Ökologische Gruppierung von Böden nach ihrem chemischen Bodenzustand

Ecological grouping of soils according to their chemical soil state On the base of the solubility of carbonic acid, calcium carbonate, as well as the oxidic compounds of Al and Fe existing in soils, the following buffer ranges are defined and separated from each other by pH values in the soil solution: Carbonic acid/Carbonate buffer range (pH 6.2 to 8.6), Carbonic acid/Silicate buffer range (pH 5.0 to 6.2), Exchanger buffer range (pH 4.2 to 5.0), Aluminium buffer range (pH 2.8 to 4.2), Iron buffer range (pH 2.4 to 3.8). The buffer capacities are calculated and literature indications regarding buffer rates are compiled. The characteristical chemical soil state is demonstrated for the various buffer ranges with aid of a soil collection. With increasing soil acidification the Ca/Al mole ratio in fine roots decreases from values > 1 to values around 0.3; this is taken as evidence for increasing disposition for Al-toxicity. It is suggested to attach soil horizons to buffer ranges on the base of pH(H₂O) measurements made on field fresh samples. The measurement of pH in salt solution is taken as measure for the amplitude of the chemical soil state in case of H-ion or salt stress.     

Sensitive determination of phenolic acids in extra-virgin olive oil by capillary zone electrophoresis

A sensitive, rapid, efficient, and reliable method for the separation and determination of phenolic acids by capillary zone electrophoresis has been carried out. A detailed method optimization was carried out to separate 14 different compounds by studying parameters such as pH, type and concentration of buffer, applied voltage, and injection time. The separation was performed within 16 min, using a 25 mM sodium borate buffer (pH 9.6) at 25 kV with 8 s of hydrodynamic injection. With this method and using a liquid-liquid extraction system, with recovery values around 95%, it has been possible to detect small quantities of phenolic acids in olive oil samples. This is apparently the first paper showing the quantification of this specific family of phenolic compounds in virgin olive oil samples.     

Contributions of separate reactions to the acid–base buffering of soils in brook floodplains (Central Forest State Reserve)

The acid–base buffering of gleyic gray-humus soils developed in brook floodplains and undisturbed southern-taiga landscapes has been characterized by the continuous potentiometric titration of soil water suspensions. During the interaction with an acid, the major amount of protons (>80%) is consumed for the displacement of exchangeable bases and the dissolution of Ca oxalates. In the O and AY horizons, Mn compounds make the major contribution (2–15%) to the acid buffering. The buffer reactions with the participation of Al compounds make up from 0.5 to 1–2% of the total buffering capacity, and the protonation of the surface OH groups of kaolinite consumes 2–3% of the total buffering capacity. The deprotonation of OH groups on the surface of Fe hydroxides (9–43%), the deprotonation of OH groups on the surface of illite crystals (3–19%), and the dissolution of unidentified aluminosilicates (9–14%) are the most significant buffer reactions whose contributions have been quantified during the interaction with a base. The contribution of the deprotonation of OH groups on the surface of kaolinite particles is lower (1–5%) because of the small specific surface area of this mineral, and that of the dissolution of Fe compounds is insignificant. In the AY horizon, the acid and base buffering of soil in the rhizosphere is higher than beyond the rhizosphere because of the higher contents of organic matter and nonsilicate Fe and Al compounds.     

Aqueous photolysis of niclosamide

The photodegradation of [(14)C]niclosamide was studied in sterile, pH 5, 7, and 9 buffered aqueous solutions under artificial sunlight at 25.0 +/- 1.0 degrees C. Photolysis in pH 5 buffer is 4.3 times faster than in pH 9 buffer and 1.5 times faster than in pH 7 buffer. In the dark controls, niclosamide degraded only in the pH 5 buffer. After 360 h of continuous irradiation in pH 9 buffer, the chromatographic pattern of the degradates was the same regardless of which ring contained the radiolabel. An HPLC method was developed that confirmed these degradates to be carbon dioxide and two- and four-carbon aliphatic acids formed by cleavage of both aromatic rings. Carbon dioxide was the major degradate, comprising approximately 40% of the initial radioactivity in the 360 h samples from both labels. The other degradates formed were oxalic acid, maleic acid, glyoxylic acid, and glyoxal. In addition, in the chloronitroaniline-labeled irradiated test solution, 2-chloro-4-nitroaniline was observed and identified after 48 h of irradiation but was not detected thereafter. No other aromatic compounds were isolated or observed in either labeled test system.     

Determination of cobalamin in nutritive supplements and chlorella foods by capillary electrophoresis-inductively coupled plasma mass spectrometry

A capillary electrophoresis-inductively coupled plasma mass spectrometric (CE-ICP-MS) method for the determination of cobalamin is described. Samples of cobalt-containing compounds were subjected to electrophoretic separation before injection into the microconcentric nebulizer (CEI-100) of ICP-MS. The Co-containing compounds studied include cyanocobalamin (CN-Cbl, vitamin B12), hydroxocobalamin (OH-Cbl), and Co(II). The species studied were well separated using a 70 cm lengthx75 microm i.d. fused silica capillary with the applied voltage set at +20 kV. A 25 mM Tris buffer (pH 9.0) containing 15 mM sodium dodecyl sulfate (SDS) was used as the electrophoretic buffer. The CE-ICP-MS detection limits were 0.3, 0.2, and 1.7 ng of Co mL(-1) for CN-Cbl, OH-Cbl, and Co(II), respectively. The concentrations of cobalamin compounds were determined in selected nutritive supplements and chlorella samples. A microwave-assisted extraction method was used for the extraction of these compounds. Over 92% of the total cobalt species was extracted using a 5% v/v HNO3 solution in a focused microwave field within a period of 10 min; spike recovery was in the range of 94-105% for various species. The major cobalt species in nutritive supplements and chlorella samples was cyanocobalamin.     

Simultaneous quantification of eight biogenic amine compounds in tuna by matrix solid-phase dispersion followed by HPLC-orbitrap mass spectrometry

A method for the extraction of agmatine, cadaverine, histamine, phenyethylamine, putrescine, tryptamine, tyramine, and urocanic acid from canned tuna and frozen tuna loin matrices by matrix solid-phase dispersion, followed by separation and quantification of these compounds by ultrahigh-performance hydrophilic interaction chromatography (UHPLC-HILIC) with orbitrap mass spectrometric detection, is described. Tuna samples are dispersed in a CN-silica sorbent and eluted with a mixture of aqueous ammonium formate buffer and acetonitrile. Separation and detection are carried out on an Agilent 1200 high-performance liquid chromatograph coupled to a Thermo Exactive orbitrap mass spectrometer, and metformin is used as the internal standard. Spike recoveries are determined across a range of 20-100 ppm for each compound, and the method is validated with respect to linearity, reproducibility, accuracy, and limits of quantitation and detection. The method is demonstrated to be suitable for use in quantifying these target compounds in the studied matrices.     

Design of riparian buffer strips affects soil quality parameters

Vegetated buffer strips alongside watercourses are commonly used to counteract diffuse pollution from agricultural activities. If properly designed, they can provide multiple environmental benefits by increasing wildlife habitats and biodiversity. Little attention has been paid to the effects of buffer strips on soil quality. This study was conducted to determine the impact of different buffer designs on soil biochemical parameters and to define relevant quality parameters for soil monitoring. We compared four buffer arrangements: 3 m wide grass buffer; 3 m grass with one tree row; 6 m grass with one tree row; 6 m grass with two tree rows; plus two controls: an adjacent maize crop field and a plot without buffer. Buffers were established 13 years ago at the Padua University Experimental Farm in the Po Valley, north-east Italy. Studied parameters included soil organic matter composition and soil microbial and enzymatic assays. As expected, control plots showed the lowest values for all the studied parameters. Among buffer designs, 3 m grass and 3 m grass with 1 tree row buffers gave the highest values. Multivariate analysis demonstrated that the increase of soil organic carbon content distinguished buffers from controls, whereas soil humic carbon quality parameters such as humic compounds apparent molecular weight, together with acetyl esterase (fluorescein test) enzyme activity, were discriminatory in separating buffer designs. These results are an important contribution to the knowledge base and can help to improve the management of these systems.     

Direct automatic determination of bitterness and total phenolic compounds in virgin olive oil using a pH-based flow-injection analysis system

Flavor and taste are sensorial attributes of virgin olive oil (VOO) highly appreciated by consumers. Among the organoleptic properties of VOO, bitterness is related to the natural phenolic compounds present in the oil. Sensorial analysis is the official method to evaluate VOO flavor and bitterness, which requires highly specialized experts. Alternatively, methods based on physicochemical determinations could be useful for the industry. The present work presents a flow-injection analysis system for the direct automatic determination of bitterness and total phenolic compounds in VOO without prior isolation, based on the spectral shift undergone by phenolic compounds upon pH variation. This system enables a complete automation of the process, including dilution of the sample and its sequential injection into buffer solutions of acidic and alkaline pH. The variation of the absorbance at 274 nm showed a high correlation with bitterness and the total phenolic content of VOO, due to the close relationship between these two parameters. Thus, the proposed method determines the bitterness and phenolic compounds, with results similar to those from reference methods (relative errors ranging from 1% to 8% for bitterness and from 2% and 7% for phenolic compounds). The precision evaluated at two levels of both parameters ranged between 0.6% and 1.5% for bitterness and between 0.7% and 2.6% for phenolic compounds.     

The effect of high pressure-high temperature processing conditions on acrylamide formation and other Maillard reaction compounds

The effect of high pressure-high temperature (HPHT) processing on the formation of acrylamide and other Maillard-type reaction compounds was investigated in order to elucidate the impact of HPHT conditions on the different stages of the Maillard reaction. This study was performed in equimolar asparagine-glucose model systems that were treated at various HP/HT conditions (100-115 °C, 400-700 MPa, 0-60 min), and, for comparison, the model system was also heat-treated at ambient pressure. On the treated samples, the concentration of acrylamide, reactants, hydroxymethylfurfural, organic acids, and melanoidins was determined and the pH prior to and after treatment was measured. Based on the measured responses, the retarding effect of high pressure on the overall Maillard reaction was demonstrated; no or little differences were observed between 400 and 700 MPa. The study was conducted in two types of buffer, i.e. phosphate and MES buffer. In case of acrylamide, aspartic acid and browning, a higher concentration was generated in the MES buffer system, but these differences with the phosphate buffer system could be ascribed to pH changes resulting from the application of combined high pressure and high temperature. Based on the results, acrylamide formation is not expected to pose a major hazard to HPHT-treated products.     

Extraction and properties of phosphodiesterase from a forest soil

Phosphodiesterase together with brown-coloured compounds was extracted from a forest soil using 0.1 M phosphate buffer (pH 7). Use of KCl and EDTA with the buffer facilitated phosphodiesterase extraction. Distilled water extracted little enzyme activity. A curvilinear relationship such as the Langmuir type was found between solution volume and phosphodiesterase activity of the extract. The results implied that the phosphodiesterase extracted was extracellular and was adsorbed on the surface of soil particles by ionic bonding. Brown-coloured compounds in the extract were removed by precipitation with protamine sulfate. The phosphodiesterase activity of the extract treated with protamine sulfate was lost on keeping at 80°C for 10 min and was optimal at pH 5.2–6.0. The extract hydrolyzed either the 3'- or the 5'-phosphodiester bond of deoxythymidine p-nitrophenyl phosphate.     

Determination of gibberellic acid in fermentation broth and commercial products by micellar electrokinetic chromatography

Micellar electrokinetic chromatography (MEKC) was developed as a method for quantitative determination of gibberellic acid (GA3) in fermentation broth and commercial products, using 25 mM disodium tetraborate as a buffer at pH 9.2 and 100 mM sodium dodecyl sulfate as a micellar phase. The baseline resolution (Rs of GA3 from other compounds in fermentation broth was achieved with Rs > 2.5. The addition of methanol or acetonitrile in the MEKC buffer did not give a better resolution. Advantages of this MEKC method include high accuracy and precision and no sample preparation except for dilution and filtration.     

Spatial and temporal variability in precipitation chemistry in the urban area of Greater Manchester

To investigate the spatial and temporal variability of acid deposition in the urban environment a small-scale intensive network of bulk collectors has been deployed around Greater Manchester, UK. This network has been in operation since 1986. The concentrations and deposition rates of non-marine (nm) sulphate, nitrate, ammonium, calcium and hydrogen are reported for 1994. Acidity was generally lower in the city centre of Manchester where calcium concentrations were highest. Calcium compounds in the urban atmosphere effectively buffer the precipitation acidity.     

Determination of taurine in infant formulas using ultrafiltration and cation-exchange chromatography

A fast and simple method for determination of taurine in infant formulas has been developed. The sample preparation uses disposable ultrafiltration cartridges to remove protein and clarify the sample. Hydrolysis is avoided, simplifying the procedure and increasing efficiency. One mL sample is centrifuged in a cartridge for 45 min. The filtrate is diluted with pH 2.2 citrate buffer and injected into a high performance amino acid analyzer. A cation-exchange column (sodium phase) is used with a single buffer eluant and an isocratic chromatographic program. Colorimetric detection is performed following post-column ninhydrin reaction. Chromatographic resolution from other ninhydrin-positive compounds is excellent. Average recoveries for 3 levels of spike for various products were 100-102%. Precision is 1-3% RSD, depending on product. Linearity, specificity, and ruggedness are excellent. The method is applicable to quality control testing of milk-based, soy-based, and prehydrolyzed protein-based infant formulas in the ready-to-use, concentrate, and powder forms. A variety of commercially available infant formulas from different manufacturers were analyzed and all were found to contain taurine levels comparable to human milk. Some human milk and cow's milk samples were also analyzed and results compare well with literature values.     

Identification and quantitation of key aroma compounds formed in Maillard-type reactions of fructose with cysteamine or isothiaproline (1,3-thiazolidine-2-carboxylic acid)

Fructose was reacted in the presence of either cysteamine (model A) or isothiaproline (model B) in aqueous buffer at 145 degrees C and pH 7.0. Application of an aroma extract dilution analysis on the bulk of the volatile compounds formed in model A revealed 5-acetyl-3,4-dihydro-2H-1,4-thiazine (19), N-(2-mercaptoethyl)-1,3-thiazolidine (16), 4-hydroxy-2,5-dimethyl-3(2H)-furanone (15), and 2-acetyl-2-thiazoline (11) as the key aroma compounds among the 10 odorants detected. A similar set of aroma compounds was formed when isothiaproline was reacted (model B), but the flavor dilution factors were generally lower. Substitution of the buffer by silica gel/water (9 + 1 w/w) in both models and application of 150 degrees C for 10 min also gave the same key odorants from both thio compounds; however, under these conditions isothiaproline was the better precursor of, in particular, 19 and 11. Quantitative measurements performed by means of stable isotope dilution assays revealed a significant effect of the pH on odorant formation. For example, in model A, formation of 19 as well as of 11 was suppressed at pH values <5.0. A clear maximum was, however, found for 19 at pH 7.0 (approximately 1 mol % yield), whereas 11 increased with increasing pH from 7.0 to 9.0.     

Pre-lysis washing improves DNA extraction from a forest soil

A pre-lysis buffer washing procedure was introduced to DNA extraction from a forest soil with high organic matter and iron oxide contents. Sodium phosphate of 0.1 M (pH 7.5) was used as a buffer to wash soil samples when subsequent lysis buffer was phosphate, and 20 mM EDTA (pH 7.5) was used when subsequent lysis buffer included EDTA. Initial experiments were not successful because the DNA extracts could not be amplified by polymerase chain reaction (PCR). The consideration of introducing a pre-lysis washing procedure was based on the idea that the washing should promote soil dispersion and homogeneity, decrease DNA adsorption by soil components (e.g. iron oxides), and remove covalent cations and those easily-dissolving organic compounds from the soil samples. Results revealed that humic substance content decreased by 31%, but DNA yield increased by 24% in the DNA extracts of the pre-lysis washing procedures, compared to the non-washing procedures. DNA extracted by the pre-washing procedure needed less purification for subsequent 18S and 16S rDNA PCR amplifications. It was recommended that the pre-lysis buffer washing should be used for DNA extraction from those difficult environmental samples, such as the forest soil with high contents of organic matter and iron oxides.     

Designing the buffer zone of a nature reserve: a case study in Yancheng Biosphere Reserve, China

The problems existing in design of buffer zones are analyzed, and a procedure for designing the buffer zone of reserves is proposed. The Analytic Hierarchy Process (AHP) is applied to design the width of buffer zone. The different importance of influences in different sections around the reserve leads to different widths of buffer zone being designated around the reserve. The method is illustrated by a case study, designing the buffer zone for the Yancheng Biosphere Reserve, China.     

A new method for determining ferrous iron in paddy soils

Introduction

To make clear the chemical behavior of free iron compounds in paddy soils, it is necessary to find an accurate and rapid method for determining ferrous iron in waterlogged paddy soils. Several methods^1,2,3) have been proposed for this purpose, most of which use dilute acids, such as sulfuric and hydrochloric acid, as extracting reagents. According to the writers' experience, however, these methods seem to be inadequate. The reason is that the acid solutions extract not only ferrous iron, but also ferric iron and reducing substances from soils, and the latter two react immediately in the extract to produce ferrous iron, thus we obtain larger value for ferrous iron than the one actually existing in soils. The writers have found that acetate buffer of pH 2.8 is a very suitable extractant for ferrous iron, and they have been able to establish a new method for the determination of ferrous iron in soils using this buffer. The experimental details will be given in this paper.     

Oxidative deamination of benzylamine and lysine residue in bovine serum albumin by green tea, black tea, and coffee

Oxidative deamination by various polyphenolic compounds is presumed to be due to the oxidative conversion of polyphenols to the corresponding quinones through autoxidation. Here we examined the oxidative deamination by the polyphenol-rich beverages green tea, black tea, and coffee at a physiological pH and temperature. Green tea, black tea, and coffee extracts oxidatively deaminated benzylamine and the lysine residues of bovine serum albumin to benzaldehyde and alpha-aminoadipic delta-semialdehyde residues, respectively, in sodium phosphate buffer (pH 7.4) at 37 degrees C in both the presence and absence of Cu2+, indicating the occurrence of an amine (lysyl) oxidase-like reaction. We also examined the effects of pH and metal ions on the reaction. The possible biological effects of drinking polyphenol-rich beverages on human are also discussed.     

河溪缓冲带的生态功能及其管理原则

河溪缓冲带位于陆地生态系统与水生生态系统的之间,是河溪生态系统的重要组成部分,具有多种生态功能。着重介绍了河溪缓冲带的物种天堂、养分来源、稳固河岸、改善水质、景观价值、缓解影响这6种功能。由于现在交通和建设用地的不断增加,河溪缓冲带的人为破坏现象严重,亟需得到科学的管理和恢复。提出了3条缓冲带科学管理的基本原则,为不同地域、不同等级的河溪缓冲带的建设和恢复提供了指导。并以北京市海淀区内的南沙河河溪缓冲带的情况为例,加以印证说明。     

Riparian forest buffer system research at the coastal plain experiment station,Tifton, GA

Recent attention has focused on riparian forest buffer systems for filtering sediment, nutrients, and pesticides entering from upslope agricultural fields. Studies in a variety of physiographic areas have shown that concentrations of sediment and agrichemicals are reduced after passage through a riparian forest. The mechanisms involved are both physical and biological, including deposition, uptake by vegetation, and loss by microbiological processes such as denitrification. Current research by USDA-ARS and University of Georgia scientists at Tifton, GA is focusing on managing riparian forest buffer systems to alleviate agricultural impacts on the environment. The underlying concept for this research is that agricultural impact on streams is best protected by a riparian forest buffer system consisting of three zones. In consecutive upslope order from the stream these zones are (1) a narrow band of permanent trees (5–10 m wide) immediately adjacent to the stream channel which provides streambank stabilization, organic debris input to streams, and shading of streams, (2) a forest management zone where maximum biomass production is stressed and frees can be harvested, and (3) a grass buffer strip up to 10 m wide to provide control of coarse sediment and to spread overland flow. Several ongoing projects at Tifton, GA are focusing on using riparian forest buffer systems as filters. A forest management project is testing the effects of different management practices on surface and ground water quality. This project includes three different forest management practices: mature forest, selectively thinned forest, and clearcut. In a different study a natural wetland is being restored by planting frees. The effectiveness of this wetland on filtering nutrients from dairy wastes which are being applied upslope is being evaluated. At this same site, a pesticide study is being conducted on the side opposite to where dairy wastes are applied. An overland flow-riparian buffer system using swine lagoon waste is evaluating the effectiveness of different vegetative treatments and lengths of buffer zones on filtering of nutrients. In this study three vegetative treatments are compared: (1) 10 m grass buffer and 20 m riparian forest, (2) 20 m grass buffer and 10 m riparian forest, (3) 10 m grass buffer and 20 m of the recommended wetland species maidencane. Waste is applied at the upper end of each plot at either a high or low rate, and then allowed to flow downslope. The three zone riparian forest buffer system is being used for the Riparian Ecosystem Management Model (REMM). This model, which is currently under development at Tifton, GA, is a computer simulation model designed to reduce soil and water degradation by aiding farmers and land use managers in decision making regarding how best to utilize their riparian buffer system. Both information currently being collected in field studies and development of the REMM are innovative farm-level and forestry technologies to protect soil and water resources.