Hanna HI98128 Portable pH and Temperature Meter

Overview

The Hanna HI98128 is a high-precision, portable pH and temperature meter engineered for field-deployable accuracy and laboratory-grade reliability. Designed around a robust electrochemical measurement principle—potentiometric detection via glass electrode—this instrument delivers traceable, repeatable pH readings across an extended range of -2.00 to 16.00 pH. Its integrated NIST-traceable temperature sensor enables real-time automatic temperature compensation (ATC), ensuring thermally corrected pH values without manual input or external probes. Unlike basic pocket meters, the HI98128 employs a dedicated pH-glass electrode (HI73127) with a low-resistance junction and stable reference system, minimizing drift and polarization errors during extended use in aqueous, semi-aqueous, or mildly aggressive matrices. The device complies with fundamental metrological requirements outlined in ISO 7027 (for photometric comparators) and aligns with electrochemical best practices defined in ASTM D1293 (Standard Test Method for pH of Water) and USP (pH Measurement). It is routinely deployed in environmental monitoring, wastewater treatment pre-screening, educational labs, food & beverage quality control, and aquaculture management where portability must not compromise analytical integrity.

Key Features

• High-resolution dual-line LCD display with intuitive icon-driven interface and on-screen calibration guidance
• True 0.01 pH resolution and ±0.05 pH accuracy at 25°C—exceeding typical handheld meter specifications
• Two programmable calibration sets: (pH 4.01 / 7.01 / 10.01) and (pH 4.01 / 6.86 / 9.18), enabling compliance with regional standardization protocols
• Automatic buffer recognition during calibration eliminates manual buffer selection errors
• Integrated ATC using a precision thermistor (±0.5°C accuracy) referenced to the electrode tip for minimal thermal lag
• Battery Error Prevention System (BEPS) actively monitors cell voltage and disables measurement if power falls below operational threshold
• IP67-rated housing (when sealed) resists dust ingress and withstands immersion up to 1 m for 30 minutes—suitable for humid, outdoor, or industrial environments
• Quick-release battery compartment allows tool-free replacement of four LR44 cells in under 15 seconds

Sample Compatibility & Compliance

The HI98128 is validated for use with aqueous solutions, buffered standards, tap water, surface water, effluent streams, nutrient solutions, and non-viscous food extracts. Its HI73127 combination electrode features a spherical glass membrane optimized for rapid response in low-ionic-strength samples and a double-junction reference system that mitigates contamination from sulfides, proteins, or heavy metals. While not certified for hazardous area use (e.g., ATEX or IECEx), the meter meets CE marking requirements per Directive 2014/30/EU (EMC) and 2011/65/EU (RoHS). It supports GLP-compliant workflows through uneditable calibration logs stored in non-volatile memory—including date/time stamps, buffer IDs used, slope (%), and offset (mV)—accessible only via physical reset. Though not FDA 21 CFR Part 11 compliant out-of-the-box, audit trails satisfy basic ISO/IEC 17025 documentation expectations for accredited testing laboratories.

Software & Data Management

The HI98128 operates as a standalone instrument with no Bluetooth, USB, or PC connectivity. All calibration data, measurement history, and system settings are retained in onboard memory independent of power state. Each calibration event records slope (typically 95–105 %), offset (-30 to +30 mV), and ambient temperature—enabling post-hoc verification of electrode health. The device supports two user-selectable temperature units (°C or °F) and permits manual temperature override when ATC is disabled for specialized applications (e.g., fixed-temperature incubation studies). Firmware is factory-programmed and non-upgradable; however, Hanna provides full traceability documentation—including electrode certification sheets and buffer lot-specific uncertainty statements—for each shipped kit.

Applications

• Field-based environmental sampling: river, lake, and groundwater pH profiling per EPA Method 150.1
• Pre-treatment verification in municipal and industrial wastewater facilities
• Quality assurance checks for hydroponic nutrient reservoirs and recirculating aquaculture systems (RAS)
• Classroom experiments requiring NIST-traceable measurements under variable ambient conditions
• Routine monitoring of cleaning-in-place (CIP) rinse water acidity in food processing lines
• Calibration verification of benchtop pH meters using transportable reference standards

FAQ

Does the HI98128 support GLP-compliant record keeping?
Yes—the instrument stores calibration metadata (date, buffers used, slope, offset, temperature) in non-volatile memory. While it lacks electronic signature or audit trail export, these logs meet minimum documentation requirements for ISO/IEC 17025 Clause 7.7.

Can the HI73127 electrode be used in high-salinity or organic solvent-containing samples?
The electrode is designed for aqueous media. Prolonged exposure to >10% ethanol, chlorinated solvents, or saturated brine may degrade the reference junction or glass membrane. Use only with appropriate rinsing and storage in HI70300 electrode storage solution.

Is the pH accuracy specification valid across the entire -2.00 to 16.00 range?
The ±0.05 pH accuracy is verified at 25°C using certified buffers within the 2.00–12.00 pH range. Outside this span, accuracy degrades gradually due to glass membrane nonlinearity and junction potential shifts; consult Hanna Technical Bulletin TB-012 for extended-range validation data.

How often should calibration be performed?
Daily calibration is recommended for critical measurements. For routine screening, calibration before first use and after electrode replacement or prolonged storage (>24 h) satisfies ASTM D1293 and ISO 10523 guidelines.