AlpHa Measurement Solutions |
Ion-Selective Electrodes in Environmental Monitoring
ISE in Environmental Monitoring
Specific ion measurements are critical to monitoring trends over time to understand the impact on environmental health. AlpHa offers Ion-selective electrodes (ISE) that provide real-time data, along with the ability for spot checks, easy to use for environmental monitoring. Examples where ions are important in environmental monitoring include:
- Nitrate, ammonium, ammonia ISEs measure the nitrification / denitrification of the nitrogen cycle in natural waters to determine nutrient impact
- Chloride ISE is utilized to measure the pollution impact and water quality
- Potassium ISE measurements identify fertilizer runoffs or other man-made influences to a body of water
- Water hardness, also referred to as total calcium and magnesium, identifies high mineral content
Environmental monitoring applications measure a variety of ions in the field or as grab samples in a lab. Remote stations require multiparameter sondes that continuously measure ion activity, log data, and transmit wirelessly. ISE application challenges in environmental monitoring include sensor biofouling (algae coating) and reference junction contamination. These challenges can be mitigated with the optimal sensor design, in particular the reference system and housing material. AlpHa’s ISE portfolio can target over twenty different ions which are designed for both lab and continuous process environments.
| Ion-Selective Electrode | Range @ 25°C | Technology Type | Temp. Range | Warranty |
| Ammonia (NH3) | 0.01 – 17,000 ppm as NH3 | Gas Sensing | 0 – 50°C | 12 Months |
| Ammonium (NH4+) | 0.1 – 14,000 ppm as N | PVC Membrane | 0 – 40°C | 6 Months |
| Bromide (Br-) | 0.2 – 79,900 ppm | Solid State Pellet | 0 – 80°C | 12 Months |
| Cadmium (Cd2+) | 0.01 – 11,200 ppm | Solid State Pellet | 0 – 80°C | 12 Months |
| Calcium (Ca2+) | 0.5 – 40,100 ppm | PVC Membrane | 0 – 40°C | 6 Months |
| Carbon Dioxide (CO2) | 4.4 – 440 ppm | Gas Sensing | 0 – 50°C | 12 Months |
| Chloride (Cl-) | 1.8 – 35,000 ppm | Solid State Pellet | 0 – 80°C | 12 Months |
| Copper (Cu2+) | 0.064 – 6,400 ppm | Solid State Pellet | 0 – 80°C | 12 Months |
| Cyanide (CN-) | 0.2 – 260 ppm | Solid State Pellet | 0 – 80°C | 12 Months |
| Fluoride (F-) | 0.02 – 19,000 ppm | Solid State Crystal | 0 – 80°C | 12 Months |
| Fluoroborate (BF4-) | Varies | PVC Membrane | 0 – 40°C | 6 Months |
| Iodide (I-) | 0.01 – 127,000 ppm | Solid State Pellet | 0 – 80°C | 12 Months |
| Lead (Pb2+) | 0.2 – 20,700 ppm | Solid State Pellet | 0 – 80°C | 12 Months |
| Lithium (Li+) | 0.2 – 10,000 ppm | PVC Membrane | 0 – 40°C | 6 Months |
| Magnesium (Mg2+) | 0.1 – 30,000 ppm | PVC Membrane | 0 – 40°C | 6 Months |
| Nitrate (NO3-) | 0.1 – 14,000 ppm as N | PVC Membrane | 0 – 40°C | 6 Months |
| Nitrogen Oxide (NOx) | Varies | Gas Sensing | 0 – 50°C | 12 Months |
| Perchlorate (ClO4-) | Varies | PVC Membrane | 0 – 40°C | 6 Months |
| Potassium (K+) | 0.04 – 39,000 ppm | PVC Membrane | 0 – 40°C | 6 Months |
| Silver (Ag+) | 0.01 – 107,900 ppm | Solid State Pellet | 0 – 80°C | 12 Months |
| Sulfide (S2-) | 0.01 – 32,100 ppm | Solid State Pellet | 0 – 80°C | 12 Months |
| Sodium (Na+) | 0.01 – 100,000 ppm | Sensing Glass | 0 – 80°C | 12 Months |
| Surfactant (X+ / X-) | Varies | PVC Membrane | 0 – 40°C | 6 Months |
| Water Hardness (Ca2+ / Mg2+) | 0.5 – 40,000 ppm | PVC Membrane | 0 – 40°C | 6 Months |
- Form Factor
- 12 mm
- Process Body
- Cartridge
- Custom Options Available
- Housing Material Options
- Glass
- Ryton® (PPS)
- ABS
- Epoxy
- Polycarbonate
- Kynar® (PVDF)
- Polyethylene
- PEEK
- PVC / CPVC
- Teflon™ (PTFE)
- Ultem® (PEI)
- Custom Options Available
- Thermistor Options
- Not commonly integrated, however, optional per design requirements
- Reference System
- Ag / AgCl
- Custom Options Available
- Reference Junction Options
- Single Junction
- Double Junction
- Custom Options Available
- Reference Junction Material / Design
- Ceramic Pin / Annular / Disc
- Fiber / Pellon
- Open Aperture
- Porous Plastic (PTFE / HDPE / PP)
- Sleeve Junction / Free Flow (liquid / liquid or ground glass joint)
- Solid State
- Custom Options Available
- Reference Electrolyte
- Sealed
- Soft Gel
- Solid Gel
- Refillable
- Liquid
- Soft Gel
- Custom Options Available
- Sealed
- Integrated Insertions
- PG 13.5
- 3/4" NPT
- 1/2" NPT
- 1" NPT
- Custom Options Available
- Analog
- Millivolts
- 0 – 5 V
- 0 – 10 V
- 4 – 20 mA
- Custom Options Available
- Digital
- RS-485 MODBUS RTU
- Custom Options Available
- Connectors
- Integrated Connectors (detachable or cableless)
- S7
- S8
- Integrated BNC
- Variopin
- Custom Options Available
- Connectors with Cables (including temperature)
- BNC
- DIN
- MOLEX
- Tinned Leads
- Mil-spec
- 2.5 mm / 3.5 mm phono
- RCA
- Spade Lugs
- LEMO
- Circular Connectors
- Any commercially available connectors and custom options available
- Integrated Connectors (detachable or cableless)