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Abstract: Spinacia oleracea L. extract was immobilized on an octadecyl‐bonded silica surface to produce a new sorbent for the solid‐phase extraction of trace amounts of metal ions from aqueous neutral samples. A measurement of the metal content has been performed by using graphite furnace atomic absorption spectroscopy. The affinity of the investigated bivalent metal cations for the modified sorbent are in the order: Pb(II) > Cu(II) > Ni(II) > Zn(II) ≈ Cd(II) ≈ Co(II). The quantum‐chemically calculated chlorophyll‐a–metal ion binding energies were consistent with the measured affinities of the corresponding metal ions to the investigated sorbent. The maximum sorption capacity obtained for Pb(II) was equal to 1.44 μmol/g. The value of lead uptake was significantly higher in comparison to the one reported for other sorbents and biosorbents. Immobilized chlorophyll a is responsible for a chelation process with stoichiometry 1:1 owing to the porphyrin rings, which was confirmed by the quantitative analysis performed by reversed‐phase high‐performance liquid chromatography with diode array detection. The Toth adsorption isotherm model was applicable to the description of the adsorption process of either chlorophyll a or Pb(II). The structural analysis of sorbent was done using Fourier‐transform Raman spectroscopy and scanning electron microscopy with an energy dispersive X‐ray detector. [ABSTRACT FROM AUTHOR]

New synthesized 1,4-disubstituted thiosemicarbazide derivatives were analyzed in the RP system, modified with the addition of salts; chaotropic (sodium hexafluorophosphate - Na PF6), cosmotropic (sodium phosphate - Na H2 PO4), and neutral ( Na Cl) on Zorbax XDB C18 column. The effect of the eluent composition on the analytes retention ( k), system efficiency ( N), peak symmetry ( A s), and LOD values were all examined and compared to unmodified organic-aqueous mobile phase system. It was established that eluent modified with chaotropic salts addition was also the most advantageous according to other peak parameters such as the theoretical plates numbers and asymmetry factors. The lower LOD values were achieved in comparison to unmodified organic-aqueous eluent system. Compatibility of lipophilicity parameters calculated by the use of computer software with experimental ones measured by RP- HPLC was also the best for chaotropic modified mobile phase. To explain the observed phenomena, molecular modeling was performed for chosen representative compound in different environment representing examined mobile phase composition. [ABSTRACT FROM AUTHOR]