Sanxin PH5 Pocket-Style pH Meter

Overview

The Sanxin PH5 is a compact, rugged pocket-style pH meter engineered for reliable field and routine laboratory measurements of aqueous solutions. Utilizing a lithium glass pH-sensitive electrode with low drift and rapid response kinetics, the PH5 operates on the fundamental principle of potentiometric measurement—detecting the potential difference across a pH-selective membrane relative to a stable internal reference. Its extended pH range (–2.00 to 16.00 pH) accommodates both strongly acidic and highly alkaline samples encountered in industrial process monitoring, environmental sampling, and aquaculture management. Integrated automatic temperature compensation (ATC) ensures accurate pH readings across 0–50 °C without manual correction, while the intelligent microprocessor architecture supports real-time diagnostics, auto-hold functionality, and configurable operational parameters—making it suitable for unattended or semi-skilled operation in non-clinical settings.

Key Features

• Lithium glass pH electrode with replaceable design—optimized for stability, fast equilibration (<15 s typical), and minimal thermal drift in ambient conditions
• Tri-color backlit STN LCD display: blue (measurement mode), green (calibration mode), red (alarm state)—enabling intuitive visual status recognition at a glance
• 1–3 point auto-calibration using standard NIST-traceable or China-standard pH buffers (4.00, 7.00, 10.01)—with automatic slope and offset validation
• IP67-rated enclosure—fully dust-tight and submersible up to 1 m for 30 minutes; instrument floats on water surface, enabling safe use near open reservoirs or in humid outdoor environments
• Extended functionality including ORP (mV) measurement (±1000 mV, 1 mV resolution), temperature logging (0–50 °C, ±0.5 °C accuracy), and programmable alarms for out-of-specification readings
• Configurable system settings: buffer set selection (DIN/USA/China/NIST), alarm thresholds, auto-off delay (1–60 min), backlight timeout (5–60 s), and hold activation mode
• Energy-efficient power management: >200 hours of continuous operation on four AAA alkaline cells; low-battery indicator with flashing icon and audible alert (if enabled)

Sample Compatibility & Compliance

The PH5 is validated for direct immersion measurement in clean to moderately conductive aqueous media—including hydroponic nutrient solutions, aquaculture ponds, swimming pool and spa water, municipal wastewater effluents, cooling tower circulation fluids, and beverage production lines. It is not intended for non-aqueous solvents, viscous suspensions, or high-protein matrices without appropriate electrode conditioning. While not certified for GLP/GMP-regulated clinical diagnostics, its calibration traceability aligns with ISO 8655-5 (volumetric calibration) and ASTM D1293 (standard test method for pH of water). The use of Chinese-standard calibration buffers complies with JJG 919–2008 (Chinese metrological verification regulation for pH meters). For regulatory environments requiring audit trails, users should maintain manual calibration logs per ISO/IEC 17025 requirements.

Software & Data Management

The PH5 operates as a standalone instrument with no Bluetooth, USB, or PC connectivity. All data handling is local and real-time: measurements are displayed and held on-screen, with no internal memory or export capability. Users must manually record values or integrate with external loggers via visual readout. However, its robust firmware includes self-diagnostic routines that verify electrode impedance, calibration slope (%), asymmetry potential, and ATC sensor integrity before and during measurement—reducing operator error and supporting compliance with basic quality assurance protocols. The absence of digital interfaces simplifies validation in regulated contexts where electronic records are not mandated.

Applications

• Environmental field testing: surface water, groundwater, and wastewater pH screening per EPA Method 150.1
• Aquaculture and hydroponics: daily monitoring of nutrient solution pH to maintain optimal ion availability for plant and fish health
• Recreational water management: routine verification of pool/spa pH within WHO-recommended 7.2–7.8 range
• Industrial water treatment: boiler feedwater, cooling tower blowdown, and RO pre-treatment stage control
• Education and vocational training: hands-on electrochemistry labs emphasizing Nernst equation fundamentals and calibration best practices
• Food & beverage QA: preliminary pH checks in juice, dairy, and brewing processes where rapid pass/fail assessment is required

FAQ

What buffer standards does the PH5 support?
The PH5 is factory-configured for Chinese national buffer standards (pH 4.00, 7.00, 10.01 at 25 °C), but users may select alternate buffer sets (DIN, USA, NIST) via the setup menu.
Can the PH5 measure samples below 0 °C or above 50 °C?
No—the integrated ATC sensor and electrode specification are rated only for 0–50 °C. Measurements outside this range require external temperature correction or alternative instrumentation.
Is the electrode replaceable, and what type is recommended?
Yes—the lithium glass pH electrode is user-replaceable (Sanxin model E-101-Li). Replacement electrodes are shipped dry and require 2-hour rehydration in 3 M KCl prior to first use.
Does the PH5 meet FDA 21 CFR Part 11 requirements?
No—it lacks electronic signature capability, audit trail generation, and secure user authentication; it is intended for non-GxP environments where paper-based records suffice.
How often should calibration be performed?
Daily calibration is recommended for critical applications; for general-purpose use, calibration before each measurement session—or when ambient temperature changes by >5 °C—is sufficient per ISO 7888 guidance.