A simple voltammetric method using a glassy carbon working electrode was developed for the determination of two members from the neonicotinoid group of insecticides: imidacloprid and thiamethoxam. The experiments showed that the voltammetric response depends on the mode of electrode surface pretreatment and the polarization mode. The response appeared to be linear in the range from 0.028 to 0.50 mg/cm3 for both analyses. The limit of detection was 0.0077 mg/cm3 for imidacloprid and 0.0085 mg/cm3 for thiamethoxam, the limit of quantitation was 0.026 mg/cm3 and 0.028 mg/cm3, respectively. The developed method was applied for the determination of these insecticides in potato samples sprayed with Confidor 200-SL or Actara 25-WG as well as commercial formulations of imidacloprid and thiamethoxam. A recovery trial was performed to assess the accuracy of the results, the recovery values being between 95?102 % for both of neonicotinoids.

Magnesium was underpotentially deposited on aluminium electrodes from magnesium nitrate-ammonium nitrate melts at temperatures ranging from 390 K to 500 K. Electrochemical techniques used were linear sweep voltammetry and potential step. Electrodes were studied by Scanning electron microscopy (SEM), Energy dispersive spectrometry (EDS), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). It was found that reduction processes of nitrate, nitrite and water (when present), in the underpotential range studied, took part simultaneously with magnesium underpotential deposition. Consequently, magnesium UPD reduction and stripping voltammetry peaks were not pronounced and well defined. Nevertheless, EDS, EDX and XRD measurements showed evidence of Mg2Al3, MgAl2 and Al12Mg17 alloys formed by underpotential deposition of magnesium onto aluminium substrate. [Projekat Ministarstva nauke Republike Srbije, br. ON 172060]

The reaction of warm EtOH solutions of FeX 3 . nH 2 O (X = Cl, NO 3 ) with tridentate ONX (X = O, S, N) pyridoxal semi-, thiosemi-and S-methylisothiosemicabazones (H 2 L 1 , H 2 L 2 , H 2 L 3 , respectively) yielded high-spin octahedral mono-and bis(ligand) complexes of the formula. H 2 O. The compounds were characterized by elemental analysis, conductometric and magnetochemical measurements, IR and UV-Vis spectra. Besides, a detailed voltammetric study of the complexes was carried out in DMF solution in the presence of several supporting electrolytes, to characterize the nature of the electrode processes and solution equilibria.