Premium
Voltammetric Monitoring and Speciation of Copper Ions in Italian “Grappa” with Platinum Microelectrodes
Author(s) -
Baldo M. Antonietta,
Daniele Salvatore
Publication year - 2006
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.200503459
Subject(s) - copper , linear sweep voltammetry , chemistry , platinum , anodic stripping voltammetry , ethanol , ion , analytical chemistry (journal) , linear range , stripping (fiber) , detection limit , inorganic chemistry , nuclear chemistry , electrochemistry , electrode , chromatography , materials science , cyclic voltammetry , catalysis , organic chemistry , composite material
A linear sweep voltammetric (LSV) investigation and the anodic stripping voltammetric (ASV) detection of copper ions in ethanol‐water mixtures and grappa samples are reported. The measurements are carried out by using platinum microdisk electrodes. Ethanol‐water mixtures with ethanol content in the range 40–100 vol%, commercially available and raw grappa samples having ethanol content in the above range are examined. From LSV measurements of copper (II) ions added to the samples, the formation of intermediate copper (I) soluble species, which are stabilized mainly by the naturally occurring organic compounds present in the real samples, is observed. The analysis of LSV and ASV current responses against added Cu 2+ ions provides linear trends over the concentration range 5×10 −5 −5×10 −3 M and 5×10 −7 −5×10 −5 M, respectively. The sensitivity depends on the ethanol content in the mixture and, as expected, it is the higher the lower the viscosity of the medium. In particular, it varies from 1.54 to 3.53 nA mM −1 and from 0.114 to 0.263 nA μM −1 for LSV and ASV measurements, respectively, upon changing the ethanol content from 40 to 100 vol%. In the same range of ethanol content, detection limits obtained by ASV vary from 0.27 to 0.15 μM, respectively. Labile or total copper contents in the grappa samples are determined by ASV measurements performed in the untreated matrices or in the samples acidified with 0.1 M HClO 4 , respectively. Finally, acidification of the samples with different amounts of HClO 4 allows also some speciation investigations to be performed.