ATAGO DPH-2 Portable Digital pH Meter
| Brand | ATAGO |
|---|---|
| Origin | Japan |
| Model | DPH-2 |
| Instrument Type | Portable |
| Parameter Type | Single-parameter (pH) |
| Measurement Range | 0.0 to 14.0 pH |
| Resolution | 0.1 pH |
| Accuracy | ±0.1 pH (within 2.0–12.0 pH range) |
| Temperature Range | 0.0 to 50.0 °C with Automatic Temperature Compensation (ATC) |
| Protection Rating | IP67 |
| Power Supply | Four LR44 button cells |
| Dimensions | 45 × 30 × 163 mm |
| Weight | 90 g (body only) |
Overview
The ATAGO DPH-2 Portable Digital pH Meter is a compact, field-ready electrochemical instrument engineered for rapid, reliable pH measurement of aqueous and water-soluble solutions. Based on the potentiometric principle—measuring the voltage difference between a glass pH sensing electrode and a stable reference electrode—the DPH-2 delivers traceable, repeatable results across the full physiological and industrial pH scale (0.0–14.0). Its integrated automatic temperature compensation (ATC) circuitry utilizes a built-in thermistor to correct for solution temperature drift in real time, ensuring measurement integrity between 0.0 °C and 50.0 °C without manual recalibration. Designed for rugged daily use, the meter conforms to IP67 ingress protection standards—fully dust-tight and capable of withstanding immersion in 1 m of water for up to 30 minutes—making it suitable for demanding environments including production floors, agricultural fields, and laboratory peripheries.
Key Features
- High-stability glass electrode architecture optimized for aqueous and mildly buffered water-soluble samples
- Three-point calibration capability using standard buffers at pH 4.0, 7.0, and 10.0—ensuring linearity verification across acidic, neutral, and alkaline ranges
- Digital display with 0.1 pH resolution and ±0.1 pH accuracy (validated within 2.0–12.0 pH under ISO 3696 Grade 3 water conditions)
- Automatic temperature compensation (ATC) eliminates manual correction errors and improves inter-laboratory reproducibility
- Compact ergonomic form factor (45 × 30 × 163 mm) and lightweight design (90 g body weight) facilitate one-handed operation and extended field deployment
- Low-power consumption powered by four replaceable LR44 button cells—typical battery life exceeds 10,000 measurements per set
Sample Compatibility & Compliance
The DPH-2 is validated for direct measurement of homogeneous, low-viscosity aqueous solutions—including beverages, brewing wort and mash, food extracts, cleaning agents (e.g., alkaline degreasers), metalworking coolants, soil leachates, and mild electrolyte solutions. It is not intended for non-aqueous solvents, highly viscous suspensions, or strongly oxidizing/halogenated media. The instrument complies with IEC 60529 (IP67), JIS Z 8401 (pH measurement methodology), and supports adherence to GLP documentation requirements when used with calibrated traceable buffers. While not FDA 21 CFR Part 11–compliant out-of-the-box (lacking audit trail or electronic signature functionality), its measurement output satisfies routine QC testing under ISO/IEC 17025 and ASTM E70-22 protocols for pH determination in chemical and food laboratories.
Software & Data Management
The DPH-2 operates as a standalone, microprocessor-controlled meter with no embedded data logging, Bluetooth, or USB interface. All measurements are displayed in real time on a high-contrast LCD screen; no software installation or driver configuration is required. Users must manually record readings alongside contextual metadata (sample ID, buffer lot numbers, ambient temperature) to fulfill basic traceability requirements. For regulated environments requiring electronic records, integration with external digital notebooks or LIMS systems is achieved via manual transcription or optional third-party optical character recognition (OCR) workflows. Calibration history and instrument verification can be documented using ATAGO’s recommended calibration log template (Form DPH-2-CL-01), aligned with ISO/IEC 17025 Clause 7.7.
Applications
- Quality control of beverage pH during bottling and pasteurization validation
- In-process monitoring of wort pH in craft brewing and fermentation starter preparation
- Soil extract analysis for agronomic pH assessment (saturation extract method per ASTM D4972)
- Concentration verification of alkaline cleaning solutions in pharmaceutical equipment CIP cycles
- Routine verification of coolant pH stability in CNC machining operations
- Educational laboratory exercises in general chemistry and environmental science curricula
FAQ
Does the DPH-2 support electrode replacement or user-serviceable calibration?
Yes—the meter accepts standard BNC-compatible pH electrodes with integrated ATC sensors; calibration is performed manually using supplied or certified NIST-traceable buffer solutions.
Is the device suitable for measuring pH in high-ionic-strength brines or seawater?
No—while robust for typical process streams, the DPH-2 is not optimized for extreme ionic strength (>1 mol/L NaCl) or chloride-rich matrices where junction potential drift may exceed ±0.1 pH tolerance.
What is the recommended calibration frequency for GMP-aligned use?
Per ATAGO Application Note AN-DPH-03, calibration before each measurement session and after every 10 consecutive readings is advised when operating under ISO 9001 or food safety HACCP frameworks.
Can the DPH-2 be used in explosive or hazardous atmospheres?
No—it lacks ATEX, IECEx, or UL HazLoc certification and must not be deployed in Class I Division 1 environments.
How is measurement uncertainty estimated for ISO/IEC 17025 reporting?
Combined standard uncertainty (k=2) is typically ±0.15 pH, derived from contributions of electrode slope deviation (±0.05), temperature sensor error (±0.03 °C × 0.03 pH/°C), and repeatability (±0.02 pH), as detailed in ATAGO Technical Bulletin TB-DPH-2-UNC-2023.
