Ein Beitrag zur Bestimmung von Anilin/Phenol in Wasser/Abwasser mittels UV-Derivativspektroskopie. Teil 1: Das analytische Grundverfahren

Ultraviolet derivative spectroscopy was used as an analytical tool for the direct and simultaneous determination of aniline and phenol in water. It is shown that the diA/dλi values are proportional to aniline (i = 2, 4) and phenol (i = 2, 4 and 5) concentrations at 205.3 or 271.6 … 282.8 nm. The performance characteristics are discussed in detail. Thus the best precision resulted in both aniline and phenol for the second derivatives. The accuracy of the methods applied is independent on the derivative order and concentration levels within the dynamic range of 1 to 10 mg · 1^?1 aniline or phenol respectively.     

Single-Column Model Intercomparison for a Stably Stratified Atmospheric Boundary Layer

The parameterization of the stably stratified atmospheric boundary layer is a difficult issue, having a significant impact on medium-range weather forecasts and climate integrations. To pursue this further, a moderately stratified Arctic case is simulated by nineteen single-column turbulence schemes. Statistics from a large-eddy simulation intercomparison made for the same case by eleven different models are used as a guiding reference. The single-column parameterizations include research and operational schemes from major forecast and climate research centres. Results from first-order schemes, a large number of turbulence kinetic energy closures, and other models were used. There is a large spread in the results; in general, the operational schemes mix over a deeper layer than the research schemes, and the turbulence kinetic energy and other higher-order closures give results closer to the statistics obtained from the large-eddy simulations. The sensitivities of the schemes to the parameters of their turbulence closures are partially explored.     

Determination of Polar Organic Pollutants in Aqueous Samples of Former Ammunition Sites in Lower Saxony by Means of HPLC/Photodiode Array Detection (HPLC/PDA) and Proton Nuclear Magnetic Resonance Spectroscopy ( 1H-NMR)

Leachate, ground-, and surface water from former ammunition sites and areas which are known to be contaminated by nitroaromatic compounds in Lower Saxony (Germany) were investigated in order to identify and quantify acidic nitroaromatic compounds (e.g., nitrobenzoic acids, aminonitrobenzoic acids, nitrophenols, and nitrocresols). Acidic and neutral nitroaromatic compounds were enriched by solid-phase extraction (SPE) on a polystyrenedivinylbenzene copolymer and routinely screened for acidic compounds by means of HPLC/photodiode array detection (HPLC/PDA). Qualitative and quantitative results obtained in this way were corroborated by proton nuclear magnetic resonance spectroscopy (¹H-NMR). Validation data for the quantification procedure using this technique are given. The results show that all samples contaminated with 2,4,6-trinitrotoluene (TNT) and related compounds are also contaminated by acidic nitroaromatic compounds (e.g., 2,4-dinitrobenzoic acid, 3,5-dinitrophenol, and especially with 2-amino-4,6-dinitrobenzoic acid) in the μg/L range. This current work shows that 1 H-NMR allows the quantitative determination of protoncarrying analytes in mixtures after solid-phase extraction down to the upper ng/L range after addition of an internal standard to the SPE extract. This is even possible when reference compounds are not commercially available.     

Ein Beitrag zur Bestimmung von Anilin/Phenol in Wasser/Abwasser mittels UV-Derivativspektroskopie. Teil 2. Das reale Verfahren und Untersuchungen zum Störeinfluß von Fremdstoffen

Summary: The application of the UV derivative spectroscopy method to determine aniline and phenol in spiked waste water samples was investigated. Two statistical procedures (modified t-tests) were used to evaluate constant and percentage systematic errors of the method presented. On our conditions, i.e. type of samples, the aniline determination by the 2nd and 4th derivatives was predominantly disturbed but in contrary the phenol concentrations of all samples determined by the 4th and 5th derivatives show no significant bias. The influence of substituted phenols was examined by factor experiments (Plackett-Burman-plan). Generally the higher derivative order brings the better resolving power and in part then the interference is eliminated (p-cresol, hydroquinone).     

Nitrat-Bestimmung in Oberflächengewässern als Beispiel der Anwendung der UV-Derivativspektroskopie in der Umweltanalytik

Artificial nitrate solutions and a large number of membranefiltered nitrate-containing water samples from Mecklenburgian lakes and rivers were investigated in the spectral range of 200… 260 nm with a dual beam spectrophotometer. By the formation of derivative spectra there are achieved a higher spectral resolution and the elimination of undesired disturbing effects since first- and higher-order derivatives are formed. As it is known, the direct spectrophotometric nitrate determination is influenced by organic substances and some inorganic ions of natural waters. As a result, the UV derivative spectroscopy of 2nd order is recommended as a suitable technique of nitrate analysis for surface waters with a high degree of accuracy and precision – detailed reports on investigations being given. Compared with the equivalent salicylate method, however, the expenditure of the UV derivative spectroscopy described is considerably lower.     

Ein Beitrag zur Seston-Eliminierung mit Mikrosiebfiltern

The treatment of a highly eutrophic raw water is investigated by a differentiated microscopic analysis of the seston particles in three size classes, an analysis of the assimilation pigments and of the seston solids. At an average number of particles of 10⁶/ml elimination amounts to 31… 44%. The average pigment content of 124 mg/m³ chlorophyll a plus phaeopigments is reduced by 34%, the average dry matter of 14.6 mg/l being reduced by 50%.     

Climatic changes,magnetic intensity variations and fluctuations of the eccentricity of the earth's orbit during the past 2,000,000 years and a mechanism which may be responsible for the relationship

Our investigation of deep-sea climatic and magnetic records showing that high eccentricity of the earth's orbit, low magnetic field intensity and warm climate occur together indicates the relative importance of eccentricity as perhaps the phenomenon which has most consistently modulated both climate and magnetism for at least the past 2,000,000 years. A speculative hypothesis regarding the mechanism which may be responsible for a relationship between the eccentricity of the earth's orbit, geomagnetism, and climate is suggested.