1. pH Electrodes
- Core Structure: Composed of a low-impedance glass membrane (e.g., GFT EST-701Y) and an Ag/AgCl reference system with gel electrolyte, ensuring stable potential and anti-pollution performance
- Features:
- Wide measurement range (0-14 pH) with linear response.
- Suitable for harsh environments, including wastewater and high-temperature applications (e.g., -5°C to 135°C) .
- Requires regular calibration with standard buffer solutions (e.g., pH 4.01, 7.00) for accuracy
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2. Dissolved Oxygen (DO) Electrodes
- Design: Utilizes Clark-type membrane technology or optical sensors (e.g., SWAN A-87 series), often integrated with automatic temperature compensation (ATC) for real-time monitoring
- Applications:
- Ideal for aquaculture, environmental monitoring, and industrial water systems.
- Maintenance involves periodic membrane replacement and calibration with zero-oxygen solutions (e.g., sodium sulfite)
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3. Conductivity Electrodes
- Configuration: Features multi-ring (e.g., 4-ring) or graphite sensors with epoxy resin bodies for wide-range measurement (0-2000 μS/cm to 20,000 μS/cm)
- Key Parameters:
- Temperature compensation (NTC10K/PT1000) ensures accuracy across varying conditions.
- Used in pure water systems, boiler water, and chemical processes
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4. Ion-Selective Electrodes (ISE)
- Function: Measures specific ions using ion-sensitive membranes. Examples include calcium hardness electrodes (Bsens740) for industrial water monitoring
- Advantages:
- Direct measurement without reagents; minimal maintenance.
- Calibration requires standard ion solutions (e.g., 0.1M HCl for electrode reactivation)
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5. ORP (Oxidation-Reduction Potential) Electrodes
- Structure: Platinum or gold sensing elements with a double-junction reference system to prevent contamination
- Usage: Critical in disinfection (e.g., chlorine monitoring) and redox reaction analysis.
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6. Multi-Parameter Electrodes
- Integration: Combines pH, DO, conductivity, and ion sensors (e.g., ThermoFisher Eutech PCD650) for comprehensive analysis
- Features:
- Waterproof housing (IP65/IP67) for field use.
- Supports RS485/Modbus communication for data logging and remote control .
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Maintenance Guidelines:
- Calibration: Use certified standards (e.g., NIST-traceable solutions) and follow manufacturer protocols .
- Cleaning: Remove contaminants with deionized water or specific solvents (e.g., 4% HF for glass membrane scaling)
- Storage: Keep electrodes hydrated (e.g., in 3M KCl for pH electrodes) to prolong lifespan
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For detailed specifications, refer to technical manuals from brands like SWAN 6, GreenPrima , or HANNA
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