Development of a potentiometric flow cell with a stainless steel electrode for pH measurements. Determination of acid mixtures using flow injection analysis.

In this work a stainless steel electrode was prepared, characterised and used as indicator electrode in a potentiometric flow cell. Due to its versatility, it was possible to study different electrode geometries and flow cell arrangements. After optimising the system, mixtures of succinic and oxalic acids were determined by titration. Partial least squares (PLS) regression as multivariate calibration tool was applied for data treatment. The predicted results obtained in a test set showed a relative error of 4.3% for succinic acid and 5.5% for oxalic acid.