HORIBA PH22 Portable Pen-Style pH Meter
| Brand | HORIBA |
|---|---|
| Origin | Japan |
| Model | PH22 |
| Instrument Type | Pen-Style pH Meter |
| Parameter Type | Single-Parameter (pH) |
| Measurement Range | 0.00–14.00 pH |
| Resolution | ±0.01 pH |
| Accuracy | ±0.01 pH |
| Calibration Solutions | pH 4.01 and pH 7.00 standard buffers |
| Temperature Compensation | Automatic (ATC) |
| Electrode Design | Flat-Surface pH Sensor |
| Minimum Sample Volume | 100 µL |
| Compliance | Designed for routine QC, field testing, and GLP-aligned workflows |
Overview
The HORIBA PH22 is a compact, pen-style portable pH meter engineered for rapid, reliable single-parameter pH measurement in diverse field and laboratory environments. Based on potentiometric principle using a solid-state flat-surface pH electrode, the PH22 detects hydrogen ion activity via a stable Ag/AgCl reference system and pH-sensitive glass membrane. Its integrated automatic temperature compensation (ATC) circuit—paired with a built-in NTC thermistor—ensures pH readings are corrected to 25 °C across the operational temperature range (0–50 °C), minimizing thermal drift without manual recalibration. Designed for trace-volume applications, the flat electrode geometry enables direct contact measurement of low-volume or semi-solid samples—including water films on soil surfaces, food surface exudates, and micro-volume aqueous solutions—as small as 100 µL. The device complies with fundamental metrological requirements outlined in ISO 7888 (water quality — determination of pH) and supports documentation practices aligned with ISO/IEC 17025 and FDA 21 CFR Part 11 when used within validated procedural frameworks.
Key Features
- Flat-surface pH electrode architecture optimized for surface contact measurements and minimal sample disturbance
- Automatic temperature compensation (ATC) with real-time correction from 0 °C to 50 °C
- High-resolution digital display showing pH values to two decimal places (0.01 pH resolution)
- Stable calibration retention after two-point calibration using standard pH 4.01 and pH 7.00 buffer solutions
- Rugged, waterproof IP67-rated housing suitable for humid, outdoor, or splash-prone environments
- Single-button operation with auto-power-off after 10 minutes of inactivity to extend battery life
- Replaceable electrode module with standardized BNC-compatible interface for long-term serviceability
Sample Compatibility & Compliance
The PH22 accommodates a broad spectrum of sample matrices without requiring dilution or homogenization: aqueous solutions (tap water, wastewater, nutrient media), semi-solid materials (moist soil slurries, cheese rinds, fruit pulp), and thin liquid films (aquaculture pond surface layers, leaf surface leachates). Its flat electrode eliminates air bubble entrapment issues common with conventional bulb-type sensors, improving reproducibility in heterogeneous or viscous samples. While not certified for regulatory submission under GMP or USP , the instrument meets functional performance criteria referenced in ASTM D1293 (Standard Test Method for pH of Water) and supports internal quality control procedures compliant with ISO 9001 and ISO 14001 environmental management systems. Calibration verification logs can be manually recorded to satisfy basic GLP documentation requirements.
Software & Data Management
The PH22 operates as a standalone, embedded-system instrument with no onboard data logging or Bluetooth connectivity. All measurement data remain non-stored and non-transmittable—consistent with its design intent as a rapid-check field tool. Users are expected to record results manually or integrate readings into external LIMS or Excel-based tracking templates. For laboratories requiring audit trails, the device supports periodic calibration verification against traceable NIST-certified buffer standards; calibration dates, buffer IDs, and slope/mV offset values should be documented per organizational SOPs. No firmware updates or software drivers are required—operation is fully self-contained upon battery installation.
Applications
- Aquaculture and freshwater monitoring: real-time pH profiling of pond, tank, and recirculating aquaculture system (RAS) water
- Agricultural soil health assessment: surface pH estimation of moist topsoil and compost piles
- Food safety and quality control: spot-checking surface acidity of dairy products, fermented foods, and produce
- Environmental field screening: rapid pH evaluation of runoff, leachate, and stormwater samples
- Educational laboratories: introductory electrochemistry demonstrations and student-led water quality investigations
- Facility maintenance: verification of cleaning solution neutrality or sanitizer residual pH in pharmaceutical cleanrooms
FAQ
Does the PH22 support three-point calibration?
No—the PH22 is designed exclusively for two-point calibration using pH 4.01 and pH 7.00 standard buffers. Three-point calibration is not supported due to fixed internal slope and offset algorithms.
Can the electrode be immersed in organic solvents?
No—prolonged exposure to alcohols, acetone, or chlorinated hydrocarbons may damage the pH-sensitive glass membrane and reference junction. Only aqueous or aqueous-miscible samples are recommended.
Is the electrode replaceable independently of the main unit?
Yes—the flat-surface electrode module is user-replaceable using a standard torque screwdriver; replacement part number is HORIBA E-201F-PEN.
What battery type does the PH22 use, and what is its typical service life?
It uses a single CR2032 lithium coin cell, providing approximately 2,000 measurements or 12 months of standby operation under typical usage conditions.
Does the PH22 comply with FDA 21 CFR Part 11 for electronic records?
No—it lacks electronic signature capability, audit trail generation, or data export functionality; it is intended for non-GxP preliminary screening only.
