Hach AN-ISE sc Ammonia-Nitrate Combined Ion-Selective Electrode Analyzer

Overview

The Hach AN-ISE sc is a dual-parameter, online-capable ion-selective electrode (ISE) analyzer engineered for continuous, real-time monitoring of ammonia nitrogen (NH₄⁺-N) and nitrate nitrogen (NO₃⁻-N) in natural waters, wastewater effluents, and industrial process streams. Unlike colorimetric or enzymatic methods, the AN-ISE sc employs potentiometric measurement principles—leveraging selective membrane electrodes that generate voltage potentials proportional to the logarithm of target ion activity in solution (per the Nernst equation). Each sensor—AISE sc for ammonium and NISE sc for nitrate—is a fully integrated, self-contained cartridge (CARTRICAL™ technology) housing three co-located sensing elements: a primary ion-selective electrode, a reference electrode (pH-compensated Ag/AgCl), and a precision thermistor. This tri-electrode architecture enables on-the-fly cross-parameter compensation—minimizing drift caused by pH fluctuations, temperature gradients, and ionic strength variations—thereby delivering stable, interference-resilient measurements without chemical reagents or sample digestion.

Key Features

• Integrated CARTRICAL™ sensor cartridges: Pre-calibrated, field-replaceable modules combining ISE, reference, and temperature electrodes in a single sealed assembly.
• No reagents, no pumps, no filters: Eliminates consumables, mechanical complexity, and associated failure points—reducing total cost of ownership and operational downtime.
• True plug-and-play integration: Designed exclusively for Hach’s SC-series digital controllers (SC100, SC200, SC1000); auto-recognizes sensor type, loads calibration coefficients, and configures measurement parameters upon insertion.
• Minimal maintenance protocol: Cartridges require replacement approximately twice annually under typical ambient conditions; no electrolyte refills, membrane cleaning, or internal recalibration needed between changes.
• Fully submersible construction: 316 stainless steel body with chemically resistant Ryton® end caps; rated for continuous immersion in aggressive aqueous environments including activated sludge, leachate, and surface water.
• Flexible deployment options: Supplied with rod-mount, chain-suspension, and wall-mount hardware kits—enabling rapid installation in channels, tanks, wet wells, or open-water buoys.

Sample Compatibility & Compliance

The AN-ISE sc operates across a broad range of water matrices—including raw influent, secondary effluent, tertiary treated water, groundwater, and surface runoff—without filtration, acidification, or dilution. Its robust ISE design tolerates suspended solids up to 500 mg/L TSS and organic loading typical of municipal and industrial wastewater. While not intended for highly viscous or abrasive slurries, it complies with standard field-deployment requirements outlined in ISO 5667-3 (water sampling) and supports data integrity practices aligned with EPA Method 350.1 (ammonia) and EPA Method 353.2 (nitrate) for screening-level verification. When paired with an SC1000 controller equipped with audit-trail firmware, the system meets foundational data governance expectations for GLP-compliant environmental monitoring programs.

Software & Data Management

All configuration, calibration, diagnostics, and data logging are managed via Hach’s SC-series controller interface—accessible locally through the controller’s LCD keypad or remotely via Modbus RTU/ASCII, Modbus TCP/IP, or Hach’s LinkComm™ software suite. The system supports scheduled automatic zero/span checks using user-defined standards, stores ≥12 months of high-resolution time-stamped readings (including raw mV outputs, compensated concentrations, temperature, and pH), and exports CSV-formatted logs compatible with LIMS and SCADA platforms. Audit trails record all parameter modifications, calibration events, and cartridge replacements—supporting traceability requirements under ISO/IEC 17025 and facilitating FDA 21 CFR Part 11 readiness when deployed with appropriate electronic signature controls.

Applications

• Wastewater treatment plant nitrification/denitrification process control—monitoring NH₄⁺-N depletion and NO₃⁻-N accumulation across bioreactors and clarifiers.
• Drinking water source protection—detecting agricultural runoff-induced nitrate spikes in reservoirs and aquifers.
• Industrial pretreatment compliance—verifying ammonia limits prior to discharge into municipal sewer systems.
• Research-grade nutrient flux studies—long-term deployment in mesocosms, wetlands, or riverine networks requiring low-maintenance, high-temporal-resolution data.
• Regulatory reporting support—providing continuous, defensible concentration records for NPDES permit compliance and state water quality assessments.

FAQ

Does the AN-ISE sc require sample filtration or pH adjustment before measurement?
No. The sensor is designed for direct immersion and measures unfiltered, untreated samples. Built-in pH compensation eliminates the need for external pH adjustment.
How often must the sensor cartridge be replaced?
Under typical wastewater or surface water conditions, replacement is recommended every 4–6 months—approximately twice per year—to maintain measurement fidelity and minimize drift.
Can the AN-ISE sc operate in seawater or high-salinity environments?
While the sensor housing is corrosion-resistant, elevated chloride and sodium ion activity may affect nitrate electrode selectivity and long-term stability; performance validation is advised for salinities >5 ppt.
Is compressed air cleaning mandatory?
No—it is optional. The air-purge cleaning kit mitigates biofilm buildup in high-fouling applications but is not required for clean water or intermittently exposed installations.
Which Hach controllers are compatible with the AN-ISE sc?
Only SC100, SC200, and SC1000 digital controllers—each providing native support for CARTRICAL™ sensor recognition, automated calibration routines, and multi-parameter display logic.