Performance of restricted access copper-imprinted poly(allylthiourea) in an on-line preconcentration and sample clean-up FIA-FAAS system for copper determination in milk samples

A new on-line solid phase preconcentration method using an ion-imprinted polymer with restrict access material based on copper-imprinted poly(allylthiourea) modified with 2-hydroxyethyl methacrylate and bovine serum (IIP-HEMA-BSA) to preconcentrate Cu2+ ions and exclude protein from milk samples via FIA-FAAS was developed. The samples were on-line preconcentrated at pH 4.5 through a mini-column packed with 50.0 mg of IIPHEMA-BSA at a flow rate of 7.6 mL min(-1) followed by a counter-current elution with 1.00 mol L-1 HCl towards the FAAS detector. The interference of ions commonly found in milk samples and the presence of BSA were investigated in the Cu2+ ions preconcentration. The method provided an analytical curve ranging from 3.6 to 100.0 mu g L-1, preconcentration factor of 24-fold, limit of detection of 1.1 mu g L-1 and sample throughput of 20 h(-1). The accuracy of the method was attested by Cu2+ ions addition/recovery tests as well as by using GFAAS of samples microwave-assisted digested. The proposed method was successfully applied to the copper determination in milk samples, requiring only pH adjustment followed by preconcentration step as sample pretreatment. Copper content in bovine milk sample was 0.635 +/- 0.042 mg kg(-1), while to soybean milk samples were between 0.048 +/- 0.008 and 0.094 +/- 0.005 mg kg(-1). To the best of our knowledge, the potential of IIP-HEMABSA for Cu2+ ions extraction from biological samples and simultaneous removal of macromolecules employing minimal sample pretreatment was demonstrated for the first time. The proposed extraction method stands out by being simple, fast and a low-cost analytical strategy when compared to the conventional microwave-assisted acid digestion202460CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO ARAUCÁRIA DE APOIO AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO DO ESTADO DO PARANÁ - FAFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP481669/2013-2; 305552/2013-9; 307432/2017-3; 465389/2014-73353/2014; 23038.007082/2014-03163/20142014/50867-

Emprego De Resìduo Agroindustrial (casca De Arroz) Na Remoção De Metais Pesados Em Efluentes Aquosos

EMPREGO DE RESIDUO AGROINDUSTRIAL (CASCA DE ARROZ) NA REMOÇÃO DE METAIS PESADOS EM EFLUENTES AQUOSOS. A casca de arroz, um sub-produto agroindustrial possui em sua composição, macromoléculas com sítios adsortivos capazes de adsorverem metais pesados. A presente invenção refere-se à utilização e avaliação da casca de arroz (Oriza cativa) na remoção de metais pesados contidos em efluentes aquosos. Os efluentes a serem tratados passarão por uma coluna de vidro ou PVC contendo o material adsorvente. O fluxo de tratamento pode ser obtido por gravidade ou controlado por qualquer tipo de bomba. O efluente é considerado tratado quando as concentrações dos metais em solução forem iguais ou inferiores às normas estabelecidas pelo órgão fiscalizador local.BR0302273 (A)C02F1/62C02F1/62BR20030302273C02F1/62C02F1/6

Study On The Performance Of Micro-flow Injection Preconcentration Method On-line Coupled To Thermospray Flame Furnace Aas Using Mwcnts Wrapped With Polyvinylpyridine Nanocomposites As Adsorbent

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)This work describes the synthesis and characterization of a new adsorbent nanocomposite based on multiwalled carbon nanotubes (MWCNTs) and polyvinylpyridine and its use in the development of a highly sensitive micro-flow injection preconcentration method coupled to TS-FF-AAS for the determination of very low levels of Cd. The characterization of the nanocomposite was performed by FT-IR, TGA, SEM, TEM and textural data measurements using the BET and BJH methods. The optimized conditions of the micro-flow injection preconcentration method involved a preconcentrated sample (8.8 mL) at pH 8.0 flowed through 50.0 mg of nanocomposite packed into a mini-column at a flow rate of 4.4 mL min(-1). The on-line elution of Cd(II) ions towards the TS-FF-AAS detector was carried out in countercurrent at a flow rate of 0.6 mL min(-1) using 1.0 mol L-1 HCl. The analytical curve ranged from 0.12 to 6.0 mg L-1 (r = 0.997), and an enhancement factor of 19.5, sample throughput of 15 h(-1) and consumptive index of 0.45 mL were achieved. In terms of sensitivity, the uniquely high adsorption capacity of the nanocomposite was confirmed by the low limit of detection (36 ng L-1) achieved after implementing the preconcentration step in TS-FF-AAS. In terms of selectivity, the proposed method was shown to be tolerable to several foreign ions and applicable to different kinds of waters (tap, mineral, lake, and synthetic seawater), cigarettes, a food sample (powder chocolate), a medicinal herb (Ginkgo biloba) and a certified reference material (fish protein DORM-3).7311929619304Conselho Nacional de Desenvolvimento Cientificoe Tecnologico (CNPq) [481669/2013-2, 305552/2013-9, 472670/2012-3]Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES) [25/2014]Fundacao Araucaria do Parana, Secretaria da CienciaSANEPARLaboratorio de Espectroscopia da Central de Multiusuario da PROPPGInstituto Nacional de Ciencia e Tecnologia de Bioanalitica (INCT) [573672/2008-3]Tecnologia e Ensino Superior do Parana (SETI)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Preparation Of New Ion-selective Cross-linked Poly(vinylimidazole-co-ethylene Glycol Dimethacrylate) Using A Double-imprinting Process For The Preconcentration Of Pb2+ Ions

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)A new ion-selective cross-linked poly(vinylimidazole-co-ethylene glycol dimethacrylate) prepared via a double-imprinting process was developed for the recognition and preconcentration of Pb2+ from water samples. The sorbent was characterized by FT-IR. SEM, TGA and textural data. The maximum dynamic sorption capacity of Pb2+ was 42.04 mg Ph2+ g(-1) of the double-imprinted polymer. The sorption kinetics data were described by a pseudo-second-order model.The double-imprinted polymer exhibited a higher sorption efficiency of Pb2+ than the blank polymer (non-imprinted polymer). The preconcentration procedure involved the loading of a Pb2+ solution at pH 7.25 through 40.0 mg of the double-imprinted polymer packed in a minicolumn at 5.0 mL min(-1). The selective efficiency of proposed method for the Pb2+ preconcentration was assured by competitive sorption using different proportions of Pb2+/cations and Pb2+/anions. An analytical curve was obtained in the range 0.0-300.0 mu g L-1 (r = 0.999) and a limit of detection of 2.46 mu g L-1 was obtained. The preconcentration factor was found to be 21, the consumptive index 0.95 mL and the concentration efficiency 5.25 min(-1). The preconcentration method was successfully applied to the Pb2+ ions determination in different kinds of water samples with high recovery values (91.3-108.9%). (C) 2015 Elsevier Inc. All rights reserved.450254263Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundacao Araucaria do Parana [163/2014]Instituto Nacional de Ciencia e Tecnologia de Bioanalitica (INCT) [573672/2008-3]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Sensitive simultaneous determination of o-nitrophenol and p-nitrophenol in water by surfactant-mediated differential pulse voltammetry

A simple, low-cost and sensitive electroanalytical method was developed for the simultaneous determination of p-nitrophenol and o-nitrophenol isomers in water samples at a glassy carbon electrode (CGE) in the presence of cationic surfactant. The electrochemical behavior of p-nitrophenol and o-nitrophenol was studied by cyclic voltammetry (CV) in 0.1 mol L−1 acetate/acetic acid buffer (pH 3.70) in the presence and absence of cetylpyridinium bromide. The resolution of overlapped cathodic peaks potentials (Epc) of isomers was successfully improved in the presence of 100.0 µmol L−1 cetylpyridinium bromide, thus making this approach ideal for the simultaneous determination of isomers. Under the optimized conditions in 0.05 mol L−1 HEPES buffer at pH 7.0 using differential pulse voltammetry (DPV) at a scan rate of 45 mV s−1, pulse amplitude of 220 mV and modulation time of 10 ms, limits of detection 0.59 µmol L−1 for p-nitrophenol and 1.14 µmol L−1 for o-nitrophenol were obtained with linear ranges from 2.0 to 60.0 µmol L−1 and 3.0 to 60.0 µmol L−1, respectively. The intraday precision was assessed as relative standard deviation (%) for 20.0 and 40.0 µmol L−1 concentrations were 4.30% and 2.41% for p-nitrophenol and 4.87% and 2.20% for o-nitrophenol, respectively. The developed method was applied for the determination of the isomers in lake water samples. The accuracy was attested by comparison with high-performance liquid chromatography with diode array detection (HPLC-DAD) as a reference analytical technique. Recovery values ranging from 90.3% to 111.8% also attested to the accuracy of method for analysis of real samples52914621476CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAIS - FAPEMIG481669/2013-2; 305552/2013-9; 307432/2017-3; 465389/2014-73353/2014; 23038.007082/2014-03163/201

On-line Micro-solid Phase Preconcentration Of Cd2+ Coupled To Ts-ff-aas Using A Novel Ion-selective Bifunctional Hybrid Imprinted Adsorbent

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)A novel hybrid ion imprinted polymer (HIIP) is proposed aiming at the development of an online micro-solid phase preconcentration system of Cd2+ coupled to TS-FF-MS. To evaluate the selective and adsorptive performance of HIIP towards Cd2+, hybrid non-imprinted polymer (HNIP), organic ion imprinted polymer (OIIP), and the inorganic ion imprinted polymer (IIIP) were synthesized and compared with each other. Adsorption capacity of HIIP was 53% higher than HNIP, and dual-site Langmuir-Freundlich isotherm model showed the best fit for data of both polymers. The preconcentration system coupled to TS-FF-MS was performed by loading 10.0 mL of Cd2+ solution at pH 7.5 through 80.0 mg of HIIP packed into a micro-column with posterior online elution using 1.0 mol L-1 HCl/ethanol 1:1 (v/v) mixture. The developed method was highly tolerant for other metal ions Zn2+, Pb2+, Cu2+, Co2+, Fe2+, and Hg2+ at analyte:interferent (1:50, m/m) ratio and Ca2+ and Mg2+ at 1:500 (m/m) ratio. Analytical curve ranging from 0.5 to 7.0 mu g L-1, limit of detection of 30 mu g L-1 and preconcentration factor of 14-fold were obtained. Intra-day and inter-day (3 days) experiment precision (n =10) was, respectively, 3.9 and 0.6% (relative standard deviation, RSD), and 4.4 and 2.4% for concentrations of 0.7 and 6.5 mu g L-1. Sensitivity of method (Abs L mu g(-1)) was about 3.3,2.2 and 1.9-fold higher when compared to preconcentration method using HNIP, OIIP. and IIIP, respectively, thus clearly showing that hybrid polymer and imprinting process enhance Cd2+ adsorption. Addition and recovery experiments ranging from 94 to 106% in mineral, lake water and tap water, urine and cigarette samples attested the feasibility of method for analysis of matrices containing different components. Moreover, the accuracy of method was checked from analysis of certified reference material (DOLT-4, fish liver), being the obtained value of 23.9 +/- 0.6 mg kg(-1) (n = 3) statistically equal to the certified value of 24.3 +/- 0.8 mg kg(-1), by applying Student t-test at 95% confidence level. (C) 2016 Else Vier B.V. All rights reserved.1315769Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) [481669/2013-2, 305552/2013-9, 472670/2012-3]Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES) [25/2014]Fundacao Araucaria do Parana [163/2014]Laborattorio de Espectroscopia da Central de Multiusuario da PROPPG, SANEPAR [09/2014]SETI do ParanaESPEC-UELInstituto Nacional de Ciencia e Tecnologia de Bioanalitica (INCT) [573672/2008-3]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Design of high-performance adsorption cross-linked organic functional polymers towards tricyclic antidepressants using computational simulation

Computational simulations of eighteen functional monomers to produce cross-linked polymers containing high adsorption efficiency to tricyclic antidepressants [amitriptyline (AMT), clomipramine (CLO), doxepin (DOX), imipramine (IMI) and nortriptyline (NOR)] in aqueous medium were evaluated and selected to polymers synthesis. Among them, acrylic acid (AA) and methacrylic acid (MA) were chosen to synthesize the poly(AA-co-EGDMA) and poly(MA-co-EGDMA) adsorbents due to their contrasting calculated interaction energies and to their similar chemical structures. The polymers were characterized by dynamic light scattering (DLS), elemental analysis, swelling effect and textural data. Higher tricyclic antidepressants adsorptions were obtained at pH 7.0 to both polymers, with superior results to poly(AA-co-EGDMA). From the adsorption kinetics the pseudo-second order, Elovich and intraparticle diffusion models showed good adjustments on experimental data of both polymers. The adsorptive predicted by the pseudo-second order model for the poly(AA-co-EGDMA) were 537, 480, 441, 522, 542 mu mol g(-1) to AMT, CLO, DOX, IMI and NOR, respectively, while to poly(MA-co-EGDMA) were 243, 120, 226, 205 and 178 mu mol g(-1). By the thermodynamic parameters, the adsorption process was characterized as endothermic and spontaneous, accompanied by an increase of disorder at the solid-solution interface. The higher adsorption capacity of poly(AA-co-EGDMA) to the antidepressants than to the poly(MA-co-EGDMA) demonstrates agreement with the interaction predicted by the computational simulation, showing its efficiency on predict the best functional monomer to synthesize polymeric adsorbents71CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO ARAUCÁRIA DE APOIO AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO DO ESTADO DO PARANÁ - FA481669/2013-2; 307432/2017-3; 472670/2012-33353/2014; 23038.007082/2014-03163/2014573672/2008-3INSTITUTO NACIONAL DE CIÊNCIA E TECNOLOGIA DE BIOLITÍTICA - INC

<b>Evaluation of DMIT [4,5-Dimercapto-1,3-Dithyol-2-Thionate] as chelating agent in a cloud point extraction procedure for Pb2+ determination in water samples</b> - doi: 10.4025/actascitechnol.v35i2.18076

<p class="aresumo">The present study proposes a new method for cloud point preconcentration of Pb²⁺ ions based on complex formed with [4,5-dimercapto-1,3-dithyol-2-thionate] and posterior determination by flame atomic absorption spectrometry (FAAS). The preconcentration of Pb²⁺ was carried at pH 5.0 under following conditions: time and temperature of batch at 15 min. and 70^oC, respectively, 0.1% (v/v) Triton X-114, 0.003 mol L^-1 acetate/acetic acid buffer solution, 1.0 x 10^-5 mol L^-1 DMIT and 0.5% (m/v) NaCl. Under the best analytical conditions the method provided a limit of detection of 2.85 mg L^-1 by preconcentrating 10.0 mL of sample and calibration curve ranging from 0 up to 650 mg L^-1 (r = 0.99945). The applicability of proposed method for Pb²⁺ determination in natural waters without interferences was checked through addition/recovery tests.</p> <p class="akeyword"> </p

Multivariate optimization and validation of an analytical methodology by RP-HPLC for the determination of losartan potassium in capsules

This paper describes the optimization and validation of an analytical methodology for the determination of losartan potassium in capsules by HPLC using 2(5-1) fractional factorial and Doehlert designs. This multivariate approach allows a considerable improvement in chromatographic performance using fewer experiments, without additional cost for columns or other equipment. The HPLC method utilized potassium phosphate buffer (pH 6.2: 58 mmol L(-1))-acetonitrile (65:35, v/v) as the mobile phase, pumped at a flow rate of 1.0 mL min(-1). An octylsilane column (100 mm x 4.6 mm W., 5 mu m) maintained at 35 degrees C was used as the stationary phase. UV detection was performed at 254 nm. The method was validated according to the ICH guidelines, showing accuracy, precision (intra-day relative standard deviation (R.S.D.) and inter-day R.S.D values <2.0%). selectivity, robustness and linearity (r=0.9998) over a concentration range from 30 to 70 mg L(-1) of losartan potassium. The limits of detection and quantification were 0.114 and 0.420 mg L(-1), respectively. The validated method may be used to quantify losartan potassium in capsules and to determine the stability of this drug. (C) 2009 Elsevier B.V. All rights reserved.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq