Ion selective electrodes have largely replaced which instrument?

• A. Flame photometry
• B. AAS
• C. ICP-MS
• D. UV-Vis spectrophotometer

Answer: (A)

Ion-selective electrodes measure a specific ion directly in solution using a selective membrane, giving rapid, point-and-click results with small sample volumes and easy automation. This makes them highly practical for routine clinical measurements of ions such as sodium, potassium, calcium, and chloride. Flame photometry, by contrast, relies on analyzing light emitted from atoms in a flame and is more dependent on flame conditions, spectral interferences, and larger, bulkier instrumentation. It’s also limited to certain elements and often requires more manual handling and preparation. Because ion-selective electrodes offer faster, more direct, and easier-to-automate measurements in complex samples, they have largely replaced flame photometry in modern clinical laboratories.