Determination of Iron(III) in N-Methyldiethanolamine Media Utilized in Sweetening Plant of Gas Treating Industry by Using Self-Assembled Monolayer on Gold Electrode

Determination of iron(III) in N-methyldiethanolamine activated by piperazine (a-MDEA) utilized in sweetening plant of gas treating industry is described by preparation of gold 2-mercaptosuccinic acid self-assembled monolayer electrode and characterized by cyclic voltammetry and square wave voltammetry methods. The square wave voltammograms showed a sharp peak around positive potentials +0.180 V that was used for construction of the calibration curve. Factors were optimized for iron(III) stripping analysis and optimal condition was frequency of 35 Hz, step potential of 14 mV, amplitude of 40 mV, pH =3, and preconcentration time of 10 min. A calibration curve was obtained for iron(III) in a-MDEA in a linear range of 1.25 × 10-6 to 2.69 ×10-5 mol L-1. The detection limit was found to be 1.94 × 10-7 mol L-1. The relative standard deviation (RSD) of 3.29 % for n = 6 at 1.79 × 10-5 mol L-1 iron(III) in a-MDEA media was observed in the best conditions. The presented procedure was successfully applied for determination of iron(III) content in the real samples from sweetening plant of gas treating industry.