Potentiometric titrations are direct titrations based on principle acid-base titrations, redox reaction or precipitation titrations. The voltage across the substance in electrolyte solution is measured. The specific combination of electrodes, the neutral electrodes and reference electrodes are used to measure the voltage change. The test samples are dissolved in the proper solvent according to monograph, while the automatic electronic burette dispenses the certified titrant into the testing vessel. The millivoltage and dispense volume is recorded. The automatic potentiometric titration is used to perform USP/NF monograph assay and purity.