A method has been developed for determination of the active glue concentration in copper electrorefinery tankhouse electrolyte. The procedure is carried out in two major steps: i) separation of the active glue fraction from the tankhouse electrolyte containing other organic additives by means of ultrafine molecular filtration and ii) its subsequent quantitative determination by cathodic overpotential measurements. In contrast to earlier approaches, this method is insensitive to varying composition of the tankhouse electrolyte, and a single calibration curve can be used for interpolation of active glue concentrations from the overpotential measurements.