The Ammonium Ion-Selective Electrode (ISE) can be used to measure the concentration of Ammonium (NH4+) in aqueous samples. Specifications Range: 1 to 18,000 mg/L or ppm Accuracy: ±10% of full scale (calibrated 1 to 100 mgL) pH range: 4 to 7.5 Interfering ions: K+ Electrode slope (log voltage vs. concentration): +56 mV/decade Electrode resistance: 1 to 4 MΩ Temperature range (can be placed in): 0 to 50°C (no temperature compensation) Minimum immersion: 1.1 inch Electrode length: 155 mm Body diameter: 12 mm Cap diameter: 16 mm Cable length: 100 cm