Tectonomagmatic evolution of Western Amazonia: Geochemical characterization and zircon U-Pb geochronologic constraints from the Peruvian Eastern Cordilleran granitoids

The results of a coupled, in situ laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) U-Pb study on zircon and geochemical characterization of the Eastern Cordilleran intrusives of Peru reveal 1.15 Ga of intermittent magmatism along central Western Amazonia, the Earth's oldest active open continental margin. The eastern Peruvian batholiths are volumetrically dominated by plutonism related to the assembly and breakup of Pangea during the Paleozoic-Mesozoic transition. A Carboniferous-Permian (340-285 Ma) continental arc is identified along the regional orogenic strike from the Ecuadorian border (6 degrees S) to the inferred inboard extension of the Arequipa-Antofalla terrane in southern Peru (14 degrees S). Widespread crustal extension and thinning, which affected western Gondwana throughout the Permian and Triassic resulted in the intrusion of the late- to post-tectonic La Merced-San Ramon-type anatectites dated between 275 and 220 Ma, while the emplacement of the southern Cordillera de Carabaya peraluminous granitoids in the Late Triassic to Early Jurassic (220-190 Ma) represents, temporally and regionally, a separate tectonomagmatic event likely related to resuturing of the Arequipa-Antofalla block. Volcano-plutonic complexes and stocks associated with the onset of the present Andean cycle define a compositionally bimodal alkaline suite and cluster between 180 and 170 Ma. A volumetrically minor intrusive pulse of Oligocene age (ca. 30 Ma) is detected near the southwestern Cordilleran border with the Altiplano. Both post-Gondwanide (30-170 Ma), and Precambrian plutonism (691-1123 Ma) are restricted to isolated occurrences spatially comprising less than 15% of the Eastern Cordillera intrusives. Only one remnant of a Late Ordovician intrusive belt is recognized in the Cuzco batholith (446.5 +/- 9.7 Ma) indicating that the Famatinian arc system previously identified in Peru along the north-central Eastern Cordillera and the coastal Arequipa-Antofalla terrane also existed inboard of this parautochthonous crustal fragment. Hitherto unknown occurrences of late Mesoproterozoic and middle Neoproterozoic granitoids from the south-central cordilleran segment define magmatic events at 691 +/- 13 Ma, 751 +/- 8 Ma, 985 +/- 14 Ma, and 1071-1123 +/- 23 Ma that are broadly coeval with the Braziliano and Grenville-Sunsas orogenies, respectively. Our data suggest the existence of a continuous orogenic belt in excess of 3500 km along Western Amazonia during the formation of Rodinia, its ``early'' fragmentation prior to 690 Ma, and support a model of reaccretion of the Paracas-Arequipa-Antofalla terrane to western Gondwana in the Early Ordovician with subsequent detachment of the Paracas segment in form of the Mexican Oaxaquia microcontinent in Middle Ordovician. A tectonomagmatic model involving slab detachment, followed by underplating of cratonic margin by asthenospheric mantle is proposed for the genesis of the volumetrically dominant Late Paleozoic to early Mesozoic Peruvian Cordilleran batholiths.

Optimization of the procedure for removing iron deposits on ceramic filter media

In this thesis, cleaning of ceramic filter media was studied. Mechanisms of fouling and dissolution of iron compounds, as well as methods for cleaning ceramic membranes fouled by iron deposits were studied in the literature part. Cleaning agents and different methods were closer examined in the experimental part of the thesis. Pyrite is found in the geologic strata. It is oxidized to form ferrous ions Fe(II) and ferric ions Fe(III). Fe(III) is further oxidized in the hydrolysis to form ferric hydroxide. Hematite and goethite, for instance, are naturally occurring iron oxidesand hydroxides. In contact with filter media, they can cause severe fouling, which common cleaning techniques competent enough to remove. Mechanisms for the dissolution of iron oxides include the ligand-promoted pathway and the proton-promoted pathway. The dissolution can also be reductive or non-reductive. The most efficient mechanism is the ligand-promoted reductive mechanism that comprises two stages: the induction period and the autocatalytic dissolution.Reducing agents(such as hydroquinone and hydroxylamine hydrochloride), chelating agents (such as EDTA) and organic acids are used for the removal of iron compounds. Oxalic acid is the most effective known cleaning agent for iron deposits. Since formulations are often more effective than organic acids, reducing agents or chelating agents alone, the citrate¿bicarbonate¿dithionite system among others is well studied in the literature. The cleaning is also enhanced with ultrasound and backpulsing.In the experimental part, oxalic acid and nitric acid were studied alone andin combinations. Also citric acid and ascorbic acid among other chemicals were tested. Soaking experiments, experiments with ultrasound and experiments for alternative methods to apply the cleaning solution on the filter samples were carried out. Permeability and ISO Brightness measurements were performed to examine the influence of the cleaning methods on the samples. Inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis of the solutions was carried out to determine the dissolved metals.

A need for determination of arsenic species at low levels in cereal-based food and infant cereals. Validation of a method by LC-ICPMS.

The present study arose from the need to determine inorganic arsenic (iAs) at low levels in cereal-based food. Validated methods with a low limit of detection (LOD) are required to analyse these kinds of food. An analytical method for the determination of iAs, methylarsonic acid (MA) and dimethylarsinic acid (DMA) in cereal-based food and infant cereals is reported. The method was optimised and validated to achieve low LODs. Ion chromatography-inductively coupled plasma mass spectrometry (LC-ICPMS) was used for arsenic speciation. The main quality parameters were established. To expand the applicability of the method, different cereal products were analysed: bread, biscuits, breakfast cereals, wheat flour, corn snacks, pasta and infant cereals. The total and inorganic arsenic content of 29 cereal-based food samples ranged between 3.7-35.6 and 3.1-26.0 microg As kg-1, respectively. The present method could be considered a valuable tool for assessing inorganic arsenic contents in cereal-based foods.

Standardisation of elemental analytical techniques applied to provenance studies of archaeological ceramics: an inter laboratory calibration study

Chemical analysis is a well-established procedure for the provenancing of archaeological ceramics. Various analytical techniques are routinely used and large amounts of data have been accumulated so far in data banks. However, in order to exchange results obtained by different laboratories, the respective analytical procedures need to be tested in terms of their inter-comparability. In this study, the schemes of analysis used in four laboratories that are involved in archaeological pottery studies on a routine basis were compared. The techniques investigated were neutron activation analysis (NAA), X-ray fluorescence analysis (XRF), inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS). For this comparison series of measurements on different geological standard reference materials (SRM) were carried out and the results were statistically evaluated. An attempt was also made towards the establishment of calibration factors between pairs of analytical setups in order to smooth the systematic differences among the results.

Treatment of pleural malignancies by photo-induction combined to systemic chemotherapy: Proof of concept on rodent lung tumors and feasibility study on porcine chest cavities.

BACKGROUND: Low-dose, Visudyne®-mediated photodynamic therapy (photo-induction) was shown to selectively enhance tumor vessel transport causing increased uptake of systemically administered chemotherapy in various tumor types grown on rodent lungs. The present experiments explore the efficacy of photo-induced vessel modulation combined to intravenous (IV) liposomal cisplatin (Lipoplatin®) on rodent lung tumors and the feasibility/toxicity of this approach in porcine chest cavities. MATERIAL AND METHODS: Three groups of Fischer rats underwent orthotopic sarcoma (n = 14), mesothelioma (n = 14), or adenocarcinoma (n = 12) implantation on the left lung. Half of the animals of each group had photo-induction (0.0625 mg/kg Visudyne®, 10 J/cm(2) ) followed by IV administration of Lipoplatin® (5 mg/kg) and the other half received Lipoplatin® without photo-induction. Then, two groups of minipigs underwent intrapleural thoracoscopic (VATS) photo-induction (0.0625 mg/kg Visudyne®; 30 J/cm(2) hilum; 10 J/cm(2) apex/diaphragm) with in situ light dosimetry in combination with IV Lipoplatin® administration (5 mg/kg). Protocol I (n = 6) received Lipoplatin® immediately after light delivery and Protocol II (n = 9) 90 minutes before light delivery. Three additional animals received Lipoplatin® and VATS pleural biopsies but no photo-induction (controls). Lipoplatin® concentrations were analyzed in blood and tissues before and at regular intervals after photo-induction using inductively coupled plasma mass spectrometry. RESULTS: Photo-induction selectively increased Lipoplatin® uptake in all orthotopic tumors. It significantly increased the ratio of tumor to lung Lipoplatin® concentration in sarcoma (P = 0.0008) and adenocarcinoma (P = 0.01) but not in mesothelioma, compared to IV drug application alone. In minipigs, intrapleural photo-induction combined to systemic Lipoplatin® was well tolerated with no toxicity at 7 days for both treatment protocols. The pleural Lipoplatin® concentrations were not significantly different at 10 and 30 J/cm(2) locations but they were significantly higher in protocol I compared to II (2.37 ± 0.7 vs. 1.37 ± 0.7 ng/mg, P  < 0.001). CONCLUSION: Visudyne®-mediated photo-induction selectively enhances the uptake of IV administered Lipoplatin® in rodent lung tumors. Intrapleural VATS photo-induction with identical treatment conditions combined to IV Lipoplatin chemotherapy is feasible and well tolerated in a porcine model. Lasers Surg. Med. 47:807-816, 2015. © 2015 Wiley Periodicals, Inc.

Emprego de nebulizador pneumático de ICP-MS como câmara de diluição em sistemas de injeção em fluxo para determinações multielementares

An automatic dispenser based on a flow-injection system used to introduce sample and analytical solution into an inductively coupled plasma mass spectrometer through a spray chamber is proposed. Analytical curves were constructed after the injection of 20 to 750 µL aliquots of a multielement standard solution (20.0 µg L-1 in Li, Be, Al, V, Cr, Mn, Ni, Co, Cu, Zn, As, Se, Sr, Ag, Cd, Ba, Tl, Pb) and the acquisition of the integrated transient signals. The linear concentration range could be extended to ca. five decades. The performance of the system was checked by analyzing a NIST 1643d reference material. Accuracy could be improved by the proper selection of the injected volume. Besides good precision (r.s.d. < 2%), the results obtained with the proposed procedure were closer to the certified values of the reference material than those obtained by direct aspiration or by injecting 125 µL of several analytical solutions and samples.

Avaliação da salinização de açudes no semi-árido brasileiro por ICP-AES

The salt accumulation process in some reservoirs of regular and irregular use (from 10 to 50 years of constrution), located in the Southeast of Bahia State was evaluated. Inductively coupled plasma atomic emission spectrometry was used to evaluate the concentrations of Na, K, Ca and Mg in water samples from inside and upstream of the reservoirs. The results showed that for reservoirs of irregular use, the salt accumulation, indicated by the tracer Na, increases with the age of the reservoirs, however for the reservoirs of regular use the hydraulic retention time is the main parameter.

Alternativas analíticas para determinação de ferro e titânio em cimento Portland

In the present work four different analytical methodologies were studied for the determination of iron and titanium in Portland cement. The cement samples were dissolved with hot HCl and HF, being compared Fe and Ti concentrations through four analytical methods: molecular absorption spectrophotometry using the reagents 1,2-hydroxybenzene-3,5-disulfonic acid (Tiron) and the 5-chloro-salicylic acid (CSA), inductively coupled plasma atomic emission spectrometry (ICP-AES) and flame atomic absorption spectrophotometry (FAAS). In the spectrophotometric determinations were studied pH conditions, reagents addition order, interferences, amount of reagents, linear range and stability of the system. In the techniques of ICP-AES and FAAS were studied the best lines, interferences, sensibility and linear range. The obtained results were compared and the agreement was evaluated among the methods for the determination of the metals of interest.

Intervalos de referência para elementos menores e traço em cabelo humano para a população da cidade do Rio de Janeiro - Brasil

Inductively coupled plasma mass spectrometry (ICP-MS) has been used for the determination of twenty minor and trace elements in hair samples from an urban population group (N = 1775), aiming at the establishment of reliable hair reference intervals. Statistical evaluation of the data with respect to age, sex and anatomic region was performed by multivariant analysis and according to recommendations of the International Federation of Clinical Chemistry (IFCC). The results show that mainly age and anatomic region (scalp or pubis) influence significantly the concentration of several elements. Comparison of the here calculated reference intervals with those previously published and used by clinical laboratories for this population showed larger discrepancies and the need for an urgent revision of these data.

A geração química de vapor em espectrometria atômica

The historical development of atomic spectrometry techniques based on chemical vapor generation by both batch and flow injection sampling formats is presented. Detection via atomic absorption spectrometry (AAS), microwave induced plasma optical emission spectrometry (MIP-OES), inductively coupled plasma optical emission spectrometry (ICP-OES) , inductively coupled plasma mass spectrometry (ICP-MS) and furnace atomic nonthermal excitation spectrometry (FANES) are considered. Hydride generation is separately considered in contrast to other methods of generation of volatile derivatives. Hg ¾ CVAAS (cold vapor atomic absorption spectrometry) is not considered here. The current state-of-the-art, including extension, advantages and limitations of this approach is discussed.

Avaliação da padronização interna em espectrometria de absorção atômica utilizando gráficos de correlação

The use of an internal standard (IS) in ET AAS can be considered a new trend after the commercial introduction of a simultaneous spectrometer. The evaluation of experimental data to choose the most appropriate IS can be done by comparing correlation graphs. They were used to verify the resemblance among the simultaneous measurements obtained for the analyte(s) and the IS by inductively coupled plasma optical emission spectrometry (ICPOES). The judicious selection of IS by using correlation graphs for determinations by ET AAS can be exploited to improve the precision and accuracy of the analytical results. Therefore, a new approach for studying the use of IS in ET AAS is presented.

Determinação de manganês em material particulado atmosférico de ambientes de trabalho utilizando eletrodo de diamante dopado com boro e voltametria de onda quadrada com redissolução catódica

A boron-doped diamond electrode is used for determination of Mn(II) in atmospheric particulate matter by square wave cathodic stripping voltammetry. The analytical curve was linear for Mn(II) concentrations between 5.0 and 37.5 µg L-1, with quantification limit of 3.6 µg L-1. The precision was evaluated by the relative standard deviation, with values between 5.1% and 9.3%. The electrode is free of adsorption, minimizing memory effects. Samples collected in the workplace atmosphere of a foundry had Mn(II) concentrations between 0.4 and 4 µg m-3. No significant differences were observed between the proposed method and inductively coupled plasma optical emission spectroscopy.

Classificação de água de coco processada e natural por meio de HCA, PCA e teores de íons metálicos determinados por ICP OES

Inductively Coupled Plasma Optical Emission Spectrometry was used to determine Ca, Mg, Mn, Fe, Zn and Cu in samples of processed and natural coconut water. The sample preparation consisted in a filtration step followed by a dilution. The analysis was made employing optimized instrumental parameters and the results were evaluated using methods of Pattern Recognition. The data showed common concentration values for the analytes present in processed and natural samples. Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) indicated that the samples of different kinds were statistically different when the concentrations of all the analytes were considered simultaneously.

Digestão de óleo lubrificante encapsulado em forno de microondas com radiação focalizada por adição de amostra ao reagente pré-aquecido

The applicability of the recently proposed procedure based on gradual sample addition to microwave-assisted pre-heated concentrated acid is limited by the sample viscosity. In this work, lubricating oil samples with high viscosity were encapsulated and manually added to the microwave-assisted pre-heated concentrated digestion mixture. The procedure was applied for determination of Al, Ca, Cr, Cu, Fe, Mg, Ni, P, Pb, Si, Sn, Sr, V, W, and Zn in lubricating oil by inductively coupled plasma optical emission spectrometry (ICP OES). Determined and certified values for Ca, Mg, P, and Zn in lubricating oil were in agreement at a 95% confidence level.

Mineral and vitamin content of beef, chicken, and turkey hydrolysates mineral and vitamin content of protein hydrolysates

The purpose of this study was to assess the concentration of vitamins and minerals in meat protein hydrolysates. Calcium, phosphorus and iron were analyzed by inductively coupled-plasma atomic emission spectrophotometry; vitamin C was analyzed by the reduction of cupric ions and vitamins B1 and B2 by fluorescence. Regarding minerals, the beef hydrolysate (BH) had more iron than the turkey hydrolysate (TH) and the chicken hydrolysate (CH); TH had a little more phosphorus. BH had the largest amount of vitamin C, and similar amounts of vitamins B1 and B2. The amount of these nutrients found in the hydrolysates suggests that it is possible to use them to enrich special dietary formulations.