Sample records for diphenylcarbazones

  1. Synthesis and characterisation of nano structure lead (II) ion-imprinted polymer as a new sorbent for selective extraction and preconcentration of ultra trace amounts of lead ions from vegetables, rice, and fish samples.

    Behbahani, Mohammad; Bagheri, Akbar; Taghizadeh, Mohsen; Salarian, Mani; Sadeghi, Omid; Adlnasab, Laleh; Jalali, Kobra


    This paper describes the preparation of new Pb(II)-imprinted polymeric particles using 2-vinylpyridine as a functional monomer, ethylene glycol dimethacrylate as the cross-linker, 2,2'- azobisisobutyronitrile as the initiator, diphenylcarbazone as the ligand, acetonitril as the solvent, and Pb(NO(3))(2) as the template ion, through bulk polymerisation technique. The imprinted lead ions were removed from the polymeric matrix using 5 mL of HCl (2 mol.L(-1)) as the eluting solvent. The lead ion concentration was determined by flame atomic absorption spectrometry. Optimum pH for maximum sorption was obtained at 6.0. Sorption and desorption of Pb(II) ions on the IIP particles were quite fast and achieved fully over 5 min. In the proposed method, the maximum sorbent capacity of the ion-imprinted polymer was calculated to be 75.4 mg g(-1). The preconcentration factor, relative standard deviation, and limit of detection of the method were found to be 245, 2.1%, and 0.42 ng mL(-1), respectively. The prepared ion-imprinted polymer particles have an increased selectivity toward Pb(II) ions over a range of competing metal ions with the same charge and similar ionic radius. This ion-imprinted polymer is an efficient solid phase for extraction and preconcentration of lead ions in complex matrixes. For proving that the proposed method is reliable, a wide range of food samples with different and complex matrixes was used.

  2. Modified hydrothermal synthesis and characterization of reduced graphene oxide-silver selenide nanocomposites with enhanced reactive oxygen species generation

    Lei Zhu; Shu Ye; Asghar Ali; Kefayat Ulla; Kwang Youn Cho; Won-Chun Oh


    A visible‐light photocatalyst containing Ag2Se and reduced graphene oxide (RGO) was synthesized by a facile sonochemical‐assisted hydrothermal method. X‐ray diffraction, scanning electron mi‐croscopy with energy‐dispersive X‐ray analysis, and ultraviolet‐visible diffuse reflectance spectros‐copy results indicated that the RGO‐Ag2Se nanocomposite contained small crystalline Ag2Se nano‐particles dispersed over graphene nanosheets and absorbed visible light. The high crystallinity of the nanoparticles increased photocatalytic activity by facilitating charge transport. N2 adsorp‐tion‐desorption measurements revealed that the RGO‐Ag2Se nanocomposite contained numerous pores with an average diameter of 9 nm, which should allow reactant molecules to readily access the Ag2Se nanoparticles. The RGO‐Ag2Se nanocomposite exhibited higher photocatalytic activity than bulk Ag2Se nanoparticles to degrade organic pollutant rhodamine B and industrial dye Texbrite BA‐L under visible‐light irradiation (λ>420 nm). The generation of reactive oxygen spe‐cies in RGO‐Ag2Se was evaluated through its ability to oxidize 1,5‐diphenylcarbazide to 1,5‐diphenylcarbazone. The small size of the Ag2Se nanoparticles in RGO‐Ag2Se was related to the use of ultrasonication during their formation, revealing that this approach is attractive to form po‐rous RGO‐Ag2Se materials with high photocatalytic activity under visible light.

  3. A novel solid phase extraction procedure on Amberlite XAD-1180 for speciation of Cr(III), Cr(VI) and total chromium in environmental and pharmaceutical samples.

    Narin, Ibrahim; Kars, Ayse; Soylak, Mustafa


    Due to the toxicity of chromium, species depend on their chemical properties and bioavailabilities, speciation of chromium is very important in environmental samples. A speciation procedure for chromium(III), chromium(VI) and total chromium in environmental samples is presented in this work, prior to flame atomic absorption spectrometric determination of chromium. The procedure is based on the adsorption of Cr(III)-diphenylcarbazone complex on Amberlite XAD-1180 resin. After oxidation of Cr(III), the developed solid phase extraction system was applied to determinate the total chromium. Cr(III) was calculated as the difference between the total Cr content and the Cr(VI) content. The analytical conditions for the quantitative recoveries of Cr(VI) on Amberlite XAD-1180 resin were investigated. The effects of some alkaline, earth alkaline, metal ions and also some anions were also examined. Preconcentration factor was found to be 75. The detection limits (LOD) based on three times sigma of the blank (N: 21) for Cr(VI) and total chromium were 7.7 and 8.6 microg/L, respectively. Satisfactory results for the analysis of total chromium in the stream sediment (GBW7310) certified reference material for the validation of the presented method was obtained. The procedure was applied to food, water and pharmaceutical samples successfully.

  4. A microfluidic paper-based analytical device for rapid quantification of particulate chromium

    Rattanarat, Poomrat [Electrochemistry and Optical Spectroscopy Research Unit (EOSRU), Department of Chemistry, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok 10330 (Thailand); Dungchai, Wijitar [Department of Chemistry, Faculty of Science, King Mongkut' s University of Technology Thonburi, 91 Prachautid Road, Thungkru, Bangkok 10140 (Thailand); Cate, David M. [School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523 (United States); Siangproh, Weena [Department of Chemistry, Faculty of Science, Srinakharinwirot University, Sukhumvit 23, Wattana, Bangkok 10110 (Thailand); Volckens, John, E-mail: [Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523 (United States); Chailapakul, Orawon, E-mail: [Electrochemistry and Optical Spectroscopy Research Unit (EOSRU), Department of Chemistry, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok 10330 (Thailand); National Center of Excellence for Petroleum, Petrochemicals and Advanced Materials, Chulalongkorn University, Patumwan, Bangkok 10330 (Thailand); Henry, Charles S., E-mail: [School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523 (United States); Department of Chemistry, Colorado State University, Fort Collins, CO 80523 (United States)


    Graphical abstract: -- Highlights: •Cr detection using a paper-based analytical device. •Analysis of total Cr levels in particulate matter was achieved. •Method for on-paper oxidation of Cr to Cr(VI) using Ce(IV) was established. -- Abstract: Occupational exposure to Cr is concerning because of its myriad of health effects. Assessing chromium exposure is also cost and resource intensive because the analysis typically uses sophisticated instrumental techniques like inductively coupled plasma-mass spectrometry (ICP-MS). Here, we report a novel, simple, inexpensive microfluidic paper-based analytical device (μPAD) for measuring total Cr in airborne particulate matter. In the μPAD, tetravalent cerium (Ce(IV)) was used in a pretreatment zone to oxidize all soluble Cr to Cr(VI). After elution to the detection zone, Cr(VI) reacts with 1,5-diphenylcarbazide (1,5-DPC) forming 1,5-diphenylcarbazone (DPCO) and Cr(III). The resulting Cr(III) forms a distinct purple colored complex with the DPCO. As proof-of-principle, particulate matter (PM) collected on a sample filter was analyzed with the μPAD to quantify the mass of total Cr. A log-linear working range (0.23–3.75 μg; r{sup 2} = 0.998) between Cr and color intensity was obtained with a detection limit of 0.12 μg. For validation, a certified reference containing multiple competing metals was analyzed. Quantitative agreement was obtained between known Cr levels in the sample and the Cr measured using the μPAD.