Liquid-Liquid Microextraction of Vanadyl Porphyrins by Nano-baskets

The novelties of this approach are introducing the self-settled dispersive liquid-liquid microextraction technique to remove the centrifuging step, conducting the dispersive liquid phase microextraction in complex organic systems, applicability of water as disperser phase, and nano-extraction of charged porphyrins by nano-baskets of calixcrown, which act as the settling agents as well as the inclusion ligands. Four proton di-ionizable diacid conformers of 25,26-bis(carboxymethoxy)calix[4]arene-27,28-crown-3; -crown-4; -crown-5; and -crown-6 in the cone conformation were synthesized and used. The related parameters including ligand concentration, volume of water disperser, salt effect, and extraction time were optimized. The linear range, detection limit (S/N = 3) and precision (RSD, n = 6) were determined to be 0.2–50, 0.07 μgL 1 and 5.3%, respectively. The established method was applied to determine the target compound in five samples of live crude oil, were sampled from an Iranian offshore field. Owing to the overall differences (such as organic media, inclusion extraction, water-soluble ligands, etc), the comparison of the proposed method with the traditional liquid-liquid microextraction was inapplicable. These results revealed that the new approach is competitive analytical tool and an alternative of the traditional methods in the crude oil and related systems.