The simple PVC-based membrane containing N,N',N'',N'''-tetrakis(2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane (tpmc) as an ionophore and dibutyl phthalate as a plasticizer, directly coated on a glassy carbon electrode was examined as a new sensor for Cu 2þ ions. The potential response was linear within the concentration range of 1.0 Â 10 À1 -1.0 Â 10 À6 M with a Nernstian slope of 28.8 mV/decade and detection limit of 7.0 Â 10 À7 M. The electrode was used in aqueous solutions over a wide pH range (1.3 -6). The sensor exhibited excellent selectivity for Cu 2þ ion over a number of cations and was successfully used in its determination in real samples.
Five types of red wine produced from the grape varieties from the Metohia region (vintage 2014) were characterized on the basis of their chromatic properties. The properties of bottled wines: Merlot, Vranac, Prokupac, Cabernet and Game were analyzed. Chromatic characteristics of these wines were observed four times during the year-spectrophotometer measurements were performed on wines aged 0, 4, 8 and 12 months. Intensity, hue and brilliance of color of these wines were determined (by the usual method of Glories). The amount of coloring matter was determined by the usual method of Durmishidze and the percentage of polymeric anthocyanins was calculated as well. Wine ageing decreased the color intensity while the color hue value increased. It was also found that contribution of wine color red pigment decreased with wine ageing, while the percentage of yellow pigment in wine increased. The total amount of colored substances in wines studied decreased with wine ageing, while the percentage of polymeric pigments in wine increased. This study presents the methodology for analyses of the chromatic characteristics, and explains the origin influence of wine on these properties. On the basis of these correlations the quality of red wine can be established.
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