Avaliação dos métodos de extração sequencial de Tessier, Keller e Miller na determinação de ferro nativo em três tipos de solos: orgânico, brunizem e latossolo

Sequential extraction is not totally effective to dissolve distinct forms of trace elements. The extractive solution, for example, can dissolve less of the target fraction and more than another not wished fraction. The goal of this work is to compare the extraction of native iron with three sequential extraction methods of the heavy metals, using three soils with different physical chemistry characteristics: a histosol, an oxisol, and a mollisol. The results obtained in this work demonstrate that a smaller relation soil/extractor results in a larger extraction in almost all phases. The use of many stages of the sequential extraction, with the purpose of more association of the metal with different components of the soil, can result, among other things, in modification of the substratum by the action of the reagents used, besides reducing the selectivity of the more specific extractors. Readsorption and redistribution of the heavy metals could have happened with larger intensity in the fraction where hidroxilamine was used with higher temperature. Sequential extraction of iron, without enrichment of soil samples, in the respective fractions in each method, it was important to better understand the behavior of the reagents considered specific to each form of the metal in soil.

Vitaminas lipossolúveis em alimentos: uma abordagem analítica

This study concerns certain problems inherent to the determination of fat-soluble vitamins in food, from extraction methods to identification and quantification. The discussion involves the main official and unofficial extraction methods coupled with spectrophotometric and HPLC techniques in which vitamins samples are obtained through liquid-liquid-solid and liquid-liquid-solid-solid extraction, indispensable to the analytical separation of different chemical compounds with vitamin functions. A saponification stage, possibly coupled with supercritical fluid extraction appears to be mandatory in the determination of vitamins A and E in their alcoholic forms. Alternative identification and quantification procedures are outlined: biological and chemical assays, analytical separations by HPLC (normal and reversed-phase), UV detection (all fat-soluble vitamins) and fluorescence detection (retinoids and tocopherols). Automation from sample preparation to quantification stages increases the data acquisition rate.

Influência do método de extração nos teores de metilxantinas em erva-mate (Ilex paraguariensis a. St.-Hil., aquifoliaceae)

Ilex paraguariensis A. St. -Hil. is a native species of southern South America. The caffeine content in Ilex paraguariensis leaves has been considered an important quality parameter for maté-derived products. In this work different extraction methods for the determination of these methylxantines are compared. The influence of the extraction conditions on the methylxanthine yields was evaluated. Extraction by decoction with acidic aqueous solution (H2SO4 4N) presented the higher efficiency in the theobromine extraction. The extraction in a Soxhlet with acidic aqueous solution and decoction with acidic aqueous solution showed the highest caffeine yield. For the concomitant theobromine and caffeine quantification, the decoction with acidic aqueous solution is suggested.

Hemicellulose extracted Kraft pulp as a raw material of paper

The transformation of a traditional pulp mill into an integrated forest biorefinery utilizing wood-derived biomass presents a promising opportunity for enterprise revival of the pulp and paper industry by offering new sources of revenue and significantly improved industry profitability. One proposed next generation process step for an integrated forest biorefinery is the extraction of hemicelluloses, allowing the co-production of pulp and ethanol or chemicals. The extraction of hemicelluloses, however, will likely have downstream effects on pulp quality. In the literature survey an overview of the integrated forest biorefinery and possible next generation technologies implementable in such facility were reviewed. Moreover, some hemicellulose extraction methods suitable for the co-production of pulp and hemicellulose products were looked into in more detail. Also, an overview on the significance of pulp’s hemicellulose content on papermaking properties of pulp fibers was made. In the literature it is stated that the hemicellulose content of pulp affects on many papermaking properties of pulp fibers, hornification and paper strength properties in particular. In the experimental part the goal was to investigate what effects alkaline hemicellulose extraction after bleaching has on the papermaking properties of birch Kraft pulp. It was discovered that tested pulps, normal and hemi-poor birch Kraft pulp, were different in many ways regarding to pulp properties. Differences were observed in both physical and chemical characteristics. Furthermore, clear distinctions were seen in tested paper properties, especially in strength properties, between the handsheets made from hemi-poor or normal birch Kraft pulp. Hemi-poor and normal birch Kraft pulps were also compared as a raw material of laboratory made copy paper. Based on this comparison, usage of hemi-poor birch pulp as the raw material of copy paper does not drastically deteriorate its quality.

Chumbo e zinco em águas e sedimentos de área de mineração e metalurgia de metais

Lead metallurgy at Adrianópolis is the largest environmental problem of Paraná, Brazil. The objective of this study was to determine Pb and Zn levels in water and sediment in two catchments by different extraction methods. The high levels of lead in water in most of samples do not allow the human use. Total Pb concentration as high as 795.3 µg L-1 was observed in Ribeira River bank, in a pluvial water stream flowering from a abandoned factory. Due to the high Pb levels in sediments from some sites (maximum of 24,300 mg kg-1) is recommended to avoid the water turbulence.

Estudio de la contaminación por metales en sedimentos acuáticos de la Bahía de Matanzas

Surface sediments of the Bay of Matanzas (Cuba) were studied to assess its environmental quality by using several criteria (metal content index, pollution load index and sediment quality guidelines). Two partial digestion sediment procedures and a modified BCR sequential extraction were used. The concentrations of metals were measured by atomic spectroscopy methods. The founded contents of Cu (2,4-27,9 mg kg-1), Zn (2,5-55,5 mg kg-1) and Ni (8,8-99,2 mg kg-1) were below those reported by other authors. The results obtained suggested that the most polluted sites were 3, 5, and 6. The sequential extraction procedure showed that most of the studied metals were associated to the more stable fractions.

Polímeros impressos com íons: fundamentos, estratégias de preparo e aplicações em química analítica

Chemical imprinting technology has been widely used as a valuable tool in selective recognition of a given target analyte (molecule or metal ion), yielding a notable advance in the development of new analytical protocols. Since their discovery, molecularly imprinted polymers (MIPs) have been extensively studied with excellent reviews published. However, studies involving ion imprinted polymers (IIPs), in which metal ions are recognized in the presence of closely related inorganic ions, remain scarce. Thus, this review involved a survey of different synthetic approaches for preparing ion imprinted adsorbents and their application for the development of solid phase extraction methods, metal ion sensors (electrodes and optodes) and selective membranes.

Floculação de Chlorella sp. produzida em concentrado de dessalinização e estudo de método de extração de lipídeos intracelulares

Chlorella sp. was used to assess algal lipid production with concentrated desalination. In order to investigate the action of the flocculating agent calcium chloride and pH, a Box-Behnken Design and a Central Composite Design (CCD) were carried out. Also, Soxhlet and Supercritical Fluid Extraction (SFE), with and without sonication lipid extraction methods, were examined. The optimal flocculation conditions were pH 10.0 and 2.0 g/L of calcium chloride concentration. The highest lipid content of Chlorella sp. was obtained using the Soxhlet extraction method. The most abundant fatty acid extracted by Soxhlet and SFE, with and without sonication, was palmitic acid, whose proportions were 57.4%, 35.3% and 25.5%, respectively.

Otimização e validação da extração sólido-líquido e purificação em baixa temperatura de HPAs em lodo de esgoto

In this study, a method of solid-liquid extraction and purification at low temperature (SLE-PLT) to determine 16 polycyclic aromatic hydrocarbons (PAHs) in sewage sludge was optimized and validated. The analyses were performed by HPLC-UV. The extraction phase, homogenization procedure, influence of pH, ionic strength and clean-up of the extracts were optimized. Recoveries were higher than 63.4% for 11 PAHs. The correlation coefficients were greater than 0.99 and limits of detection and quantitation were less than 0.060 and 0.15 µg g-1, respectively. These values were lower than the maximum residue limits of PAHs established by European legislation. SLE-PLT proved a more practical, economical method with fewer steps compared to Soxhlet extraction (reference method) for PAHs in sewage sludge.

Recovery and refining of manganese as by-product from hydrometallurgical processes

The consumption of manganese is increasing, but huge amounts of manganese still end up in waste in hydrometallurgical processes. The recovery of manganese from multi-metal solutions at low concentrations may not be economical. In addition, poor iron control typically prevents the production of high purity manganese. Separation of iron from manganese can be done with chemical precipitation or solvent extraction methods. Combined carbonate precipitation with air oxidation is a feasible method to separate iron and manganese due to the fast kinetics, good controllability and economical reagents. In addition the leaching of manganese carbonate is easier and less acid consuming than that of hydroxide or sulfide precipitates. Selective iron removal with great efficiency from MnSO4 solution is achieved by combined oxygen or air oxidation and CaCO3 precipitation at pH > 5.8 and at a redox potential of > 200 mV. In order to avoid gypsum formation, soda ash should be used instead of limestone. In such case, however, extra attention needs to be paid on the reagents mole ratios in order to avoid manganese coprecipitation. After iron removal, pure MnSO4 solution was obtained by solvent extraction using organophosphorus reagents, di-(2-ethylhexyl)phosphoric acid (D2EHPA) and bis(2,4,4- trimethylpentyl)phosphinic acid (CYANEX 272). The Mn/Ca and Mn/Mg selectivities can be increased by decreasing the temperature from the commonly used temperatures (40 –60oC) to 5oC. The extraction order of D2EHPA (Ca before Mn) at low temperature remains unchanged but the lowering of temperature causes an increase in viscosity and slower phase separation. Of these regents, CYANEX 272 is selective for Mn over Ca and, therefore, it would be the better choice if there is Ca present in solution. A three-stage Mn extraction followed by a two-stage scrubbing and two-stage sulfuric acid stripping is an effective method of producing a very pure MnSO4 intermediate solution for further processing. From the intermediate MnSO4 some special Mn- products for ion exchange applications were synthesized and studied. Three types of octahedrally coordinated manganese oxide materials as an alternative final product for manganese were chosen for synthesis: layer structured Nabirnessite, tunnel structured Mg-todorokite and K-kryptomelane. As an alternative source of pure MnSO4 intermediate, kryptomelane was synthesized by using a synthetic hydrometallurgical tailings. The results show that the studied OMS materials adsorb selectively Cu, Ni, Cd and K in the presence of Ca and Mg. It was also found that the exchange rates were reasonably high due to the small particle dimensions. Materials are stable in the studied conditions and their maximum Cu uptake capacity was 1.3 mmol/g. Competitive uptake of metals and acid was studied using equilibrium, batch kinetic and fixed-bed measurements. The experimental data was correlated with a dynamic model, which also accounts for the dissolution of the framework manganese. Manganese oxide micro-crystals were also bound onto silica to prepare a composite material having a particle size large enough to be used in column separation experiments. The MnOx/SiO2 ratio was found to affect significantly the properties of the composite. The higher the ratio, the lower is the specific surface area, the pore volume and the pore size. On the other hand, higher amount of silica binder gives composites better mechanical properties. Birnesite and todorokite can be aggregated successfully with colloidal silica at pH 4 and with MnO2/SiO2 weight ratio of 0.7. The best gelation and drying temperature was 110oC and sufficiently strong composites were obtained by additional heat-treatment at 250oC for 2 h. The results show that silica–supported MnO2 materials can be utilized to separate copper from nickel and cadmium. The behavior of the composites can be explained reasonably well with the presented model and the parameters estimated from the data of the unsupported oxides. The metal uptake capacities of the prepared materials were quite small. For example, the final copper loading was 0.14 mmol/gMnO2. According to the results the special MnO2 materials are potential for a specific environmental application to uptake harmful metal ions.

Reaaliaikaisen esikäsittelyn kehittäminen hemiselluloosa-analytiikalle

Tämän työn tavoitteena oli kehittää esikäsittelymenetelmä, jolla voidaan reaaliaikaisesti vähentää hydrolysaatin ligniinipitoisuutta ja näin vähentää fluoresenssia hemiselluloosan analysoimisessa. Työn kirjallisuusosassa käsitellään hemiselluloosien rakennetta sekä niiden erottamista puusta, sekä käydään läpi hemiselluloosien käyttömahdollisuuksia ja niiden reaaliaikaiseen analysointiin soveltuvia tekniikoita. Kokeellisessa osassa tutkittiin ultrasuodatusta sekä adsorptiohartsikäsittelyä hydrolysaatin esikäsittelynä ennen Raman-analyysiä. Esikäsittelyn tavoitteena oli vähentää Raman-analyysia häiritsevää ligniinistä johtuvaa fluoresenssia. Suodatukset tehtiin Amicon-suodatuslaitteistolla käyttäen viittä eri suodatuskalvoa. Hartsikäsittelyissä käytettiin Amberliten XAD16 ja XAD7HP adsorbtiohartseja. Hartsisuhteina käytettiin 1/80, 1/40, 1/19 ja 1/13. Käytetyt ultrauodatuskalvot osoittautuivat suodatusnäytteistä tehtyjen HPLC-analyysien perusteella cut-off-luvultaan liian pieniksi, sillä hemiselluloosien ja ligniinin erotus ei onnistunut, vaan molemmat väkevöityivät konsentraattiin. Hartsikäsittelyillä saatiin ligniiniä poistettua aiheuttamatta hemiselluloosahäviöitä. Parhaimmillaan ligniinin poistumista kuvaava UV-absorbanssi pieneni hartsilla XAD16 37 % ja hartsilla XAD7 25 %. Vaikka ligniinipitoisuus aleni, näytteet fluoresoivat edelleen voimakkaasti Raman-mittauksessa. Tulosten perusteella näyttäisi siltä, että hartsikäsittelyä optimoimalla analyysiä häiritsevää fluoresenssia olisi edelleen mahdollista vähentää.

First identification of natural infection of Rickettsia rickettsii in the Rhipicephalus sanguineus tick, in the State of Rio de Janeiro

The Brazilian Spotted Fever (BSF) is a zoonotic disease caused by Rickettsia rickettsii and transmitted by ticks of the genus Amblyomma, more frequently, Amblyomma cajennense. The aim of this paper was to report the first molecular detection of R. rickettsii on R. sanguineus naturally infected in Rio de Janeiro, Brazil. Ticks were collected from dogs in a rural region of Resende municipality, Rio de Janeiro State, Brazil (22º30'9.46"S, 44º42'44.29"WO), where occurred five human cases of BSF in 2006. The ticks were identified under a stereoscopic microscope and separated in pools by stages, species and sex. DNA extraction was carried out using QIAamp DNA Mini Kit (QIAGEN®). The DNA was submitted to PCR amplification using 04 set of primers: Rr190.70p/Rr190.602n (OmpA, 532bp), BG1-21/BG2-20 (OmpB, 650bp), Tz15/Tz16 (17 kDa protein-encoding gene, 246bp) and RpCS.877p/RpCS.1258n (gltA, 381bp). PCR products were separated by electrophoresis on 1% agarose gels and visualized under ultraviolet light with ethidium bromide. PCR products of the expected sizes were purified by QIAquick® and sequenced by ABI PRISM®. The generated nucleotide sequences were edited with using Bioedit® software and compared with the corresponding homologous sequences available through GenBank, using Discontiguous Mega Blast (http://www.ncbi.nlm.nih.gov). It was confirmed R. rickettsii by sequencing of the material (GenBank FJ356230). The molecular characterization of R. rickettsii in the tick R. sanguineus emphasizes the role of dogs as carriers of ticks from the environment to home. Moreover, this result suggests that there is a considerable chance for active participation of R. sanguineus as one of tick species in the transmission of R. ricketsii to human being in the Brazilian territory.

Anaplasma marginale infection in cattle from south-western Amazonia

The present study provides the first epidemiological data regarding infection by Anaplasma marginale in cattle reared in south-western Brazilian Amazonia. One simple procedure was adapted for the extraction of DNA from blood clots collected in seven microregions of Rondônia State and two mesoregions of Acre State. PCR method was used to asses the frequency of A. marginale infections in 4 to12-month-old cattle. The cattle infection was investigated by polymerase chain reaction (PCR) using the specific primer "msp5" for A. marginale. The DNA amplifications revealed that the mean frequency of A. marginale infection was 98.6% (1,627/1,650) in samples from Rondonia, and 92.87% (208/225) in samples from Acre. The high frequency of A. marginale infections in 4 to 12-month-old cattle indicate a situation of enzootic stability in the studied areas and are comparable to those detected by immunodiagnosis in different endemic regions in Brazil. The DNA extraction of clotted blood method described here can be used for epidemiological studies on anaplasmosis and other bovine hemoparasites.

Polymerase chain reaction for the diagnosis of bovine genital campylobacteriosis

Bovine genital campylobacteriosis is a common venereal disease of cattle; the prevalence of this disease can be underestimated mostly because of the nature of the etiological agent, the microaerobic Campylobacter fetus subspecies venerealis. The purpose of the current study was to evaluate the utilization of polymerase chain reaction (PCR) in the diagnosis of genital campylobacteriosis in samples obtained from bull prepuce aspirate, cow cervical mucus, and abomasum contents of aborted fetuses, collected into enrichment medium. Five different DNA extraction protocols were tested: thermal extraction, lysis with proteinase K, lysis with guanidine isothiocyanate, lysis with DNAzol, and lysis with hexadecyltrimethylammonium bromide (CTAB). The specificity, sensitivity, and technical application of the PCR assay were also evaluated with clinical samples and compared to bacterial isolation by standard culture. DNA extraction by the CTAB protocol provided better results in PCR, and it was able to detect 63 colony-forming units per ml of C. fetus. Out of 277 clinical samples tested, 68 (24%) were positive for Campylobacter fetus using PCR, while only 8 (2.8%) of the samples were positive by bacterial isolation in solid medium, proving the superiority of the PCR technique when compared to the standard isolation method, and providing evidence for its usefulness as a better screening test in cattle for the diagnosis of bovine genital campylobacteriosis.

Mycoplasma agalactiae in semen and milk of goat from Pernambuco state, Brazil

In goat and sheep flocks, mycoplasmosis is a disease that may cause severe economical losses associated with polyarthritis, mastitis, agalactia, conjunctivitis, pneumonia and reproductive failure. The latter may involve repeat breeding, granular vulvovaginitis, infertility and abortions. The aim of the present study was to assess the occurrence of Mycoplasma agalactiae (Ma) in semen and milk samples from naturally infected goat in the semiarid region from Pernambuco State, Northeast from Brazil. Thirty-nine semen samples and 81 milk samples were submitted to DNA extraction using a commercially available kit and following the manufacturer's instructions. The polymerase chain reaction (PCR) was then performed in accordance with protocols described in the literature. The results of the present study revealed the presence of Ma in the DNA of 17.9% (7/39) of the semen samples and 3.7% (3/81) of the milk samples. The results obtained in the present study confirm the elimination of the DNA of Ma in the semen and milk samples. The presence of this agent in goat flocks is considered very risky in terms of reproductive disorders and contagious agalactia outbreaks in the Northeast region of Brazil.