Comparison of TiO2 nanoparticle and graphene-TiO2 nanoparticle composite phototoxicity to Daphnia magna and Oryzias latipes.

With a dramatic rise in complexity, needs of nanotoxicology research go beyond simple forms of nanomaterials. This study compared the phototoxicity of nano-TiO2 and graphene-TiO2 nanocomposite (GNP). GNP was synthesized based on a hydrothermal method, which simultaneously performed the reduction of graphene oxide and nano-TiO2 loading.

[Effect of Fe and Fe/Ni nanoparticles on the biodegradation of phenol by BFN at different pH values].

Effect of nanoparticles (Fe and Fe/Ni) on the biodegradation of phenol by BFN at different pH values (8.0, 6.0 and 3.

In situ electro-deposition of Pt micro-nano clusters on the surface of {[PMo12O40]3-/PAMAM}n multilayer composite films and their electrocatalytic activities regarding methanol oxidation.

The {[PMo(12)O(40)](3-)/PAMAM}(n) multilayer films are prepared by LBL electrostatic assembly technique, and their uniform and homogeneous traits have been verified by cyclic voltammetry. The {[PMo(12)O(40)](3-)/PAMAM}(n) multilayer films with PAMAM as the outmost layer, having an open structure and exhibiting good penetrability for the solvent molecules at low pH, are used as matrices for electro-deposition of Pt micro-nano clusters in situ. X-ray photoelectron spectroscopy (XPS) analysis and field emission scanning electron microscope (FE-SEM) characterization show that the unique Pt micro-nano clusters with flower-like structure have been immobilized on the surface of {[PMo(12)O(40)](3-)/PAMAM}(n) multilayer films.

Removal of chromium (VI) from wastewater using bentonite-supported nanoscale zero-valent iron.

Bentonite-supported nanoscale zero-valent iron (B-nZVI) was synthesized using liquid-phase reduction. The orthogonal method was used to evaluate the factors impacting Cr(VI) removal and this showed that the initial concentration of Cr(VI), pH, temperature, and B-nZVI loading were all importance factors. Characterization with scanning electron microscopy (SEM) validated the hypothesis that the presence of bentonite led to a decrease in aggregation of iron nanoparticles and a corresponding increase in the specific surface area (SSA) of the iron particles.

Identification of Fe-polycarboxylic complexes by electrospray ionization mass spectrometry and reduction of interferences by ion chromatography/inductively coupled plasma mass spectrometry with an octopole reaction system.

Stable complexes are required during the ion chromatographic (IC) separation of Fe-polycarboxylic acid complexes. Electrospray ionization mass spectrometry (ESI-MS) was used to identify 1:1 stoichiometric complexes of Fe[HEDTA], Fe[EDTA](1-) and Fe[DTPA](2-), and the spectra showed that these Fe complexes were stable in solution. Furthermore, inductively coupled plasma mass spectrometry (ICP-MS) using an octopole reaction system (ORS) reduced polyatomic ion (40)Ar(16)O(+) interference in the detection of (56)Fe via the addition of either H(2) or He to the ORS, with He at a flow rate 3.

Synthesis, characterization and kinetic of a surfactant-modified bentonite used to remove As(III) and As(V) from aqueous solution.

In this study, organobentonites were prepared by modification of bentonite with various cationic surfactants, and were used to remove As(V) and As(III) from aqueous solution. The results showed that the adsorption capacities of bentonite modified with octadecyl benzyl dimethyl ammonium (SMB3) were 0.288 mg/g for As(V) and 0.

Biodegradation of naphthalene by strain Bacillus fusiformis (BFN).

Bacterial strains isolated from oil refining wastewater sludge (Fuzhou, China) were used to biodegrade naphthalene in cultured medium. Bacillus fusiformis (BFN) strain was identified using 16S rDNA gene sequence analysis. Optimal conditions for the biodegradation of naphthalene included: temperature of 30 degrees C, pH 7.

Removal of Pb(II) from aqueous solution using modified and unmodified kaolinite clay.

Modified kaolinite clay with 25% (w/w) aluminium sulphate and unmodified kaolin were investigated as adsorbents to remove Pb(II) from aqueous solution. The results show that amount of Pb(II) adsorbed onto modified kaolin (20mg/g) was more than 4.5-fold than that adsorbed onto unmodified kaolin (4.

Speciation of Zn-aminopolycarboxylic complexes by electrospray ionization mass spectrometry and ion chromatography with inductively coupled plasma mass spectrometry.

The speciation of Zn-aminopolycarboxylic complexes was investigated using both electrospray ionization mass spectrometry (ESI-MS) and ion chromatography (IC) with inductively coupled plasma mass spectrometry (ICP-MS). The resulting ESI mass spectra indicated that [Zn(HEDTA)](1-), [Zn(NTA)](1-), [Zn(EDTA)](2-) and [Zn(DTPA)](3-) were all simultaneously detected in solution; [Zn(NTA)](1-) exhibited the weakest intensity of all these Zn-aminopolycarboxylic complexes. IC/ICP-MS was also successfully used to separate Zn complexes by anion-exchange chromatography using a mobile phase containing 30 mM (NH(4))(2)HPO(4) at pH 7.

A comparative study of the extractability of arsenic species from silverbeet and amaranth vegetables.

There is still no reliable standard extraction method for the speciation of arsenic (As) in plant tissue, and hence there is great interest in developing one for plants that are used as human food. Speciation and bioavailability are critical for accurate human health risk assessment, as As species vary in both their toxicity and bioavailability. Recent incidences of As poisoning in many countries have led to significant research into the fate and dynamics of As in the soil and water environment, including speciation.

Extraction of arsenic species in soils using microwave-assisted extraction detected by ion chromatography coupled to inductively coupled plasma mass spectrometry.

We have developed a novel microwave-assisted extraction method for determining the arsenic (As) speciation in soils that is based on extraction with phosphate solutions, including orthophosphoric acid, ammonium dihydrogen orthophosphate, and ammonium hydrogen orthophosphate. The highest extracting efficiency was obtained with 1 M ortho-phosphoric acid solution as the extractant, and this efficiency is associated with the pH of the extractant. Total As content and As species in the soil extracts were determined by inductively coupled plasma mass spectrometry (ICP-MS) alone and by the combined ion chromatography (IC) with ICP-MS, respectively.

2,4,6-Trinitrotoluene reduction kinetics in aqueous solution using nanoscale zero-valent iron.

The reduction of 2,4,6-trinitrotoluene (TNT) in aqueous solution using nanoscale zero-valent iron (nZVI) was investigated. The results showed that the pseudo-first order reaction law fit the reduction of TNT. The measured apparent rate constant (K(obs)) of TNT on nZVI (0.

Speciation of metal-EDTA complexes by flow injection analysis with electrospray ionization mass spectrometry and ion chromatography with inductively coupled plasma mass spectrometry.

Flow injection analysis (FIA) with ESI-MS and ion chromatography (IC) with inductively coupled plasma-MS (ICP-MS) as the complementary technique have been explored for the determination of metal ions as their metal-EDTA complexes. ESI-MS enabled the identification of metal-EDTA complexes such as [Mn(EDTA)](2-), [Co(EDTA)](2-), [Ni(EDTA)](2-), [Cu(EDTA)](2-), [Zn(EDTA)](2-), [Pb(EDTA)](2-), and [Fe(EDTA)](1-) and their MS spectral showed that these metal-EDTA complexes were present in solution. Based on the ESI-MS, ion chromatographic separation and ICP-MS detection of these complexes are possible because IC-ICP-MS requires stable metal-EDTA complex during the chromatographic separation.

Trends in speciation analysis of vanadium in environmental samples and biological fluids--a review.

A comprehensive review is presented addressing recent trends in the speciation and determination of vanadium in environmental and biological sample matrices, including important analytical aspects such as sample clean up, pre-concentration and method development. Methodology based on both separation and spectroscopic techniques for the determination of vanadium speciation is discussed. A brief outline of analytical principles, together with an overview of the recent developments and applications of vanadium speciation determination is included.

Confirmation of lead aminocarboxylic complex formation using electrospray ionization mass spectrometry and speciation by anion-exchange chromatography coupled with ICP-MS.

Inductively coupled plasma mass spectrometry (ICP-MS) and electrospray ionization mass spectrometry (ESI-MS) were used as complementary techniques to provide element and molecular information for aminocarboxylic lead species including [Pb(NTA)]1-, [Pb(HEDTA)]1-, [Pb(EDTA)]2- and [Pb(DTPA)]3-. ESI-MS was used to initially confirm the formation of lead aminocarboxylic complexes in solution and subsequently anion-change chromatography coupled with ICP-MS was used to speciate these complexes using a mobile phase containing 30 mM NH4H2PO4 at pH of 8.0.

Speciation of iodate and iodide in seawater by non-suppressed ion chromatography with inductively coupled plasma mass spectrometry.

A non-suppressed ion chromatography (IC) with inductively coupled plasma mass spectrometry (ICP-MS) has been developed for simultaneous determination of trace iodate and iodide in seawater. An anion-exchange column (G3154A/101, provided by Agilent) was used for the separation of iodate and iodide with an eluent containing 20mM NH(4)NO(3) at pH 5.6, which reduced the build-up of salts on the sampler and skimmer cones.

Confirmation of vanadium complex formation using electrospray mass spectrometry and determination of vanadium speciation by sample stacking capillary electrophoresis.

Capillary zone electrophoresis (CZE) with UV detection was used to determine vanadium species. Nitrilotriacetic acid (NTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), ethylene glycol-bis(2-aminoethylether)-tetraacetic acid (EGTA) and 2,6-pyridinedicarboxylic acid (PDCA) were investigated to determine whether these ligands formed stable anionic complexes with vanadium. Of all the ligands studied HEDTA was the most suitable ligand because it gave the largest UV response with reasonable migration time.

Speciation of arsenic by ion chromatography inductively coupled plasma mass spectrometry using ammonium eluents.

A method based on ion chromatography (IC) and inductively coupled plasma MS (ICP-MS) was developed for the speciation of arsenic in water and soil extracts. An anion-exchange column (G3154A/101) was used to separate As(III), As(V), dimethylarsinic acid (DMA), and monomethylarsonic acid (MMA) with excellent resolution. Various ammonium salts, including NH4H2PO4, (NH4)2HPO4, (NH4)2CO3, and NH4HCO3, were examined as eluents to reduce matrix interference from chloride and to solve clogging problems.

On-column complexation capillary electrophoretic separation of Fe2+ and Fe3+ using 2,6-pyridinedicarboxylic acid coupled with large-volume sample stacking.

On-column complexation of Fe2+ and Fe3+ with 2,6-pyridinedicarboxylic acid (2,6-PDCA) formed anionic complexes, which were then separated by capillary zone electrophoresis with direct UV detection at 214 nm. To achieve reasonable separation selectivity and on-column complexation, the conditions such as pH, the concentration of 2,6-PCDA and the EOF modifiers in the electrolyte were examined. The electrolyte contained 5.

Preconcentration using diethylenetriaminetetraacetic acid-functionalized polysiloxane (DETAP) for determination of molybdenum(VI) in seawater by ICP-OES.

This paper reports a new method for preconcentration and separation of trace amounts of molybdenum in seawater samples prior to determination by inductively coupled plasma-atomic emission spectroscopy (ICP-OES). Diethylenetriaminetetraacetic acid-functionalized polysiloxane (DETAP) was synthesized by carboxymethylation of amino groups on triamine immobilized polymer, which was prepared by modification of 3-chloropropylpolysiloxane with diethylenetriamine. The resulting polysiloxane is highly selective and efficient in chelating Mo(VI) at trace levels.

Separation of arsenic species by capillary electrophoresis with sample-stacking techniques.

A simple capillary zone electrophoresis procedure was developed for the separation of arsenic species (AsO(2)(2-), AsO(4)(2-), and dimethylarsinic acid, DMA). Both counter-electroosmotic and co-electroosmotic (EOF) modes were investigated for the separation of arsenic species with direct UV detection at 185 nm using 20 mmol L(-1) sodium phosphate as the electrolyte. The separation selectivity mainly depends on the separation modes and electrolyte pH.

Enhanced selectivity and sensitivity for inorganic anions using an ion-pairing reagent and sample stacking in capillary zone electrophoresis with direct UV detection.

In this paper, the use of an ion-pairing reagent to improve the separation selectivity of inorganic anions in CZE was demonstrated by the addition of tetramethylammonium hydroxide (TMAOH) to the electrolyte. The separation of inorganic anions (Cl(-), I(-), Br(-), NO(2)(-), NO(3)(-) and SCN(-)) was performed using co-electroosmotic flow (EOF) with direct UV detection at 185 nm. The parameters affecting the mobility of the tested anions and the EOF such as the electrolyte pH and concentration of TMAOH in the electrolyte were examined to optimise the separation conditions.

On-column complexation and simultaneous separation of vanadium(IV) and vanadium(V) by capillary electrophoresis with direct UV detection.

An on-column complexation method has been developed for the simultaneous determination of V(IV) and V(V). Vanadium species were chelated with aminopolycarboxylic acids to form anionic complexes which were separated by capillary zone electrophoresis (CZE) with direct UV detection. Ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentacetric acid (DTPA), nitrilotriacetic acid (NTA), and N-2-hydroxyethylethlendiaminetriacetric acid (HEDTA) were investigated as both ligand and running electrolyte.