1,721,026 research outputs found
Tell Tuqan and the Matkh Basin in a Regional Perspective : Thoughts and Questions Raised by the International Conference
No full textStudio multivariato delle interferenze nella spettroscopia atomica mediante empirical modelling ed experimental design
No full textThe determination of heavy metals in the Ligurian Sea. II. The geographical and vertical distribution of Cd, Cu, and Ni.
No full textina kibrat erbetti. Studi di Archeologia orientale dedicati a Paolo Matthiae
No full textIl volume, presentato a Paolo Matthiae in occasione del suo 65° compleanno, raccoglie 25 contributi di studiosi non solo italiani, che rappresentano approcci diversi all'archeologia e alla storia dell'arte del Vicino oriente antic
Determination of metal ions concentration and speciation in seawater by titration with an iminodiacetic resin.
No full textAchelating resin containing iminodiacetic groups, Chelex 100 which is often employed for sorbing metal ions from complex
matrices, was used for separating and preconcentrating heavy metal ions from seawater samples. The resin titration method
was applied for determining the total concentration. The experimental procedure consists of measuring the concentration of
the metal sorbed on Chelex 100 from solutions with different ratios volume of aqueous phase/amount of resin. The total metal
ion concentration is obtained from the experimental data by a model for the sorption on the resin, the parameters of which
are obtained by a non-linear regression procedure. In this way not only the total metal ion concentration can be determined,
but also the side reaction coefficient M.I/, if the sorption equilibria of the considered metal ion on the resin are exactly
known, as is the case of Chelex 100 considered here. The resin titration with Chelex 100 was utilized for determining the total
metal ion concentration in certified seawater samples and real samples from the Ligurian Sea. It allowed the simultaneous
determination of the total concentration of manganese(II), cadmium(II), nickel(II) and copper(II), in acceptable agreement
with the certified values. Moreover, the side reaction coefficients of some complex species could be evaluated. They were
very high, and strongly dependent on the acidity of the sample solution. For instance, values varying from 109 to 1011 were
obtained for copper (II) in the different samples considered, at pH around 7. Chelex 100 is such a strong sorbing substance
that it is able to compete with the stable complexes for the combination with the heavy metal ions considered here
Study of the influence of free dissolved amino acids on copper(II) adsorption/remobilization from inorganic fractions of marine sediments using a reversed-phase liquid chromatographic procedure
No full text
Comparison of the performance of RP C18 on silica and polymeric supports for the liquid chromatographic separation of metal-amino acid complexes with postcolumn derivatization
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
- …
