“Electronic tongue” multi-systems for the separate determination of cefotaxime and cefazoline

Electroanalytical properties of unmodified and modified by polyaniline and by CuO nanoparticles solid-contact potentiometric sensors which are based on associates of tetradecylammonium with complex compounds of silver (I) with cephuroxime, cephotaxime and cephazoline Ag(β-lac)2TDA in solutions of corresponding antibiotics were studied. It was revealed that Ag(β-lac)2TDA –based sensors had no specificity to the basic ion but showed sensitivity to other cephalosporins. Taking into account the potentiometric selectivity coefficients and cross-sensitivity parameters of sensors based on different electrode-active components, their use for creating «electronic tongue» multi-sensor systems was shown. Arrays of low-selective potentiometric sensors were created for separate determination of cephazoline and cephotaxime in two-component model mixtures at concentration intervals of 2,5·10-4 – 0,01 М. The method of artificial neural networks was used for processing analytical signals (the relative error of determination not exceeding 13%).

Dopamine/2-Phenylethylamine Sensitivity of Ion-Selective Electrodes Based on Bifunctional-Symmetrical Boron Receptors

Piperazine-based compounds bearing two phenylboronic acid or two benzoxaborole groups (PBPA and PBBB) were applied as dopamine receptors in polymeric membranes (PVC/DOS) of ion-selective electrodes. The potentiometric sensitivity and selectivity of the sensors towards dopamine were evaluated and compared with the results obtained for 2-phenylethylamine. Since the developed electrodes displayed strong interference from 2-phenylethylamine, single-molecule geometry optimizations were performed using the density functional theory (DFT) method in order to investigate the origin of dopamine/2-phenylethylamine selectivity. The results indicated that phenylboronic acid and benzoxaborole receptors bind dopamine mainly through the dative B–N bond (like 2-phenylethylamine) and the potentiometric selectivity is mainly governed by the higher lipophilicity of 2-phenylethylamine.

Correlating the potentiometric selectivity of cyclosporin-based electrodes with binding patterns obtained from electrospray ionization-mass spectrometry

Electrospray ionization mass spectrometry ESI-MS is a powerful technique for screening ionophore binding selectivities in sensors applications.

Novel all-solid contact Copper (II) - selective sensor based on Cefoperazone and poly (3,4 -ethylenedioxythiophene) (PEDOT) as conducting polymer

A potentiometric all-solid contact copper (II) selective sensor based on Cefoperazone as a neutral carrier was developed. The electrode was prepared by coating the membrane solution containing PVC, plasticizer, and carrier on the surface of gold wire electrode. The coated gold Wire electrode (CGWE) exhibited a linear response of 31.01± 0.1 mV/decade over the range of 1.0x10–8 – 1.0 x10–2 Cu (II) mol.L-1, and lower detection limit (LDL) 4.0 x 10–9 mol.L-1. The solid-contact Cu (II) solid electrode with conducting polymer poly (3,4-ethylenedioxythiophene) (PEDOT), as intermediate layer has been successfully used to detect ions at nanomolar level concentrations. The electrode has a response time between 5-10 s and was suitable for Cu (II) determination in aqueous solution over pH range (4.0–7.0). It was found to be selective towards Cu (II) ions over other common cations and the relevant potentiometric selectivity coefficients were calculated. The analytical utility of the proposed electrode was also demonstrated.