Influence of biosolids rate on chemical properties of an oxisol in São Paulo, Brazil

Organic residues may cause major health and environmental problems. This is the case in our study area, where more than 10 billion L per year of residential and industrial waste are produced. Land application of biosolids can be an economical solution by recycling waste and can provide valuable fertilizer if used correctly. The aim of this work was to study the effect of biosolids on the chemical properties of an Oxisol. The experiment was located at Ilha Solteira northwest of São Paulo State, Brazil. The soil was cropped to Sorghum bicolor.The field experimental design consisted of random blocks with six treatments and four replications of each treatment. Biosolids were surface applied to four treatments at rates of 5, 10, 20, and 40 Mg ha(-1) on a dry matter basis; in addition, a treatment with mineral fertilizer and a control were included. One year after biosolids application, soil samples were taken at 0-10, 10-20, and 20-40 cm. Organic matter content (Walkley-Black) and pH (CaCl2) were routinely determined. Cation exchange capacity, exchangeable bases (Ca, Mg, K), and P were determined by exchange resin extraction. No significant differences in any of the analyzed properties were found below the 20 cm depth. Extractable phosphorus (P) and potassium (K) increased with increasing biosolids rate in the top 20 cm, whereas calcium (Ca) and (Ma) magnesium content were not significantly influenced by biosolids. Soil pH decreased with increasing biosolids application. The sewage sludge application did not influence the sorghum production in the first year of culture, under unfavorable soil moisture conditions, but it influenced the dry matter.

Determination of aldicarb, aldicarb sulfoxide and aldicarb sulfone in some fruits and vegetables using high-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry

An analytical method for the determination of aldicarb, and its two major metabolites, aldicarb sulfoxide and aldicarb sulfone in fruits and vegetables is described. Briefly the method consisted of the use of a methanolic extraction, liquid-liquid extraction followed by solid-phase extraction clean-up. Afterwards, the final extract is analyzed by liquid chromatography-atmospheric pressure chemical ionization mass spectrometry (LC-APCI-MS). The specific fragment ion corresponding to [M-74](+) and the protonated molecular [M+K](+) ion were used for the unequivocal determination of aldicarb and its two major metabolites. The analytical performance of the proposed method and the results achieved were compared with those obtained using the common analytical method involving LC with post-column fluorescence detection (FL). The limits of detection varied between 0.2 and 1.3 ng but under LC-FL were slightly lower than when using LC-APCI-MS. However both methods permitted one to achieve the desired sensitivity for analyzing aldicarb and its metabolites in vegetables. The method developed in this work was applied to the trace determination of aldicarb and its metabolites in crop and orange extracts. (C) 2000 Elsevier B.V. B.V. All rights reserved.

An alternative methodology for the extraction of humic substances from organic soils

The present study reports on an alternative methodology for the extraction of Humic Substances (HS) from the soil. The extractions were carried out with 0.5 M KOH for 3 h, at a ratio of 1:20 (m/v) under a nitrogen atmosphere. The HS were separated by centrifugation based on their solubility in alcaline solution. This methodology was compared with the usual procedure in three different soil samples and in one sample from vermicompost. The yield, E4/E6 ratio, ash content, and the elemental composition (C, H, O, N) of the extracted HS have been determined. The functional groups were identified by Fourier-transform infrared spectroscopy. This novel procedure adds a new perspective to the extraction of humic substances due to the short time and high performance of the extraction in relation to the usual procedure.

A simple and rapid extraction for gas chromatographic determination of thiabendazole and imazalil residues in lemons

A rapid and efficient method is described for the determination of thiabendazole and imazalil residues in lemons (peel and pulp). The procedure is based on the extraction with an hexane:ethyl acetate mixture (1:1, v/v) and gas chromatographic analysis using thermionic specific detection (TSD). The possibility of matrix effect was also studied. Mean recoveries from 8 replicates of fortified samples ranged from 79% to 109%, with relative standard deviation values between 2.4% to 12.8%. The detection and quantification limits of the method were 0.2 mg kg-1 and 0.5 mg kg-1, respectively.

Development of a supercritical fluid extraction method for simultaneous determination of organophosphorus, organohalogen, organonitrogen and pyretroids pesticides in fruit and vegetables and its comparison with a conventional method by GC-ECD and GC-MS

The aim of this paper was to apply a multiresidue method using Supercritical Fluid Extraction (SFE) and capillary gas chromatography with electron capture and mass spectrometry detections in the analysis of the levels of pesticide residues in fruits and vegetables. Single laboratory validation of both solid-liquid and supercritical fluid extraction methods was carried out for 32 compounds selected from four pesticide classes (organochlorine, organonitrogen, organophosphorus and pyretroid) in blank and fortified samples of fresh lettuce, potato, apple and tomato. Recoveries for the majority of pesticides from fortified samples at fortification level of 0.04-0.10 mg kg -1 ranged 74-96% for both methods and confirmation of pesticide identity was performed by gas-chromatography-mass spectrometry in a selected-ion monitoring mode. Both methods showed good limits of detection (less 0.01 mg kg-1, depending on the pesticide and matrix) and the SFE method minimized environmental concerns, time, and laboratory work. ©2005 Sociedade Brasileira de Química.

Evaluation of the effects of different extraction methods for main volatile compounds from Bambusa textilis leaves

Bambusa textilis is widely used in popular medicine to treat all kinds of wound inflammation, chronic fever, pulmonary and infectious diseases. The aim of this study was to compare the chemical composition of the extracts of B. textilis leaves obtained by three different extraction methods: solid/liquid extraction, Soxhlet and Clevenger system using gas chromatography with flame ionization detector (GC-FID) and gas chromatography with mass spectrometry (GC-MS) analyses. The analytical characteristics of the extracts showed some differences and the GC-MS analysis indicated the presence of higher concentrations of nitro compounds and alkalis. © VSP 2005.

Influence of storage on chemical properties of different peats

The change of chemical properties during storage of 12 fertilized bagged peats of different origins at high temperature was investigated. The average values for N, soluble salts and EC decreased significantly, whereas the pH as well as P and K contents changed only slightly. Differences in N were observed between the peats. The contents of CAT soluble N in the two dredged frozen black peats did not change during storage. However, a decrease in N was found when water extraction was used. In the case of the 10 white peats the loss of N differed considerably, but it was independent of the method of peat harvest. The N decrease resulted mainly from reduced levels of NO3-N. Substances damaging to plant growth do not seem to have developed during storage as shown by trials on the germination and the growth of Chinese cabbage. There were no significant differences between the peats, whether stored or not.

Chemical properties of different peats depending on origin and analytical method

The chemical properties of 12 different peats have been analyzed by methods from VDLUFA (German Association of Agricultural Analysis and Research Institutes) and EN (European Committee for Standardization, Technical Committee 223: Soil improvers and growing media). The analyses of pH (CaCl 2), contents of salts (H 2O), nutrients (CAT), and Na and Cl (H 2O) were carried out by VDLUFA methods, while those of pH (H 2O), EC (H 2O), nutrients (CAT), Na (CAT and H 2O) and Cl (H 2O) according to EN. Ten milled or sod white peats and two dredged frozen black peats of different degrees of decomposition were used. All of them contained high amounts of Mg, while black peats were additionally high in N, Fe and Zn. The pH-values were about the same for all peats. N- and Mn-contents depended most on peat origin. Analytical values of both CAT-methods were in the same range. Extraction with H 2O (EN) as compared to CAT (EN) resulted in considerably lower values.

Yield and phytochemical characterization of essential oil from Ocimum selloi B. obtained by hydrodistillation and supercritical fluid extraction

The yield and chemical composition of essential oils from leaves of Ocimum selloi B. submitted to organic and mineral fertilization, obtained by hydrodistillation and supercritical fluid extraction (SFE) were compared. Essential oil was extracted in a Clevenger-type apparatus for 2 h 30 min and analyzed by GC-MS (Shimadzu, QP 5050-DB-5 capillary column - 30 m × 0.25 mm × 0.25 μm). Carrier gas was helium (1.7 ml/min); split ratio: 1:30. Temperature program: 50°C, rising to 180°C at 5°C/min, 180°C, rising to 280°C at 10°C/min. Injector temperature: 240°C and detector temperature: 230°C. Identifications of chemical compounds were made by matching their mass spectra and Kovat's indices (IK) values with known compounds reported in the literature. An Applied Separations-apparatus (Speed SFE, model 7071, Allentown, PA, EUA) was used for SFE extractions. They were conducted at pressure 200 bar and temperature 30°C (20 min in static mode and 40 min in dynamic mode). The supercritical CO2 flow rate was (6.8±0.7)×10-5 kg-CO2/s. The essential oil collected was immersed in ethylene glycol bath (5°C). The yield of essential oils obtained by SFE was larger than hydrodistillation in both fertilization treatments (279 and 333% for organic and mineral fertilizations, respectively). There were no differences between the fertilization treatments. The amount of the volatile components showed by GC-MS chromatogram was highest in the essential oil obtained by hydrodistillation than SFE. The main volatile constituents of the essential oils were trans-anethole (Hydrodistillation: organic - 52.4%; mineral - 55.0%/ SFE: Hydrodistillation - 62.8%; mineral - 66.8%) and methyl-chavicol (Hydrodistillation: organic - 37.3%; mineral - 38.3%/ SFE: organic - 8.4%; mineral - 4.3%). A reduction of methyl-chavicol relative proportion of essential oil obtained by SFE was observed. Cys-anethole, α-copaene, trans-cariofilene, germacrene-D, β-selinene, biciclogermacrene and spathulenol were expressed only in hydrodistillation. The extraction of essential oil by SFE presented larger yield of essential oil than hydrodistillation technique, presenting, however, these essential oils, different phytochemical profiles.

Chemical alterations of substrate in the cultivation of peppers

The objective of this study was to evaluate the chemical alterations of the substrate in the cultivation of peppers grown in coconut husk fiber, in a protected environment. Initially, 160 pepper plants ('Eppo') were divided into four blocks, where two pots per block were analyzed every 21 days after transplanting. The cultivation of pepper was carried out in plastic pots of 13 L, containing coconut husk fiber, and placed in double rows with a spacing of 0.5×0.8 m between single rows and 1.10 m between double rows. After removal of the plants from the pots, individual samples of substrate (approximately 1 L) were collected from each pot and dried at ambient temperature. The levels of Ca, Mg, S, Cl, Na, B, Fe, Mn, Cu and Zn were determined for all periods of the cultivation. These analyses were performed using the method of extraction 1:1.5 v/v. There was an increase in the levels of all the nutrients evaluated. Further studies should be conducted to develop a better nutrient solution.

A simple, rapid method for the extraction of whole fire ant venom (Insecta: Formicidae: Solenopsis)

The invasive fire ant Solenopsis invicta is medically important because its venom is highly potent. However, almost nothing is known about fire ant venom proteins because obtaining even milligram-amounts of these proteins has been prohibitively challenging. We present a simple and fast method of obtaining whole venom compounds from large quantities of fire ants. For this, we separate the ants are from the nest soil, immerse them in dual-phase mixture of apolar organic solvent and water, and evaporate each solvent phase in separate. The remaining extract from the aqueous phase is largely made up of ant venom proteins. We confirmed this by using 2D gel electrophoresis while also demonstrating that our new approach yields the same proteins obtained by other authors using less efficient traditional methods. © 2013 Elsevier Ltd.

Chemical control of pilea microphylla in euterpe oleraceae nurseries with oxyfluorfen

The açai palm is a Brazilian native species and economically important, grown for the hearts of palm and fruit extraction, as well as the seedling production for ornamental purposes. The weed control is one of the concerns observed in seedling production, which has the artillery plant (Pilea microphylla) with the major and widespread occurrence. Thus, the aim of this trial was to evaluate the selectivity and efficacy of oxyfluorfen in artillery plant control in açai (Euterpe oleracea) seedlings. The experimental design was completely randomized. The treatments were arranged in a 2 x 3 factorial scheme, using 2 types of herbicide application: broadcast spraying (sprayed over total area) and spot spraying (directed to the target) and 3 oxyfluorfen dosages (0, 72 and 144 g of active ingredient ha-1) with four replications. Each experimental unit consisted by one açai palm pot infested by artillery plant. They ere visually evaluated for seedling toxicity and the weed control percentage, at 7, 15, 30, 45 and 60 days after application (DAA). There was 100% control of artillery plant from 15 to 60 DAA for the two tested dosages, regardless of application type. However, 100% control was observed at 7 days, using 1.5 L ha-1 in the spot type. The effects of phytotoxicity from 30 to 60 days was moderate, regardless the application method or dosage.

A mass transfer model applied to the supercritical extraction with CO2 of curcumins from turmeric rhizomes (Curcuma longa L)

ABSTRACT: Increasing restrictions on the use of artificial pigments in the food industry, imposed by the international market, have increased the importance of raw materials containing natural pigments. Of those natural substances with potential applications turmeric rhizomes (Curcuma longa L), are one of the most important natural sources of yellow coloring. Three different pigments (curcumin, desmetoxycurcumin, and bis-desmetoxycurcumin) constitute the curcuminoids. These pigments are largely used in the food industry as substitutes for synthetic dyes like tartrazin. Extraction of curcuminoids from tumeric rhizomes with supercritical CO2 can be applied as an alternative method to obtain curcuminoids, as natural pigments are in general unstable, and hence degrade when submitted to extraction with organic solvents at high temperatures. Extraction experiments were carried out in a supercritical extraction pilot plant at pressures between 25 and 30 MPa and a temperature of 318 K. The influence of drying pretreatment on extraction yield was evaluated by analyzing the mass transfer kinetics and the content of curcuminoids in the extracts during the course of extraction. The chemical identification of curcuminoids in both the extract and the residual solid was performed by spectrophotometry. Mass transfer within the solid matrix was described by a linear first-order desorption model, while that in the gas phase was described by a convective mass transfer model. Experimental results showed that the concentration profile for curcuminoids during the supercritical extraction process was higher when the turmeric rhizomes were submitted to a drying pretreatment at 343 K.

Supercritical extraction of pupunha (Guilielma speciosa) oil in a fixed bed using carbon dioxide

The pupunha (Guilielma speciosa) is the fruit of a palm tree typical of the Brazilian Northern region, whose stem is used as a source of heart of palm. The fruit, which is about 65% pulp, is a source of oil and carotenes. In the present work, an analysis of the kinetics of supercritical extraction of oil from the pupunha pulp is presented. Carbon dioxide was used as solvent. The extractions were carried out at 25 MPa and 323 K and 30 MPa and 318 K. The chemical composition of the extracts in terms of fatty acids was determined by gas chromatography. The amount of oleic acid, a saturated fatty acid, in the CO2 extracts was larger than that in the extract obtained with hexane. The overall extraction curves were modeled using the single-parameter model proposed in the literature to describe the desorption of toluene from activated coal.

Intraspecific variability of Holostylis reniformis: concentration of lignans, as determined by maceration and supercritical fluid extraction (SFE-CO2), as a function of plant provenance and plant parts

Maceration and supercritical fluid extraction were used to prepare extracts from parts of plants (Holostylis reniformis) collected in two different regions of Brazil. ¹H NMR, HPLC-DAD-ESI/MS, HPLC-DAD, GC-MS, and chemometric techniques were used to analyse lignans in the extracts and showed that yields of SFE-CO2 were less than or equal to those of hexane maceration extracts. These analyses, in conjunction with the concentrations of aliphatic hydrocarbons, fatty acids and their methyl and ethyl derivatives in the extracts, also allowed the chemical composition of parts and provenance of the plant to be differentiated.