Hanna HI98120 Portable ORP and Temperature Meter

Overview

The Hanna HI98120 is a compact, handheld dual-parameter meter engineered for reliable field and laboratory measurement of oxidation-reduction potential (ORP) and temperature in aqueous solutions. Based on the principle of potentiometric measurement, the instrument determines ORP by measuring the voltage difference between a noble-metal sensing element (typically platinum or gold) and a stable internal reference electrode—expressed in millivolts (mV) relative to the Standard Hydrogen Electrode (SHE). Simultaneously, an integrated NTC thermistor provides real-time temperature compensation, ensuring accurate ORP interpretation across varying thermal conditions. Designed for routine water quality verification, the HI98120 delivers traceable, repeatable results without requiring complex setup or external accessories. Its solid-state construction and sealed electronics meet industrial demands for durability in humid, splash-prone environments—making it suitable for wastewater monitoring, aquaculture system checks, swimming pool maintenance, and pretreatment validation in pharmaceutical or food-grade process water loops.

Key Features

• Integrated ORP and temperature sensor eliminates cable management and interfacial resistance errors common with separate probes
• IP67-rated housing ensures full protection against dust ingress and immersion in up to 1 m of water for 30 minutes
• Auto-ranging display with clear backlighting supports operation under low-light field conditions
• Single-point offset calibration using certified ORP standards (e.g., +225 mV or +430 mV Zobell solution) enables rapid verification prior to critical measurements
• Battery life exceeds 200 hours under typical usage; low-battery indicator prevents data interruption during extended surveys
• No user-serviceable parts—designed for long-term stability without recalibration drift beyond specification limits

Sample Compatibility & Compliance

The HI98120 is validated for use with clean to moderately turbid aqueous samples, including drinking water, surface water, effluent streams, cooling tower fluids, and hydroponic nutrient solutions. It is not intended for use in highly viscous, non-aqueous, or strongly oxidizing media (e.g., concentrated chlorine solutions >100 ppm free chlorine without dilution). The device complies with EU Directive 2014/30/EU (EMC) and 2011/65/EU (RoHS), carries CE marking, and conforms to IEC 60529 for ingress protection. While not FDA 21 CFR Part 11–compliant (as it lacks audit trail or electronic signature functionality), its measurement traceability aligns with ISO/IEC 17025–recommended practices for field instrumentation used in environmental compliance reporting under national regulatory frameworks (e.g., EPA Method 9038 for ORP screening).

Software & Data Management

The HI98120 operates as a standalone, button-driven instrument with no onboard data logging or PC connectivity. All readings are displayed in real time and must be manually recorded. This design prioritizes operational simplicity, mechanical reliability, and minimal failure points—ideal for technicians performing scheduled spot checks where digital integration is unnecessary or impractical. For laboratories requiring documentation, Hanna recommends pairing the HI98120 with external logging systems or using it alongside their HI98190 series meters, which support USB data export and GLP-compliant timestamped records. No firmware updates or software drivers are required, eliminating version control concerns in multi-unit deployments.

Applications

• Verification of disinfection efficacy in municipal water distribution networks via ORP correlation with free chlorine residual
• Monitoring redox conditions in anaerobic digesters and denitrification basins to optimize biological treatment efficiency
• Quality assurance testing of rinse water in semiconductor fab wet benches where ORP thresholds indicate contaminant carryover
• Routine assessment of electrochemical stability in electroplating bath formulations
• Field validation of ORP probe performance before deployment in fixed online analyzers
• Educational use in undergraduate environmental engineering labs for introducing redox concepts and sensor fundamentals

FAQ

Does the HI98120 require regular calibration? Why?

Yes—single-point offset calibration is recommended before each measurement session or when ambient temperature shifts exceed ±5 °C. ORP electrodes exhibit gradual potential drift due to surface fouling or reference junction clogging; calibration corrects for this offset without altering slope response.
Can this meter measure pH?

No. The HI98120 is dedicated solely to ORP and temperature. It lacks the glass membrane electrode and asymmetric potential compensation required for pH measurement.
Is the sensor replaceable?

The sensor is permanently integrated and non-user-replaceable. If sensor degradation occurs (e.g., sluggish response, unstable readings after cleaning), the entire unit must be serviced or replaced per Hanna’s warranty policy.
What ORP standard solutions are compatible with calibration?

Certified Zobell solution (+225 mV at 25 °C) or Light’s solution (+430 mV at 25 °C) are recommended. Avoid commercial “ORP buffer” tablets unless independently verified for traceability to NIST-traceable standards.
How does temperature compensation work in this device?

The built-in NTC thermistor measures sample temperature continuously and applies a fixed Nernstian correction factor (−0.198 mV/°C deviation from 25 °C) to the raw ORP signal—consistent with ASTM D1129 definitions for standardized reporting.