Extraktionsverfahren zur simultanen Bestimmung von Natrium, Kalium, Calcium, Magnesium, Eisen, Kupfer, Zink und Mangan in organischem Material mit Hilfe der Atomabsorptionsspektrophotometrie

Zusammenfassung Das beschriebene Extraktionsverfahren ermöglicht die Bestimmung von Natrium, Kalium, Calcium, Magnesium, Eisen, Kupfer, Zink und Mangan in organischem Material aus einem Aufschluß. Das Extraktionsverfahren liefert im Vergleichmit konventionellen Methoden [1, 2, 4] übereinstimmende Werte für die Elemente Natrium, Kalium, Calcium, Magnesium, Eisen und Mangan. Für die quantitative Bestimmung von Kupfer und Zink ist die Extraktionsmethode der trockenen Veraschung bei 450° C [1, 4] überlegen. Daruber hinaus ist die Extraktionsmethode der trockenen Veraschung vorzuziehen, da Probenmenge, Zeitbedarf und Kosten bei der Verwendung der beschriebenen Methode wesentlich gesenkt werden können.

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Extraction method for the simultaneous determination of sodium, potassium, calcium, magnesium, iron, copper, zinc and manganese in organic material using atomic absorption spectrophotometry

Summary Determination of sodium, potassium, calcium, magnesium, iron, copper, zinc, and manganese in organic material is possible with one digestion using the described extraction method. Data for sodium. potassium, calcium, magnesium, iron, and manganese agree well with those obtained by conventional methods [1, 2, 4]. For quantitative determination of copper and zink the extraction method is superior to dry ashing at 450° C [1, 4]. In general the extraction method ist preferable to dry assing, because the amount of sample, time and costs can be reduced essentially using the described method.

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Die Untersuchungen wurden mit Mitteln des Ministeriums für Wissenschaft und Forschung des Landes Nordrhein-Westfalen durchgefuhrt     

Nanosilver in consumer products and human health: more information required!

Commenting on "120 Years of Nanosilver History: Implications for Policy Makers" (Environ. Sci. Technol.2011, 45, 1177-1183). The title of the article seduces readers to the impression that we can look back at more than a century of safe use of nanosilver. In this context, colloidal silver and nanosilver have been sometimes used as synonyms. Historically, the term "colloidal silver" refers to dispersed silver particles encompassing a size range of 10-1000 nm. Following scientific definitions, "colloid" stands for freely dispersed particles in a fluid (heterogenic) phase irrespective of its size distribution, while the term "nanosilver" is used for categorization by size. Of course, just the labeling as such neither necessarily implies new hazard properties nor any specific risks; however, uncertainties and data gaps at many levels call for careful consideration and usually should take effect as alert signal for regulatory toxicologists all over the world. Within the frame of this short commentary, we would like to focus on some unclarified issues related to consumer products.     

Nachweis von Diethylenglycol in Wein Detection of Diethylenglycol in Wine

European Food Research and Technology - Der Nachweis von Diethylenglycol durch Dünnschichtchromatograpllie nach Anreicherung mittels Extrelut-Fertigsäule wird beschrieben. Die...     

Managing risks in the Indonesian seaweed supply chain

Seaweed supply chains in Indonesia, especially carrageenan and agar products, are subject to risks arising both inside the participating companies and in their external networks. Uncertainties in yield, quality, price, and infrastructure in one part of the supply chain can affect the whole chain. To ensure a sustainable seaweed industry, an appropriate supply chain risk management (SCRM) is needed. There are four critical steps in SCRM: identifying seaweed supply chains, identifying and categorizing risks, assessing risks, and mitigating risks. To identify seaweed supply chains, we conducted field research, in-depth interviews, and literature studies. The field survey was conducted in the Provinces of South Sulawesi, West Java, East Java, Banten, and West Nusa Tenggara. The seaweed supply chains were modeled by the software Umberto to get a better understanding of material and energy flows between the key members. To identify and categorize the risks, we started with the risks mentioned in the existing literature works, and then applied the Delphi method to analyze the potential risk sources, their causes, and their impacts. To assess risks, we used a semiquantitative approach through the face-to-face interviews to generate a risk map showing the likelihood, and impact of adverse events. Afterward, the risk intensity was categorized based on the value of the responses and classified into five categories: negligible, marginal, critical, most critical, and catastrophic risks. The mitigation strategies considered sustainability (environment, economy, and social) and risks criteria. Multi-criteria decision analysis was used to evaluate these strategies.     

Intergranular corrosion of iron-phosphorus alloys in nitrate solutions

The corrosion of Fe-P alloys with 0.003–2.5 wt.%P has been studied in hot nitrate solutions. The current-potential curves show an extended active range and increased corrosion currents for high phosphorus alloys. The alloy with 2.5P does not passivate at all. The other alloys have been tested for intergranular corrosion in the passive range at 1,000 mV(SHE). The intergranular attack increases with increasing phosphorus content and can be correlated to its grain boundary concentration. The grain boundary concentrations had been established by equilibrium segregation at temperatures between 400 and 80°C and were determined by Auger electron spectroscopy (AES). The presence of phosphorus in solid solution and segregated to the grain boundaries prevents the formation of a passive layer on iron, if its local concentration is higher than ca. 2–3 at.%.     

Ganzheitliche Betrachtung bei Analyse,Planung und Ausführung von Sanierungen - Risikomanagement im Altbergbau

Examination and rehabilitation of mining legacies often result initially in separate risk management systems for surface openings and near-surface mining activities. On the one hand this can be explained by more or less spectacular past loss events around abandoned surface openings and on the other hand by the gradual change of approach to and perception of the issue of abandoned near-surface mines in the last centuries respectively, that has taken place lately. Initially, the focus used to rest on the entrances as they present a high but spatially limited risk potential and, being technical underground structures that break through the surface, they are also easier to detect and prioritise than near-surface mining or other mine workings. Against this background, this risk assessment, prioritisation and rehabilitation limited purely to the surface openings does make sense for large deep mining shafts. For smaller surface openings like, for example sloping shafts which were mostly driven in the seam, however, it is imperative to evaluate the risk in dependence on the associated seam as well as the near-surface mining operations which took place therein. For this reason, with respect to the risk management of abandoned near-surface mines, it is essential to take a holistic approach to analysis and evaluation but above all concerning implementation planning and rehabilitation of mine workings and affected areas respectively. On the one hand it comprises all facts to be collected beforehand and the possibly resulting reciprocal effects, however, on the other hand, influences resulting from exploratory or rehabilitation measures themselves are also of importance. Any intervention in the underground has the potential to at least upset the temporary balance and can for this reason actively change the risk potential.     

Oxidation/reduction Reactions of molybdate ions in sodium sulfate at 1200 K

Cyclic voltammetric studies have been used to elucidate the electrochemical and coupled chemical reactions of solute molybdate ions on sodium sulfate at 1200 K in different melt basicities fixed by SO₂-O₂ atmospheres. The reaction mechanism was determined by use of the Nicholson and Shain diagnostic criteria in combination with the phase stability diagram. Within the regime of sodium sulfate stability, three reduction reactions occur. In a highly acidic melt, the reduction of molybdate ions (Mo in + 6 oxidation state) to Mo as + 4 is coupled to an irreversible chemical reaction whereby molybdenum dioxide precipitates. Molybdenum in oxidation state + 4 is reduced to Mo-(+2)-species which are immediately reoxidized to Mo-(+4)-species by an oxidizing agent in the melt, a so-called catalytic reaction. The reduction of Mo-(+2)-species to molybdenum follows in a very narrow potential range close to the previous reaction and has the same catalytic reaction mechanism. The reduction reactions are reversible. The reverse oxidation of molybdenum to the molybdate ion proceeds in three electron transfer steps.