Yoke PHB-8 Portable Pen-Type pH Meter

Overview

The Yoke PHB-8 is a compact, handheld pen-type pH meter engineered for rapid, field-deployable, and routine laboratory pH measurements in aqueous solutions. Based on potentiometric measurement principles, the device determines hydrogen ion activity by measuring the potential difference between a pH-sensitive glass membrane and a stable internal reference electrode—both integrated into the E-300 combination electrode. Its micro-power integrated circuit architecture enables ultra-low current draw, supporting extended operational life without compromising measurement stability or thermal drift performance. Designed for simplicity and reliability, the PHB-8 delivers direct-read pH values with no external calibration hardware or software required—making it suitable for quality control technicians, environmental field staff, aquarium managers, hydroponic growers, and educational laboratories where portability, ease of use, and consistent repeatability are essential.

Key Features

• Compact pen-form factor with ergonomic, pocket-sized housing (diameter ≈ 18 mm, length ≈ 160 mm), enabling one-handed operation and storage in standard lab coat pockets or tool kits.
• Triple-CR2032 lithium coin cell power system (9 V total), delivering >1500 hours of typical continuous use under ambient conditions (25 °C, 50% duty cycle), with automatic sleep mode to extend battery service life.
• Integrated E-300 combination pH electrode featuring a low-resistance glass membrane, Ag/AgCl reference system, and ceramic junction—optimized for fast response (<30 seconds to 95% stabilization) and minimal drift (<0.02 pH/hour).
• Digital LCD display with backlight-independent contrast, showing pH value to 0.01 resolution and temperature (°C) when used with optional temperature compensation probe (not included).
• Manual two-point calibration (pH 4.01 and pH 7.00 buffers recommended) via push-button interface; calibration data retained in non-volatile memory after power-off.
• IP67-rated housing (when cap is secured), providing dust-tight and immersion-resistant protection up to 1 m for 30 minutes—suitable for humid environments and occasional splash exposure.

Sample Compatibility & Compliance

The PHB-8 is validated for use with standard aqueous electrolyte solutions, including tap water, buffer standards, nutrient solutions, wastewater effluents, and mild acidic/basic process streams (pH 0–14). It is not intended for non-aqueous solvents, highly viscous media, or solutions containing high concentrations of fluoride, sulfide, or proteins that may poison the glass membrane. The instrument complies with IEC 61010-1:2010 for electrical safety in laboratory equipment and meets CE marking requirements for electromagnetic compatibility (EMC Directive 2014/30/EU). While not certified to ISO/IEC 17025 for accredited testing, its ±0.1 pH accuracy aligns with ASTM D1293–22 (Standard Test Method for pH of Water) for field-level monitoring applications. Calibration traceability follows NIST-traceable pH buffer standards (e.g., NIST SRM 186, 188).

Software & Data Management

The PHB-8 operates as a standalone, firmware-embedded instrument with no Bluetooth, USB, or PC connectivity. All calibration coefficients, date/time stamp (manual entry only), and last-calibration status are stored in on-chip EEPROM. No proprietary software or drivers are required. For regulated environments requiring audit trails (e.g., GLP or GMP labs), users must manually record calibration events, buffer lot numbers, and measurement results in bound logbooks or LIMS-integrated forms. Optional accessories include a calibration stand with dual-buffer wells and a protective carrying case with desiccant chamber for electrode storage.

Applications

• Environmental field testing: surface water, groundwater, stormwater runoff, and wastewater treatment influent/effluent monitoring per EPA Method 150.1.
• Aquaculture and aquarium maintenance: real-time pH tracking during feeding cycles, water changes, and CO₂ injection management.
• Hydroponics and greenhouse operations: nutrient solution pH verification prior to delivery to root zones.
• Education: undergraduate chemistry and biology labs for introducing electrochemical sensing fundamentals and buffer behavior.
• Food service and beverage prep: quick-check verification of sanitizing solution pH (e.g., chlorine-based cleaners at pH 6.5–7.5) in compliance with FDA Food Code Annex 4.
• Small-scale manufacturing QA: incoming raw water checks, rinse bath validation, and final product rinse water release testing.

FAQ

What is the recommended calibration frequency for the PHB-8?

For routine use, calibrate before each measurement session or at least once per day. In high-precision or regulatory contexts, perform calibration before and after each set of samples, using fresh, unexpired buffer solutions.
Can the E-300 electrode be replaced separately?

Yes—the E-300 is a user-replaceable screw-threaded electrode module. Replacement units are available directly from Yoke Instrument Co., Ltd. and maintain full mechanical and electrical compatibility with the PHB-8 body.
Does the PHB-8 support automatic temperature compensation (ATC)?

No—ATC requires an integrated temperature sensor. The PHB-8 provides manual temperature input (°C) for user-applied correction using standard pH-temperature lookup tables, but does not include built-in thermistor or digital temperature sensing.
Is the device suitable for measuring pH in soil slurries or dairy products?

Not directly—soil and dairy matrices require specialized electrodes (e.g., flat-surface or food-grade probes) and sample preparation (filtration, dilution, homogenization). The PHB-8’s E-300 electrode is optimized for clear, low-suspended-solids aqueous solutions.
How should the electrode be stored when not in use?

Store the E-300 electrode immersed in 3 M KCl storage solution or pH 4.01 buffer. Never store dry or in distilled water, as dehydration or leaching of the reference electrolyte will degrade response time and accuracy.