HPLC with on-line ICP-MS was used for the determination of V(IV) and V(V) in natural mineral water. Cationic and anionic tetravalent and pentavalent vanadium species were converted into V-EDTA complexes, i.e. [VO(EDTA)] 2À and [VO 2 (EDTA)] 3À , which could be effectively separated on a short anion exchange column in <6 min. Pre-column EDTA complexation also prevented species interconversion as a result of loss of CO 2 from samples and their exposure to atmospheric oxygen. A low-salt mobile phase (4 mM carbonate buffer and 5 mM EDTA-Na 2 ) compatible with ICP-MS detection was used in chromatographic separations. The method was tested on real samples spanning one order of magnitude of V concentrations and encompassing a wide range of potential interfering ions and total dissolved solids, providing accurate and reproducible results. Mass balance budgets gave a mean value of 100% (range 96-107%). Recoveries from spiking experiments were in the range 98-103%. Precision as average intra-day repeatability was 1.2% and 0.9% for V(IV) and V(V), respectively. Average inter-day repeatability was 5.5% and 1.4% for V(IV) and V(V), respectively. Limits of detections were 0.16 mg L À1 for V(IV) and 0.025 mg L À1 for V(V). The interference arising by 35 Cl 16 O was resolved chromatographically. V(V) was found to largely predominate in PET-bottled mineral water samples. Species distribution was consistent with theoretical predictions based on thermodynamic equilibria of vanadium in water. Overall, a rapid, sensitive, on-line method is provided which can be readily employed for monitoring purposes. 2À, with polynuclear species, e.g., decavanadates H x V 10 O 28 (6 À x) existing only above a critical concentration (''mononuclear wall''
Centred around the topic of dialogue, the philosophical position which Guido Calogero (1904-1986) came to hold at the beginning of the 1950s, and developed in his subsequent studies, establishes a complex relationship with the philosophical research from the years before, interested in the historical origins of the logical and gnoseological problems in ancient thought and their necessary dissolution in contemporary idealism. This work highlights how these bonds condition the formulation of the dialogic principle, despite the philosopher's intention to assert its speculative autonomy; but it also shows, at the same time, how this renewed ethical criterion enriches Calogero's position, opening it to developments that contemporary reflection can acquire and investigate further.
An increasing interest for the theme of recognition and of intersubjective relationships has been registered in the last decades. In this frame a new interest for Hegel’s theory of recognition has also been developed. This new interest focuses mostly only on the figure of struggle for recognition in the Phenomenology of Spirit. Nevertheless, Hegel’s theory of recognition has a much wider structure: it is not limited to this conflictual moment, but also connects to the themes of forgiveness and of love. That’s why it also offers the premise for a discussion of the theme of hospitality. The connection between recognition and hospitality has been emphasized by Paul Ricoeur in his last writings, dedicated to the theme of translation and to the different courses of recognition.
According to the interpretation of Hegel, Egyptian religious buildings, and among them especially the temples, represent the beginning of the history of architecture, and so the beginning of the entire history of art.The Egyptian religious architecture has a symbolic character, because its configuration tries to represent the spiritual content without being fully adequate to it. So the Egyptian temple alludes to the divine through its entire structure, but does not have a proper internal space, dedicated to the worship of the image of God.On this point, contemporary Egyptology corrected Hegel’s view, because broadly speaking the Egyptian temple had an interior where the image of the deity was safeguarded. However, Hegel’s thesis paradoxically remains suitable for a particular case of the Egyptian experience that he could not know at that time: in the monotheistic religion of Amarna, the temple of the sun-god Aton has no images and does not have a center, because the Divine is present everywhere, like the sunlight that illuminates equally all over the temple.
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