Influence of small alcohol concentrations on the conductimetric behaviour of a natural polyelectrolyte (laurel, laurus nobilis)

Surface acoustic wave sensing of linear alcohols using para-acylcalix[n]arenes

“…Only for para-hexanoylcalix [6]arene this is the case. para-Hexanoylcalix [8]arene does not discriminate between the molecules and para-hexanoylcalix [4]arene shows a higher frequency change for the less volatile molecule. The use of the three molecules permits a clear discrimination between the two structurally very similar analytes.…”

“…The surfaces show clear visible differences with those of parahexanoylcalix [4]arene and para-hexanoylcalix [8]arene showing relatively flat surfaces composed of cavities whereas the surface of para-hexanoylcalix [6]arene appears to be composed of microcrystallites. This structuration is reflected in the measurement of the surface roughness (RMS, root mean square surface roughness average), with values of 0.7 nm for the calix [4]arene, 28.9 nm for the calix [6]arene and 3.5 nm for the calix [8]arene. Such an increased roughness is a direct reflection of the presence of crystallites.…”

“…1 However the detection of other volatile alcohols has received far less attention. 2 Methods for detection of alcohols range from colorimetric, 3 conductimetric 4 to quartz crystal microbalance (QCM). 5 Other highly sensitive gravimetric measurements such as surface acoustic wave sensors (SAW) 6 would seem to be prime targets for expanding methods for the detection of volatile organic molecules (VOCs).…”

“…Scheme 1 para-Hexanoylcalix [4]arene (a) C6C4, para-hexanoylcalix [6]arene (b) C6C6 and para-hexanoylcalix [8]arene (c) C6C8.…”

Influence of the ligand concentration and pH on the complexation of Cu(II) by a soil fulvic acid

“…Among other, electrochemical techniques have been extensively used in this type of analysis, and anodic stripping voltammetry (ASV) could be an useful choice to obtain information for the study of complex chemical interactions, due to its very low detection limit and the small changes induced in the equilibria. Therefore, it was decided to include ASV in a project that has been in progress in our Departments, to obtain data that can complete information about humic and humic-like substances and their interaction with metal ions obtained by other techniques [5][6][7][8][9][10][11][12][13][14]. In the present paper, the results of a voltammetric study about the influence of the concentration of a soil fulvic acid (FAH n ) on the stability of its complexes with Cu(II), and on the equivalent weight (EW) of the ligand are presented.…”