Synthesis, characterization and application of ion imprinted poly(vinylimidazole) for zinc ion extraction/preconcentration with faas determination

In this paper, we describe the synthesis of an ion imprinted polymer (IIP) by homogeneous polymerization and its use in solid-phase to extract and preconcentrate zinc ions. Under optimal conditions (pH 5.0, preconcentration flow rate of 12.0 mL min-1, and eluted with 1.0 mol L-1 HNO3) this procedure allows the determination of zinc with an enrichment factor of 10.2, and with limits of detection and quantification of 1.5 and 5.0 µg L-1, respectively. The accuracy of our results was confirmed by analysis of tap water and certified reference materials: NIST 1570a (Spinach leaves) and NIST 1515 (Apple leaves)371636

Soybean yield under no-tillage system with an early eleusine coracana fertilization.

The possibility of early soybean fertilization carried out on the predecessor crop has several benefits, mainly operational ones, making the production system more conservationist and balanced. An experiment was carried out at the Anhumas Experimental Station, Luiz de Queiroz College of Agriculture (USP/ESALQ), located in Piracicaba, SP, Brazil, during 2001/2002, 2002/2003, and 2003/2004 agricultural years on a typic Hapludox aiming to evaluate the effects of the early fertilization on soybean yield. The fertilization consisted of applying 90 kg ha?1 of P2O5, 50 kg ha?1 of K2O, and micronutrients (Co, Cu, Fe, Mn, Mo, and Zn). The experiment was conducted in a randomized complete block design with three replications and 12 treatments consisting of different levels of early soybean fertilization carried out on the finger millet crop: T1, no fertilization; T2, conventional soybean fertilization; T3, early 50% K fertilization; T4, early 100% K fertilization; T5, early 50% P fertilization; T6, early 50% P and K fertilization; T7, early 50% P and 100% K fertilization; T8, early 100% P fertilization; T9, early 100% P and 50% K fertilization; T10, early 100% P and K fertilization; T11, early 100% P and K fertilization + micronutrients; and T12, early leaf fertilization with micronutrients. The results showed that the early soybean sowing fertilization with phosphorus and potassium carried out during finger millet sowing does not interfere with the thousand-seed weight and soybean yield

Preparation of a new restricted access molecularly imprinted hybrid adsorbent for the extraction of folic acid from milk powder samples

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)A new hybrid molecularly imprinted polymer (MIP) combined with restricted access (RAM) has been synthesized based on random free-radical polymerization and a sol-gel process. From competitive adsorption studies by using the RAM-MIP and RAM-NIP with folic acid and structurally similar molecules (caffeine, 4-aminobenzamide or paracetamol), relative selectivity coefficients (k) higher than one unit were achieved, indicating good recognition selectivity for folic acid. The percentage of BSA protein exclusion was higher for the RAM-MIP (55.3 + 2.0) as compared to the MIP (35.9 + 2.5%). The solid phase extraction (SPE) procedure was performed by loading the acid extract from milk powder samples previously submitted to saponification and acidification with 10% trichloroacetic acid (TCA) until pH 1.5, through 100 mg of RAM-MIP packed into SPE cartridge. The elution step was carried out by using a mixture of acetonitrile : 0.266 mol L-1 acetate buffer at pH 5.7 (15 : 85, v/v), the same composition of the mobile phase of HPLC. The intra-day precision (n = 10) of the procedure assessed as relative standard deviation (RSD) was 4.7 and 4.1% for the respective concentrations of 20.0 and 150.0 mu g L-1. The applicability of the method was attested by analysis of different brands of milk powder samples fortified with folic acid, as well as by high recovery percentages 95.0-108.4% obtained upon addition and recovery tests. The cleanup process accomplished by RAM-MIP was so efficient that very few remaining matrix components were detected in the eluate by high performance liquid chromatography.A new hybrid molecularly imprinted polymer (MIP) combined with restricted access (RAM) has been synthesized based on random free-radical polymerization and a sol–gel process. From competitive adsorption studies by using the RAM-MIP and RAM-NIP with folic83656665COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO ARAUCÁRIA DE APOIO AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO DO PARANÁ - FACONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)sem informaçãosem informaçãosem informaçãoWe acknowledge the CAPES, INCT-BIOANALITICA, FUNDAÇÃO ARAUCÁRIA do PARANÁ, SETI do Paraná and CNPq for financial support. The authors also would like to thank all the anonymous reviewers for their valuable comments and suggestions to improve the quality

Spectrophotometric Flow-injection System Using Multiwalled Carbon Nanotubes As Solid Preconcentrator For Copper Monitoring In Water Samples

This chapter deals with carbon and carbon nanotubes. Copper is one of a relatively small group of metallic elements that are essential for human, plant, and animal enzymes. Copper ions are introduced into human and animal bodies by food, water, air, etc. Copper enters the marine environment primarily from riverine transport and aerosols. Anthropogenic and geothermal sources can also be included. Depending on its concentration, copper may be a hazard to aquatic organisms. Nanomaterials based on only saturated carbon atoms, also known as carbon nanotubes, in both single-walled carbon nanotubes and multiwalled carbon nanotubes (MWCNTs), are becoming potential sorbents for metal ions due to their unique electronic, mechanical, and chemical properties. The aim of this work is to develop a reliable flow injection preconcentration system coupled to UV-V is molecular spectrophotometry for copper determination using MWCNT as sorbent.This system is the first one that demonstrates the powerful application of MWCNT in the field of solid-phase preconcentration using spectrophotometric determination, a technique naturally less selective than atomic absorption spectrometry. © 2010 Elsevier B.V. All rights reserved.177198(2002) Toxicological profile for copper draft for public comment, , Agency for Toxic Substances and Disease Registry, U.S. Department of Health and Human Services, Public Health Service, Atlanta (GA)Merian, E., Anke, M., Ihnat, M., Stoeppler, M., (2004) Elements and their compounds in the environment, , John Wiley, WeinheimFleming, C.A., Trevors, J.T., Copper toxicity and chemistry in the environment a review (1989) Water Air Soil Pollut, 44, pp. 143-158Tarley, C.R.T., Dos Santos, W.N.L., Dos Santos, C.M., Ferreira, S.L.C., Arruda, M.A.Z., Factorial design and Doehlert matrix in optimization of flow system for preconcentration of copper on polyurethane foam loaded with 4-(2-pyridylazo)-resorcinol (2004) Anal. Letters, 37, pp. 1437-1455de Peña, Y.P., López, W., Burguera, J.L., Burguera, M., Gallignani, M., Brunetto, R., Synthetic zeolites as sorbent material for on-line preconcentration of copper traces and its determination using flame atomic absorption spectrometry (2000) Anal Chim Acta, 403, pp. 249-258Sweileh, J.A., Sorption of trace metals on human hair and application for cadmium and lead pre-concentration with flame atomic absorption determination (2003) Anal Bioanal Chem, 375, pp. 450-455Anthemidis, A.N., Zachariadis, G.A., Farastelis, C.G., Stratis, J.A., On-line liquid-liquid extraction system using a new phase separator for flame atomic absorption spectrometric determination of ultra-trace cadmium in natural waters (2004) Talanta, 62, pp. 437-443Lemos, V.A., Santos, E.S., Santos, M.S., Yamaki, R.T., Thiazolylazo dyes and their application in analytical methods (2007) Microchim Acta, 158, pp. 189-204Akl, M.A., An improved colorimetric determination of lead(II) in the presence of nonionic surfactant (2006) Anal Sci, 22, pp. 1227-1231Bonifácio, V.G., Figueiredo-Filho, L.C., Marcolino Jr, L.H., Fatibello-Filho, O., An improved flow system for chloride determination in natural waters exploiting solid-phase reactor and long pathlength spectrophotometry (2007) Talanta, 72, pp. 663-667Bashammakh, A.S., Bahaffi, S.O., Al-Sibaai, A.A., Al-Wael, H.O., El-Shahawi, M.S., Extractive liquid-liquid spectrophotometric procedure for the determination of thiocyanate ions employing the ion pair reagent amiloride monohydrochloride (2007) Anal Chim Acta, 592, pp. 16-23Figueiredo, E.C., Tarley, C.R.T., Kubota, L.T., Rath, S., Arruda, M.A.Z., On-line molecularly imprinted solid phase extraction for the selective spectrophotometric determination of catechol (2007) Microchem J, 85, pp. 290-296Filik, H., Tayman, A., A new cloud-point preconcentration approach for the spectrophotometric determination of p-aminophenol in the presence of paracetamol with 2-(2-hydroxyphenyl)-1H-benzimidazole as a coupling reagent (2007) J Anal Chem, 62, pp. 530-535Gama, E.M., da Silva Lima, A., Lemos, V.A., Preconcentration system for cadmium and lead determination in environmental samples using polyurethane foam/Me-BTANC (2006) J Hazard Mater, 136, pp. 757-762Bilba, D., Bejan, D., Tofan, L., Chelating sorbents in inorganic chemical analysis (1998) Croat Chem Acta, 71, pp. 155-178Liu, G., Wang, J., Zhu, Y., Zhang, X., Application of multiwalled carbon nanotubes as a solid-phase extraction sorbent for chlorobenzenes (2004) Anal Lett, 14, pp. 3085-3104Liang, P., Shi, T., Jing, L.I., Nanometer-size titanium dioxide separation/preconcentration and FAAS determination of trace Zn and Cd in water sample (2004) Int J Environ Anal Chem, 84, pp. 315-321Hang, C., Hu, B., Jiang, Z., Zhang, N., Simultaneous on-line preconcentration and determination of trace metals in environmental samples using a modified nanometer-sized alumina packed micro-column by flow injection combined with ICP-OES (2007) Talanta, 71, pp. 1239-1245Chiang, I.W., Brinson, B.E., Smalley, R.E., Margrave, J.L., Hauge, R.H., Purification and characterization of single-wall carbon nanotubes (2001) J Phys Chem B, 105, pp. 1157-1161Liang, P., Liu, Y., Guo, L., Zeng, J., Lu, H., Multiwalled carbon nanotubes as solid-phase extraction adsorbent for the preconcentration of trace metal ions and their determination by inductively coupled plasma atomic emission spectrometry (2004) J Anal At Spectrom, 19, pp. 1489-1492Tarley, C.R.T., Barbosa, A.F., Segatelli, M.G., Figueiredo, E.C., Luccas, P.O., Highly improved sensitivity of TS-FF-AAS for Cd(II) determination at ng L-1 levels using a simple flow injection minicolumn preconcentration system with multiwall carbon nanotubes (2006) J Anal At Spectrom, 11, pp. 1305-1313Barbosa, A.F., Segatelli, M.G., Pereira, A.C., Santos, A.S., Kubota, L.T., Luccas, P.O., Solid-phase extraction system of Pb (II) ions enrichment based on multiwall carbon nanotubes couple on-line to flame atomic absorption spectrometry (2007) Talanta, 71, pp. 1512-1519Duran, C., Gundogdu, A., Bulut, V.N., Soylak, M., Elci, L., Sentürk, H.B., Solid-phase extraction of Mn(II), Co(II), Ni(II), Cu(II), Cd(II) and Pb(II) ions from environmental samples by flame atomic absorption spectrometry (FAAS) (2007) J Hazard Mater, 146, pp. 347-355dos Santos, W.N.L., Santos, C.M., Ferreira, S.L.C., Application of three-variables Doehlert matrix for optimisation of an on-line pre-concentration system for zinc determination in natural water samples by flame atomic absorption spectrometry (2003) Microchem J, 75, pp. 211-221Long, G.L., Winefordner, J.D., Limit of detection (1983) Anal Chem, 55, pp. 712-715Yamini, Y., Tamaddon, A., Solid-phase extraction and spectrophotometric determination of trace amounts of copper in water samples (1999) Talanta, 49, pp. 119-124de Moraes, S.V.M., Brasil, J.L., Milcharek, C.D., Martins, L.C., Laranjo, M.T., Gallas, M.R., Use of 1,3-diaminepropane-3-propyl grafted onto a silica gel as a sorbent for flow-injection spectrophotometric determination of copper (II) in digests of biological materials and natural waters (2005) Spectro. Chim. Acta A, 62, pp. 398-406Castilho, E., Cortina, J.L., Beltrán, J.-L., Prat, M.-D., Granados, M., Simultaneous determination of Cd(II), Cu(II) and Pb(II) in surface waters by solid phase extraction and flow injection analysis with spectrophotometric detection (2001) Analyst, 126, pp. 1149-1153Lee, T., Choi, H., Determination and preconcentration of Cu(II) after adsorption of its cupferron onto benzophenone (2002) Bull Korean Chem Soc, 23, pp. 861-864(2005), CONAMA. National Council of Environment. Resolution number 35

Preparation of SiO2/Nb2O5/ZnO mixed oxide by sol-gel method and its application for adsorption studies and on-line preconcentration of cobalt ions from aqueous medium

A new Nb2O5/ZnO mixed oxide dispersed in a silica matrix (i.e., SiO2/Nb2O5/ZnO) was synthesized via sol-gel method and used as an adsorbent of cobalt ions (Co2+). The material presented a high surface area (323 m(2) g(-1)) and the maximum adsorption capacity was found to be 0.518 mg g(-1), determined from the non-linear Langmuir-Freundlich isotherm model. The material was used as a chelating agent free-solid phase extractor (CAF-SPE) in an on-line preconcentration procedure, based on the adsorption of Co2+ ions (16.0 mL, pH 7.4) at a high flow rate (8.0 mL min(-1)) onto a mini-column packed with the adsorbent (200 mg). The analyte was then eluted with 1.0 mol L-1 HCl and transported toward the FAAS detector. Linear calibration range was obtained from 0.96 up to 150.0 mu g L-1, with a limit of detection of 0.281 mu g L-1. The precision of method, estimated as relative standard deviation of ten replicate measurements of 30 and 150 mu g L-1 analyte solutions, was found to be 4.6% and 3.1%, respectively. The reliability of method was verified through the analysis of water and food samples and the accuracy was confirmed by using a certified reference material23923324

Synthesis, characterization and application of ion imprinted poly(vinylimidazole) for zinc ion extraction/preconcentration with faas determination

In this paper, we describe the synthesis of an ion imprinted polymer (IIP) by homogeneous polymerization and its use in solid-phase to extract and preconcentrate zinc ions. Under optimal conditions (pH 5.0, preconcentration flow rate of 12.0 mL min-1, and eluted with 1.0 mol L-1 HNO3) this procedure allows the determination of zinc with an enrichment factor of 10.2, and with limits of detection and quantification of 1.5 and 5.0 µg L-1, respectively. The accuracy of our results was confirmed by analysis of tap water and certified reference materials: NIST 1570a (Spinach leaves) and NIST 1515 (Apple leaves)