Electrochemical behaviour of EOP at the liquid/liquid interface and its determination

A new approach to the determination of emulsifier OP (EOP, a nonionic surfactant) is proposed, based on the voltammetry of the EOP facilitating Ca2+ transfer across the water/nitrobenzene (w/nb) interface. The peaks obtained with cyclic voltammetry at the w/nb interface correspond to the transfer of the coordination complex ion [Ca(EOP)]2+ from the aqueous to the nonaqueous phase. The calibration graph is linear in the range of 1.5×10−5–5×10−4 mol l−1. The ionic surfactants have a very minor effect on detection.