Abstract: The invention provides a method of monitoring reagent levels in aqueous copper electrolytic solutions. To determine the amount of glue present in an electrowinning solution, potential is applied, decreasing in a cathodic direction (more negative) to initiate a first cycle peak. The first cycle peak is compared to a known to determine amount of glue in the solution. Additionally, voltage is cycled between upper and lower voltages to monitor glue/lignosulfonate ratios. Hysteresis and cycle stability are measured at reference voltages and compared to known hysteresis and cycle stability values to monitor glue/lignosulfonate ratio of electrolytic solutions.