase observed for the clip group and even less for the tail-docked group. The mulesing group was the only group to develop mild anaemia, transient hyperglycaemia and a persistent decreased albumin : globulin ratio. The neutrophil : lymphocyte ratio was above the upper reference limit for both the mulesing and intradermal-cetrimide groups. CONCLUSION: Mulesing had the greatest systemic effect in terms of the magnitude and duration of increased acute-phase protein concentrations and haematological, biochemical and body weight changes. The clips had a significantly reduced systemic effect compared with mulesing, with the intradermal-cetrimide treatment in between the two. Tail docking had a minimal systemic effect.

BiOBr hierarchical microspheres: Microwave-assisted solvothermal synthesis, strong adsorption and excellent photocatalytic properties.

Two kinds of BiOBr nanosheets-assembled microspheres were successfully prepared via a facile, rapid and reliable microwave-assisted solvothermal route, employing Bi(NO(3))(3)·5H(2)O and cetyltrimethylammonium bromide (CTAB) as starting reagents in the absence or presence of oleic acid. The phase and morphology of the products were characterized by powder X-ray diffraction (XRD), energy dispersive spectrometry (EDS), selected area electron diffraction (SAED), high resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM). Experiments indicated that the formation of these building blocks of microspheres could be ascribed to the self-assembly of nanoparticles according to mesocrystal growth mode. Interestingly, both samples exhibited not only strong adsorption abilities, but also excellent photocatalytic activities for methyl orange (MO), rhodamine B (RhB) and phenol. The resulting BiOBr hierarchical microspheres are very promising adsorbents and photocatalysts for the treatment of organic pollutants.

Detoxification of gold nanorods by conjugation with thiolated poly(ethylene glycol) and their assessment as SERS-active carriers of Raman tags.

We present an effective, low cost protocol to reduce the toxicity of gold nanorods induced by the presence of cetyltrimethylammonium bromide (CTAB) on their lateral surface as a result of the synthesis process. Here, we use thiolated methoxy-poly(ethylene) glycol (mPEG-SH) polymer to displace most of the CTAB bilayer cap from the particle surface. The detoxification process, chemical and structural stability of as-prepared mPEG-SH-conjugated gold nanorods were characterized using a number of techniques including localized surface plasmon resonance (LSPR), transmission electron microscopy (TEM) and surface-enhanced Raman spectroscopy (SERS). In view of future applications as near-infrared (NIR) nanoheaters in localized photothermal therapy of cancer, we investigated the thermal behaviour of mPEG-SH-conjugated gold nanorods above room temperature. We found a critical temperature at around 40 degrees C at which the adsorbed polymer layer is susceptible to undergo conformational changes. Additionally, we believe that such plasmonic nanoprobes could act as SERS-active carriers of Raman tags for application in cellular imaging. In this sense we successfully tested them as effective SERS substrates at 785 nm laser line with p-aminothiophenol (pATP) as a tag molecule.

Biological activity of SDS-CTAB cat-anionic vesicles in cultured cells and assessment of their cytotoxicity ending in apoptosis.

SDS-CTAB cat-anionic vesicles are supramolecular aggregates forming complexes with biopolymers and enter the cells via membrane fusion or endocytosis. Different applicative areas exist: gene therapy, drug delivery and nanotechnology. We previously examined the absorption/release of biopolymers from vesicles in solution. Here we evaluate their cytotoxicity in cultured cells; to this end we characterized the vesicles and analyzed their biological effects at cellular and molecular level. At low concentration these vesicles have scarce consequences on normal cell growth; at higher dosage they activate apoptotic death processes, due to membrane damage. In conclusion, the use of these particles in nano-biotechnology represents an actual possibility.

Non-extraction flow injection determination of cationic surfactants using eriochrome black-T.

A new, rapid, sensitive, non-extraction batch, and flow injection spectrophotometric method for the determination of cationic surfactants (CSs) such as cetyltrimethyl ammonium bromide (CTAB), tetra-n-butyl ammonium chloride (TBAC) and cetylpyridinium chloride (CPC) is proposed. The method is based on the interaction of cationic surfactants with eriochrome black-T to form an ion-association complex. This complex has strong absorbance at 708 nm. The effects of chemical parameters and FIA variables on the determination of cationic surfactants were studied in detail, especially for CTAB. Under optimum conditions, the two linear calibration ranges of the method are 3.0 x 10(-6) to 5.0 x 10(-3)mol L(-1) CTAB, CPB and DTAB for the batch spectrophotometric method and 2.0 x 10(-6) to 2.0 x 10(-4)mol L(-1) CTAB, CPB and TBC for the flow injection spectrophotometric method. The sample throughput was 35+/-5 samples h(-1) at room temperature. The relative standard deviations for 10 replicates of analysis of (2.0, 0.6 and 0.2)x10(-4)mol L(-1) CTAB were 1.2, 1.3, and 0.8%, respectively. In addition, the influence of potential interfering substances on the determination of cationic surfactants was studied. The proposed method is simple and rapid, using no toxic organic solvents. It was applied to the determination of trace CS in industrial wastewater with satisfactory results.

Facile synthesis of polyaniline "sunflowers" with arrays of oriented nanorods.

Polyaniline (PANI) "sunflowers" made of arrays of oriented nanorods were synthesized by chemical oxidative polymerization of aniline in the presence of cetyltrimethylammonium bromide (CTAB) and suitable concentration of HNO3 at about 0 degrees C (ice bath). The reaction conditions, such as the concentration of reagents and reaction temperature were systematically investigated and controlled on the preparation of PANI "sunflowers". The results also suggest that HNO3 probably plays a key role in forming PANI "sunflowers". A possible forming mechanism of the PANI nanostructures is offered.