When sourcing ISEs, you must prioritize the Detection Limit and Linear Range to ensure the sensor covers your specific concentration needs. Key technical factors include the Slope (Sensitivity), which should ideally be close to the Nernstian value (e.g., 59.16 mV/decade for monovalent ions at 25°C), and the Selectivity Coefficient, which defines the electrode's ability to distinguish the target ion from interfering ions. Additionally, verify the Response Time (typically <30 seconds) and the pH Operating Range to prevent damage to the sensing membrane.