Quantificação de antimônio em garrafas de politereftalato de etileno (PET) brasileiras por fluorescência de raios-X e avaliação quimiométrica para verificar a presença de pet reciclado através do teor de ferro

Antimony is a common catalyst in the synthesis of polyethylene terephthalate used for food-grade bottles manufacturing. However, antimony residues in final products are transferred to juices, soft drinks or water. The literature reports mentions of toxicity associated to antimony. In this work, a green, fast and direct method to quantify antimony, sulfur, iron and copper, in PET bottles by X-ray fluorescence spectrometry is presented. 2.4 to 11 mg Sb kg-1 were found in 20 samples analyzed. The coupling of the multielemental technique to chemometric treatment provided also the possibility to classify PET samples between bottle-grade PET/recycled PET blends by Fe content.

Considerações sobre o preparo de amostras contendo micropoluentes estrogênicos

In this work, the materials used in the recovery of estrogens from aqueous matrices by filtration and solid phase extraction were evaluated. The results showed that glass-fiber filters allow a recovery and repeatability compatible with this type of analysis, whereas cellulose esters lead to significant losses of the analytes, mainly due to adsorption processes. On the other hand, the transferring of the sample to the extraction cartridges should be carried out with glass or Teflon tubing, since the adsorption observed with other polymeric materials (eg. silicone, Tygon, polyethylene and PVC) dramatically reduces the recovery and repeatability of the extraction process.

Determinação de compostos carbonilados e carboxilados em derivados de petróleo

Although metals and nitrogen/sulfur compounds have been the main concern of the petroleum industry, issues concerning the harmful effects on catalysts poisoning and product contamination by other contaminants such as oxygen-containing compounds have been raised. Trace amounts of carbonyl and carboxyl compounds in petroleum products can lead to catalyst poisoning. Additionally, oxygenates may be present in final polyethylene and polypropylene resins, affecting the quality of food packaging. In this work, we reviewed potential analytical approaches for oxygenates determination in petroleum products and report the features of each potential technique.

A reliable method of quantification of trace copper in beverages with and without alcohol by spectrophotometry after cloud point extraction

A new cloud point extraction (CPE) method was developed for the separation and preconcentration of copper (II) prior to spectrophotometric analysis. For this purpose, 1-(2,4-dimethylphenyl) azonapthalen-2-ol (Sudan II) was used as a chelating agent and the solution pH was adjusted to 10.0 with borate buffer. Polyethylene glycol tert-octylphenyl ether (Triton X-114) was used as an extracting agent in the presence of sodium dodecylsulphate (SDS). After phase separation, based on the cloud point of the mixture, the surfactant-rich phase was diluted with acetone, and the enriched analyte was spectrophotometrically determined at 537 nm. The variables affecting CPE efficiency were optimized. The calibration curve was linear within the range 0.285-20 µg L-1 with a detection limit of 0.085 µg L-1. The method was successfully applied to the quantification of copper in different beverage samples.

BIOFILMS BASED ON CANIHUA FLOUR (Chenopodium Pallidicaule): DESIGN AND CHARACTERIZATION

This work aims to (1) produce and characterize the flour obtained from two varieties of canihua, cupi and illpa-inia, and (2) evaluate the ability of these flours to form biofilms. The flours produced contain proteins, starches, lipids, organic substances containing phenol groups, and high percentages of unsaturated fatty acids. Films produced from the illpa variety presented lower water vapor permeability and larger Young’s modulus values than the films formed from the cupi variety. Both films were yellowish and displayed a high light blocking ability (as compared with polyethylene films), which can be attributed to the presence of phenolic compounds. Furthermore, they showed lesser solubility and water permeability than other polysaccharide films, which may be the result of the higher protein (12%–13.8%) and lipid (11%) contents in canihua flours, as well as the formation of a larger number of S–S bonds. On the other hand, these films presented a single vitreous transition temperature at low temperatures (< 0 °C), crystallization of the A and Vh types, and an additional diffraction peak at 2 = 7.5º, ascribed to the presence of essential fatty acids in canihua flour. Canihua flour can form films with adequate properties and shows promise for potential applications in food packaging, because it acts as a good barrier to incident ultraviolet light.

A VERSATILIDADE DOS COMPOSTOS DE COORDENAÇÃO NA PRODUÇÃO DE POLIETILENOS: UMA REVISÃO DOS SISTEMAS CATALÍTICOS

Taking into account the relevance of polyethylene for modern society and the role of catalysts for the production of this material, in the present work, we carried out a review of the main catalytic systems used in industry and academia. Most systems consist of coordination compounds, whose structural versatility allows the tuning of the characteristics of polyethylene for different applications. The structural aspects and chemical reactivity of such systems are discussed based on the existing literature and experimental data.

DEGRADAÇÃO MICROBIOLÓGICA E ENZIMÁTICA DE POLÍMEROS: UMA REVISÃO

Polymer recycling has been one of the most important trend in the petrochemical area. Among different technologies, biotechnological (enzymatic and/or microbial) degradation of polymers for the recovery of monomers and oligomers is environmentally-friendly and meet some green chemistry principles. In this work, conditions for the biotechnological degradation of some industrially-relevant polymers (e.g. poly(ethylene terephthalate) and polyethylene) were revised, and the main biocatalysts were identified. In most cases, biodegradation mechanisms are still unclear, thus being necessary more studies to unravel these promising bioprocesses. Polymer biodegradation studies also present considerable importance for other fields, including biomedical and agricultural.

Survival of Botrytis cinerea as mycelium in rose crop debris and as sclerotia in soil

Botrytis blight caused by Botrytis cinerea is an important disease of rose (Rosa hybrida) grown in greenhouses in Brazil. As little is known regarding the disease epidemiology under greenhouse conditions, pathogen survival in crop debris and as sclerotia was evaluated. Polyethylene bags with petals, leaves, or stem sections artificially infected with B. cinerea were mixed with crop debris in rose beds, in a commercial plastic greenhouse. High percentage of plant parts with sporulation was detected until 60 days, then sporulation decreased on petals after 120 days, and sharply decreased on stems or leaves after 90 days. Sporulation on petals continued for 360 days, but was not observed on stems after 150 days or leaves after 240 days. Although the fungus survived longer on petals, stems and leaves are also important inoculum sources because high amounts of both are deposited on beds during cultivation. Survival of sclerotia produced on PDA was also quantified. Sclerotia germination was greater than 75% in the initial 210 days and 50% until 360 days. Sclerotia weight gradually declined but they remained viable for 360 days. Sclerotia were produced on the buried petals, mainly after 90 days of burial, but not on leaves or stems. Germination of these sclerotia gradually decreased after 120 days, but lasted until 360 days. Higher weight loss and lower viability were observed on sclerotia produced on petals than on sclerotia produced in vitro

Control of tomato bacterial wilt through the incorporation of aerial part of pigeon pea and crotalaria to soil

The use of organic matter that improves the physical, chemical and biological soil properties has been studied as an inducer of suppressiveness to soilborne plant pathogens. The objective of this work was to evaluate the effect of different sources and concentrations of organic matter on tomato bacterial wilt control. Two commercially available organic composts and freshly cut aerial parts of pigeon pea (Cajanus cajan) and crotalaria (Crotalaria juncea) were incorporated, in concentrations of 10, 20 and 30 % (v/v), into soil infested with Ralstonia solanacearum. The soil with the fresh organic matter of pigeon pea and crotalaria was incubated for 30 and 60 days before planting. Tomato seedlings of cv. Santa Clara were transplanted into polyethylene bags with 3 kg of the planting substrate (infested soil + organic matter). The wilting symptoms and percentage of flowering plants were evaluated for 45 days. All evaluated concentrations with incorporation and incubation for 30 days of aerial parts of pigeon pea and crotalaria controlled 100% tomato bacterial wilt. With 60 days of incubation, only the 10 % concentration of pigeon pea and crotalaria did not control the disease. These results suggest that soil incorporation of fresh aerial parts of pigeon pea and crotalaria is an effective method for bacterial wilt control.

Evaluation of alternative containers to determining the working width of fertilizer spreaders

Farmers have difficult of determining the evenness of transverse distribution and the working width, due the tests with this aim require equipments and complex methodologies. So, this study evaluates some alternative containers with the aim to allow a more accessible adjustment of the full width of the solid fertilizer spreaders. Four different containers were tested: i) standard container constructed in accordance with ISO 5690/1; ii) container of polyethylene (plastic trays) with screen shading to prevent the ricochet of material; iii) containers composed by boxes of long-life milk, and iv) containers composed by flowerpots (number 3.5). Also, three different spreaders were used for the tests. Alternative containers showed greater retention of particles than the standardized containers. The full width of work obtained for the coefficients of variation of 12.5; 15; 17.5 and 20%, ranged due the containers in the different pathways. The flowerpots of polyethylene showed similar results to the standardized containers. The heights of the containers were more important for its efficiency than its area of collection.

Substrate with Organosuper® for cucumber seedlings formation in protected environments and polystyrene trays

Culture environments, trays and doses of organic compost were evaluated in the formation of cucumber seedlings (Cucumis sativus L.). Five environmental conditions were tested: (A1) a greenhouse with height of 2.5 m, covered with polyethylene film, (A2) nursery with height of 2.5 m, monofilament fabric, 50% shading, (A3) nursery with height of 2.5 m, heat-reflective screen, 50% shading, (A4) nursery with a height of 1.8 m, covered with coconut tree straw and (A5) greenhouse with height of 4.0 m, covered with polyethylene film, with zenith opening and thermo-reflective cloth under the plastic. Trays of 72 (R1) and 128 (R2) cells were filled with 93% soil and 7% organic compound (S1), 86% soil and 14% organic compound (S2) and 79% soil and 21% organic compound (S3). It was used a randomized design in split-split-plot scheme, with five replicates (environments x trays x substrates). The greenhouses provide the best environments for the formation of cucumber seedlings. A tray of 72 cells is the best container, promoting more vigorous seedlings in substrate with soil and 7 or 14% organic compound.

Potential of adjuvants to reduce drift in agricultural spraying

The reduction of pesticide spraying drift is still one of the major challenges in Brazilian agriculture. The aim of this study was to evaluate the potential of different adjuvant products, such as surfactants, drift retardants, mineral oil and vegetable oil for reducing drift in agricultural spraying. The experiment consisted of quantifying drift of sprayings of 18 adjuvants dissolved in water under controlled conditions in a wind tunnel. Tests were performed in triplicates with spraying nozzles type Teejet XR8003 VK, pressure of 200kPa and medium drops. Solutions sprayed were marked with Brilliant Blue dye at 0.6% (m v-1). The drift was collected using polyethylene strips transversally fixed along the tunnel at different distances from the nozzle and different heights from the bottom part of the tunnel. Drift deposits were evaluated by spectrophotometry in order to quantify deposits. The adjuvants from chemical groups of mineral oil and drift retardant resulted in lower values of drift in comparison with surfactants and water. The results obtained in laboratory show that the selection of appropriate class and concentration of adjuvants can significantly decrease the risk of drift in agricultural spraying. However, the best results obtained in laboratory should be validated with pesticide under field conditions in the future.

Seedlings of Acrocomia aculeata in diferent substrates and protected environments

The seedling production stage is the key to achieve uniformity in tree breeding stage. This study evaluated "bocaiúva" (Acrocomia aculeata) seedling formation, with pre-germinated seeds in different substrates and protected environments, in the University of Mato Grosso do Sul State, Aquidauana, MS. As substrates, we used 100% cattle manure (M), 100% cassava branches (CB), 100% vermiculite (V), 50% cattle manure + 50% cassava branches, 50 % cattle manure + 50% vermiculite, 50% cassava branches + 50% vermiculite and ⅓ cattle manure + ⅓ cassava branches + ⅓ vermiculite. These substrates were tested in a greenhouse covered with 150 µm low density polyethylene (LDPE) film under thermo-reflective screen with 50% shading under film; black screen with 50% shading on the sides; black monofilament screen with 50% shading set on roof and sides; and aluminized thermo- reflective screen with 50% shading set on roof and sides. The completely randomized experimental design with 5 replications of 5 plants each was adopted. Initially, data were submitted to analysis of substrate individual variance in each growing environment, then performing the waste mean square evaluation and their environment joint analysis for comparison. The best growing environment is the thermo-reflective screen compared to LDPE greenhouse and black screen set. All substrates containing manure are recommended for bocaiúva seedlings formation. The pure cassava branch is not indicated for seedling, even using chemical fertilizer.

‘Sweet grape’ tomato post harvest packaging

ABSTRACT This paper aims at evaluating the shelf life of mini tomatoes (Lycopersicum esculentum Mill.) cultivar ‘Sweet Grape’, grown in hydroponics, and stored under environmental and refrigerated conditions inside different packages. We adopted a completely randomized design, in which treatments were combinations of storage conditions: environment (e) and refrigerated (r) with packaging: polyvinyl chloride film (PVC); low-density polyethylene (LDPE); biofilm of tomato fruit of Solanum lycocarpum A.St.-Hil (lobeira) (TFB); cassava starch biofilm (CSB); carnauba wax (Copernicia prunifera) (CW), and without packaging - control (C). Physicochemical and sensory tests were carried out at the beginning (day zero), and at 8, 19, and 33 days of storage (DS). Fruit stored inside PVCr, LDPEe, LDPEr, and CWr had an acceptable shelf life of 33 days. The use of cassava and tomato starches were not effective in controlling fruit fresh weight loss. ‘Sweet Grape’ tomato postharvest conservation was enhanced under refrigerated conditions. The sensory evaluation results revealed that CWr treatment most pleased appraisers, while PCV had the highest rejection rate.

Soursop seedlings: biomasses and biometric relations in different farming environments and substrates – Part II

ABSTRACT The quality of seedling is critical to obtain vigorous plants in the field. The present study aimed to assess biomasses and biometric relations of soursop seedlings. We used different substrates in protected environments. The experiment was performed at the Universidade Estadual do Mato Grosso do Sul (UFMS) (State University of Mato Grosso do Sul). Five farming environments were developed in greenhouses: one covered with low-density polyethylene film (LDPE), another with with polyethylene and heat-reflective cloth under film under 50% shading in aluminized color, monofilament cloth under 50% shading in black, thermo-reflective cloth under 50% shading in aluminized color, and an environment covered with bacuri coconut straw. Substrates were made of manure, humus, cassava branches and vermiculite at different proportions. Each of them varying from 25%, 33.3%, 50% and 75% in mixture combination. Each environment was considered an experiment. A completely randomized design was adopted and later a joint analysis of them. Agricultural greenhouse covered with LDPE and thermo-reflective cloths under 50% of shading, proportionated seedlings with greater biomass. Substrates containing manure are the most suitable for soursop seedlings. High percentages of earthworm humus produce low quality soursop seedlings. Soursop seedlings had a Dickson’s quality index around 0.335. The greenhouse covered only with LDPE film did not produce high quality seedlings.