Sanxin SX711 Portable pH Meter

Overview

The Sanxin SX711 Portable pH Meter is a field-deployable, single-parameter electrochemical analyzer engineered for high-reliability pH and redox potential (mV) measurements in demanding industrial, environmental, and municipal applications. Based on potentiometric measurement principles using a glass electrode and reference junction system, the SX711 delivers traceable accuracy across an extended pH range (−2.00 to 19.99), enabling characterization of highly acidic, neutral, and strongly alkaline aqueous media—including caustic cleaning solutions, boiler feedwater, flue gas desulfurization slurries, and wastewater effluents. Its integrated automatic temperature compensation (ATC) circuitry—operating from 0 °C to 100 °C—ensures thermally corrected readings without manual intervention, while the high-input-impedance amplifier (≥1 × 10¹² Ω) minimizes loading effects on high-resistance electrodes and low-conductivity samples such as ultrapure water or pharmaceutical process streams.

Key Features

• Microprocessor-controlled architecture with embedded diagnostics, auto-shutdown (after 10 min inactivity), and low-battery indication
• Intelligent buffer recognition supporting 13 standardized pH calibration solutions across three regional series: US/EU (DIN/ISO), NIST-traceable, and China National Standard (GB/T 27502)
• Dedicated measurement modes for high-purity water (low ionic strength compensation) and ammonia-dosed condensate systems, mitigating alkaline error and junction potential drift
• Ruggedized housing rated IP57—dust-protected and submersible up to 1 m for 30 minutes—validated for field use in wastewater treatment plants, power station perimeters, and remote monitoring sites
• Onboard data logging of 200 measurement records, each storing timestamp-equivalent ID, pH/mV value, unit, and simultaneous temperature reading
• Plug-and-play compatibility with the included 201T-S tri-combination electrode (pH sensing element + Ag/AgCl reference + built-in ATC thermistor), optimized for rapid response and mechanical durability

Sample Compatibility & Compliance

The SX711 is validated for direct immersion measurements in liquid-phase aqueous samples with conductivity ≥50 µS/cm. It supports routine compliance testing aligned with ASTM D1293 (pH of water), ISO 10523 (water quality — determination of pH), and GB/T 6920–1986 (Chinese standard for pH determination). While not inherently 21 CFR Part 11 compliant due to lack of electronic signature and audit trail capabilities, its calibration logs, stability performance (±0.01 pH over 3 h), and documented traceability to national standards satisfy GLP documentation requirements for non-regulated QC environments. The instrument’s CMC (China Metrology Certification) and CE marking confirm conformity with electromagnetic compatibility (EMC Directive 2014/30/EU) and low-voltage safety (LVD Directive 2014/35/EU).

Software & Data Management

Data export is performed manually via recorded ID-indexed entries displayed on the dual-line LCD. No proprietary software or USB interface is provided; however, logged values may be transcribed into LIMS or Excel-based QA templates. Calibration history—including date, buffer IDs used, slope (%), and offset (mV)—is retained within the device memory and accessible via menu navigation. All calibrations adhere to multi-point verification protocols defined in ISO/IEC 17025:2017 Clause 7.7, ensuring metrological integrity prior to sample analysis.

Applications

• Field-based water quality assessment in rivers, lakes, and groundwater monitoring wells
• In-process pH control during chemical dosing in municipal wastewater treatment (e.g., coagulation, disinfection, denitrification)
• Boiler water and steam condensate monitoring in thermal power generation facilities
• Environmental compliance sampling per local discharge permits (e.g., EPA NPDES, China MEP Order No. 39)
• Education and vocational training labs requiring robust, entry-level electrochemical instrumentation
• Food and beverage sanitation validation where rapid handheld verification is required between CIP cycles

FAQ

What calibration buffers are supported by the SX711?

The meter automatically identifies 13 standard buffers across three regional sets: DIN/ISO (pH 1.68, 4.01, 6.86, 9.18, 12.45), NIST (pH 1.66, 4.01, 6.86, 9.18, 12.45), and China National Standards (pH 4.00, 6.86, 9.18).
Can the SX711 measure pH in low-conductivity water such as deionized or distilled water?

Yes—the dedicated “High-Purity Water” mode applies algorithmic correction for liquid-junction potential errors common below 50 µS/cm conductivity.
Is the included electrode suitable for continuous immersion?

The 201T-S tri-combination electrode is rated for intermittent field use; for extended submersion (>8 h), periodic cleaning and storage in 3 mol/L KCl solution is recommended to maintain junction stability.
Does the SX711 support GLP-compliant recordkeeping?

It stores 200 measurement events with full contextual metadata (ID, value, unit, temperature), satisfying minimum GLP data retention expectations—though external documentation of calibration dates and operator IDs remains the user’s responsibility.
What is the battery life under typical usage?

With two AA alkaline cells, operational life exceeds 200 hours under normal field conditions (10 min/day usage, auto-off enabled).