A method for measuring the concentration of the metal solution and reducing agent solution within the electroless plating solution is disclosed. Raman spectroscopy is used to measure the concentration of each solution within the electroless plating solution after they have been mixed together. By measuring the concentration of each solution prior to providing the solution to a plating cell, the concentration of the individual solutions can be adjusted so that the targeted concentration of each solution is achieved. Additionally, each solution can be individually analyzed using Raman spectroscopy prior to mixing with the other solutions. Based upon the Raman spectroscopy measurements of the individual solutions prior to mixing, the individual components that make up each solution can be adjusted prior to mixing so that the targeted component concentration can be achieved.