Flame atomic absorption spectrometric determination of copper, zinc and manganese after solid-phase extraction using 2,6-dichlorophenyl-3,3-bis(indolyl)methane loaded on Amberlite XAD-16

A simple and selective method for the determination of Cu(2+), Zn(2+) and Mn(2+) ions in real samples by FAAS after solid-phase extraction was developed. The method is based on the sorption of metal ions on Amberlite XAD-16 modified by 3-((2,6-dichlorophenyl)(1H-indol-3-yl)methyl)-1H-indole (DCPIMI) at a pH of 5.0. The metal ions retained on solid phase by complexation with ligand were then eluted with 6 mL of 4 mol L(-1) nitric acid in acetone. In order to obtain a reversible uptake and elution of metal ions, the influence of flow rates of eluent and sample solution, ligand concentration and amount of surfactant and condition of elution solution was also investigated. A preconcentration factor of 225 was achieved by passing 1350 mL of sample through the solid phase, while the limit of detection (LOD) of Cu(2+), Zn(2+) and Mn(2+) ions were found to be 1.9, 1.5 and 2.6 ng mL(-1), respectively, and the corresponding precision at 20 mu g L(-1) was 2.1%, 2.3%, 3.0%. (C) 2010 Elsevier Ltd. All rights reserved

A novel synthesis of tetramethylammonium trioxyfluorochromate(VI)

434-435Reaction between tetramethylammonium fluoride (CH3)4NF and CrO3 in 1:1 molar ratio in the minimum amount of dry acetonitrile gives tetramethylammonium trioxyfluorochromate( VI), (CH3)4NCrO3F in very high yields.The compound has been characterized by elemental analyses and IR spectral studies. The advantages of the new method are discussed

The effects of hydrogen peroxide mouthwashes on the prevention of plaque and gingival inflammation: a systematic review.

Objectives: The purpose of this review was to describe systematically the effects of hydrogen peroxide mouthwashes as an adjunct to daily oral hygiene or as a mono-therapy in the prevention of plaque accumulation and gingival inflammation. Materials and methods: PubMed-MEDLINE and the Cochrane-CENTRAL were searched up to December 2009 to identify appropriate papers. The primary outcome measures included plaque accumulation and parameters of gingivitis. Results: Independent screening of titles and abstracts of 229 articles resulted in 10 publications that met the criteria for eligibility. Descriptive comparisons are presented for hydrogen peroxide mouthwash as compared with control mouthwashes or no oral hygiene. Mean values and standard deviations were obtained by data extraction. Based on a quality assessment, three studies, of which one evaluated H2O2 over a period of 6 months, were considered to represent a low risk of bias. This 6-month study showed a positive effect of the use of H2O2 on the modified gingival index. Conclusions: The results of the studies included in this review showed that H2O2 mouthwashes do not consistently prevent plaque accumulation when used as a short-term mono-therapy. When used as a long-term adjunct to daily oral hygiene, the results of one study indicate that oxygenating mouthwashes reduce gingival redness

Kinetic and equilibrium study of Alizarin Red S removal by activated carbon

Activated carbon has been applied for the adsorption of Alizarin Red S (ARS) from the waste water in a batch method to obtain high removal percentage. The influence of variables such as pH, temperature, ARS concentration, mass and size of adsorbent, and contact time on ARS removal percentage was investigated. Different kinetics, thermodynamics, and isotherm models were applied for fitting the experimental data. The adsorption process follows a pseudo second-order kinetic model with R-2 of 0.98 and Freundlich, Tempkin, and Dubinin-Radushkevich isotherm models with high determination coefficients (R-2) of 0.91, 0.98, and 0.98, respectively. High enthalpy (positive value), Gibbs free energy (negative value), and high entropy values shows the feasibility and the endothermic spontaneous nature of the removal process

The effect of hexetidine mouthwash on the prevention of plaque and gingival inflammation: a systematic review.

To cite this article: Int J Dent Hygiene9, 2011; 182-190 DOI: 10.1111/j.1601-5037.2010.00478.x Afennich F, Slot DE, Hossainian N, Van der Weijden GA. The effect of hexetidine mouthwash on the prevention of plaque and gingival inflammation: a systematic review. Abstract: Objective: To review the literature concerning hexetidine-containing mouthwash as a monotherapy or as an adjunct to oral hygiene in the prevention of plaque accumulation and gingival inflammation. Materials and methods: PubMed-MEDLINE and the Cochrane-CENTRAL were searched through January 2010 to identify appropriate studies. The primary outcome measurements were plaque accumulation and gingivitis parameters. Results: Independent screening of titles and abstracts of 168 papers resulted in six publications that met the eligibility criteria. Mean values and standard deviations were obtained by data extraction. Descriptive comparisons are presented for hexetidine mouthwash and control mouthwashes (chlorhexidine and placebo). Conclusions: Considering the potential benefits in the light of the observed side effects, hexetidine appears to be a poor alternative to chlorhexidine

A novel acorn based adsorbent for the removal of brilliant green

Experiments were carried out to remove brilliant green dye by adsorption technique using a novel adsorbent (activated carbon prepared from acorn). The prepared adsorbent was characterized by BET surface area measurement, FTIR, SEM and elemental analysis. Various parameters such as initial dye concentration, adsorbent dose, initial pH and temperature were studied to observe their effects on the dye adsorption process. At optimum values of the above mentioned parameters, more than 90% removal efficiency was obtained within 30 min at adsorbent dose of 2 g/100 mL for initial dye concentration of 25 mg/L The percentage of dye removal remains almost constant within the pH range of around 6-10. The adsorption of dye was found to follow a pseudo-second-order rate equation. Intra particle diffusion model was studied in order to determine the rate limiting step of the adsorption process. Langmuir isotherm model was fitted the best for the adsorption system with an adsorption capacity of 2.11 mg/g of adsorbent. The present adsorbent may be considered as an alternative adsorbent for the better performance of the brilliant green dye removal from its aqueous medium. (C) 2011 Elsevier B.V. All rights reserved

SDS-coated Sepabeads SP70-modified by 4-[(E)-3-phenylallylidene) amino] benzenethiol as new efficient solid phase for enrichment and determination of copper, nickel, chromium, and zinc ions in soil, plants, and mint water samples

A sensitive and simple method based on modification of Sepabeads SP70 by 4-((E)-3-phenylallylidene) amino) benzenethiol for the simultaneous preconcentration of trace amounts of copper (Cu), nickel (Ni), chromium (Cr), and zinc (Zn) ions in some real samples has been reported. The metal ions which are retained as respective complexes on solid phase were eluted with 8 ml of 4 M nitric acid. The influences of different analytical parameters including pH, ligand amount and Sepabeads SP70 and SDS amount, eluting solutions, and sample volume on metal ions recoveries were investigated. The effects of matrix ions on the retentions of the analytes were also examined. The recoveries of analytes were generally > 95% with RSD between 0.74 and 0.88. The proposed method has been successfully applied for the determination of these metals in some real samples with complex matrices

Activated carbon and multiwalled carbon nanotubes as efficient adsorbents for removal of arsenazo(III) and methyl red from waste water

In this study, removal of arsenazo(III) using activated carbon (AC) and multiwalled carbon nanotubes and of methyl red using AC from waste water is reported. The influences of pH, temperature, concentration of the dye, amount of adsorbents, particle size of adsorbent, and contact time on the efficiency of removal from aqueous solution are investigated. Adsorption experiments indicate that the extent of adsorption is strongly dependent on the pH of the solution. Changes in free energy of adsorption (Delta G(0)), enthalpy (Delta H-0), and entropy (Delta S-0) are calculated to understand the nature of adsorption. The calculated values of Delta G(0) indicate that the adsorption process is spontaneous. The estimated values of Delta H-0 and Delta S-0 are positive which indicates that the adsorption process is endothermic and that the dye molecules are organized on the adsorbent surface in a more random fashion than in solution. The dye adsorption process follows a pseudo-second-order model under involvement of an intra-particle diffusion mechanism. Standard adsorption isotherms are used to fit the experimental data