Carriers For Membrane Electrodes Research Articles

Arylboronic compounds - novel carriers for catecholamine selective membrane electrodes

Arylboronic acids are used as novel carriers for membrane electrodes suitable for direct potentiometric determination of the catecholamine drug dobutamine. The carriers are capable of binding diol groups of catecholamines; solvent extraction data confirm the formation of an 1 : 1 complex. For the electrode based on octyloxyphenylboronic acid, the slope of electrode function is S = 58 mV decade–1; the detection limit is 1.7 · 10–5 mol/L, the linear range 5 · 10–4– 1 · 10–2 mol/L, the response time 10–20 s. The results suggest the potential use of boronic carriers for the detection of biogenic catecholamines.

Copper(II)-selective membrane electrodes based on o-xylylene bis(dithiocarbamates) as neutral carriers

o-Xylylene bis(diisobutyl- and methyloctadecyl-dithiocarbamate) were synthesised and used as neutral carriers in membrane electrodes to improve the selectivity for Cu2+. The electrodes based on these ionophores, with o-nitrophenyl octyl ether as a plasticising solvent mediator and potassium tetrakis-(p-chlorophenyl)borate as an anion excluder, exhibit a linearity range of 10–1–10–6Mand have a Nernstian slope of 28–29 mV per decade at 25 °C. The highly selective electrode based on o-xylylene bis(diisobutyldithiocarbamate) rejected the interference of alkali, alkaline earth and transition metal cations by a factor in the range 102–104 and showed a high selectivity for Cu2+ even in chloride and bromide media. The properties of the electrodes are discussed and also compared with those of o-xylylene bis(diethyldithiocarbamate) under similar measurement conditions.