Bis(isovalerylacetone)ethylenediimine Nickel(II) as Mixed Stationary Phase for Gas Chromatography

Abstract

Bis(isovalerylacetone)ethylenediimine Nickel (II) (IVA(2)enNi) was examined as a mixed stationary phase with OV1 on Chromosorb G/NAW 60-80 mesh size for gas chromatography (GC) separation of aromatic hydrocarbons, heteroaromatics, alcohols, aldehydes, ketones, esters, nitro-, and amino compounds. Forty-six compounds were examined, and the GC results were compared with those obtained with 3% OV1 on Chromosorb G/NAW 60-80 mesh size under similar operating conditions. Improved resolutions, peak asymmetry, number of theoretical plates, and Kovats indices were obtained on the mixed stationary phase 3% OV1 + 5% IVA(2)enNi (w/w) compared to 3% OV1 column. The stability constant (K(m)), enthalpies (DeltaH), entropies (DeltaS), and Gibbs free energies (DeltaG) of the GC elution on column (2 m x 3 mm i.d.) packed with 3% OV1 + 5% IVA(2)enNi (w/w) on Chromosorb have been calculated. Donor-acceptor complexation in the gas phase indicated by the negative values of enthalpy (-DeltaH) were within 9.4-12.38 Kcal/mol, and Gibbs free energy (-DeltaG) ranged from 1.48 to 4.24 Kcal/mol. The retention time transformation on both the phases were calculated. The obtained ratios from the stationary phases 3% OV1 and 3% OV1 + 5% IVA(2)enNi (w/w) were plotted on the x-axis and y-axis, respectively. Two-dimensional chromatographic plots for alkanes, aromatics, heteroaromatics, ketones, alcohols, esters, and nitro compounds were obtained with coefficient of determination within 0.4934 and 0.9617, which is indicative of some different kinds of interaction of two stationary phases with the solutes.

Effect of substituents on prediction of TLC retention of tetra‐dentate Schiff bases and their Copper(II) and Nickel(II) complexes

“…Tetra‐dentate Schiff bases are used for determination of metal ions by gas and liquid chromatography owing to their selective reactions (Khuhawar & Soomro, ). Metal complexes are used as modified stationary phases in gas chromatography for separation of various compounds such as alcohols, ketones, aldehydes, esters, nitro‐ and amino compounds (Laghari, Khuhawar, Zeenat, & Zardar, ). They can also be used for the modification of stationary phases in HPLC separations of copper and nickel ions (Bader, Hutta, & Kuss, ).…”