Liquid-Liquid Extraction and Spectrophotometric Determination of Vanadium(V) with p-Carboxy-N-Phenyl-Calix[4]resorcinarene-hydroxamic Acid

The synthesized p-carboxy-N-phenyl-calix[4]resorcinarene-hydroxamic acid PCNPC4RAHA is reported for the extraction and preconcentration of V(V) from environmental samples in the presence of numerous ions. The extract has been subjected to the determination of V(V) by uv-vis spectrophotometry and inductively coupled plasma atomic emission spectrometry (ICP-AES). Various significant parameters like pH, concentration of V(V), concentration of reagent, and effect of solvents are optimized. The wavelength of maximum extraction (/jnax), molar absorptivity (e), linear concentration range obeying Beer's law, effect of diverse ions, limit of detection (LOD), limit of quantification (LOQ), and preconcentration factor has been determined. The two phase stability constant (log4), and thermodynamic parameters viz. G, H, and S have also been determined. The complexation of vanadium with PCNPC4RAHA is also characterized by favourable enthalpy change. The stoichiometry of metal-reagent complex has been established by modified Job's plot method. To check the validity of the proposed method, V(V) is also determined in environmental, biological samples, and some standard reference materials from NIST (National Institute of Standards and Technology) and BCS (British Chemical Standards).