OHAUS ST5000pH Benchtop Multi-Parameter Electrochemical Meter

Overview

The OHAUS ST5000pH is a high-precision benchtop electrochemical meter engineered for rigorous laboratory environments requiring trace-level pH measurement integrity. Designed in accordance with fundamental potentiometric principles—measuring the electromotive force (EMF) generated across a glass electrode–reference electrode pair—the ST5000pH delivers metrological-grade performance for applications demanding reproducibility at the 0.001 pH unit level. Its triple-parameter architecture simultaneously acquires and displays pH, redox potential (mV), and temperature, with automatic temperature compensation (ATC) enabled via integrated Pt1000 or NTC sensors. The instrument’s core electronics feature low-noise analog front-end circuitry, 24-bit ADC resolution, and real-time drift correction algorithms—critical for minimizing electrode polarization artifacts during extended measurements. As a direct-manufactured system built in Jiangsu, China, the ST5000pH adheres to OHAUS’ global design heritage while incorporating localized calibration standard support essential for regulatory alignment in pharmaceutical QC, academic research, and environmental testing laboratories.

Key Features

• Full-color 7-inch capacitive touchscreen interface with intuitive icon-driven navigation and multi-language support (English, Chinese, Spanish, German)
• Triple-parameter simultaneous readout: pH, mV, and temperature—with user-selectable resolution modes (e.g., 0.001 pH / 0.01 mV / 0.1 °C)
• Advanced calibration management supporting up to 5-point pH calibration with slope/offset diagnostics and real-time electrode health monitoring
• Eight built-in calibration solution profiles compliant with national and international standards: GB/T 604–2002 (China), ASTM D1293, DIN 19263, ISO 10523, USP , and Merck Titrisol® reference sets
• Rugged ABS housing with IP54-rated enclosure, integrated electrode holder, and USB-C data export port compatible with U disk storage
• GLP-compliant audit trail functionality—including operator ID tagging, calibration event logging, and timestamped measurement records

Sample Compatibility & Compliance

The ST5000pH supports universal electrode compatibility with standard BNC and mini-DIN connectors, enabling seamless integration with OHAUS-recommended combination electrodes (e.g., ST310, ST320) as well as third-party pH/mV probes meeting IEC 60068-2-30 humidity and IEC 61000-4-3 EMC specifications. It meets key regulatory prerequisites for quality-controlled environments: full traceability per ISO/IEC 17025 requirements, compliance with FDA 21 CFR Part 11 for electronic records (when paired with OHAUS LabX™ Lite software), and conformance to EN 61326-1 for electromagnetic immunity. Temperature probe inputs accept both RTD (Pt1000) and thermistor (NTC 30kΩ) configurations, ensuring accurate ATC across aqueous, non-aqueous, and high-viscosity samples—validated per ASTM E2072 for pH meter performance verification.

Software & Data Management

Data handling is optimized for laboratory workflow efficiency. Internal memory stores up to 2,000 measurement records with metadata (date/time, operator ID, calibration status, electrode serial number). Raw data exports in CSV format via USB mass storage mode are fully compatible with LIMS platforms and statistical analysis tools (e.g., JMP, Minitab). Optional connectivity to OHAUS LabX™ Lite enables centralized instrument configuration, remote calibration validation, and automated report generation—including PDF certificates with digital signatures. All data transfers comply with IEEE 802.3 Ethernet protocols when used with optional LAN adapter, and audit logs retain immutable entries for ≥18 months—satisfying GLP/GMP documentation retention mandates.

Applications

The ST5000pH serves critical roles in regulated and research-intensive settings: routine pH verification of buffer solutions in pharmaceutical formulation labs (per USP ); titration endpoint detection in food safety testing (AOAC 984.27); long-term stability monitoring of fermentation broths in bioprocessing; corrosion potential assessment in industrial cooling water systems (ASTM D3733); and teaching electrochemistry fundamentals in university laboratories where Nernst equation validation requires sub-millipH resolution. Its extended pH range (−2.000 to 20.000) accommodates highly acidic pickling baths and concentrated alkaline scrubber solutions—environments where conventional meters exhibit electrode saturation or junction clogging.

FAQ

Does the ST5000pH support automatic electrode recognition?
Yes—when used with OHAUS SmartElectrode™ series probes (e.g., ST310-Smart), the meter auto-detects sensor type, serial number, and calibration history.
Can calibration data be exported separately from measurement records?
Yes—calibration logs are stored independently and exportable as standalone CSV files with full traceability metadata.
Is the instrument suitable for non-aqueous solvent measurements?
It supports non-aqueous pH measurement using appropriate electrodes and solvent-specific calibration buffers, though accuracy may vary depending on liquid junction potential effects.
What is the recommended recalibration frequency under GLP conditions?
Per ISO/IEC 17025:2017 Clause 7.7, recalibration is required before each analytical batch or at least every 24 hours—whichever occurs first—and after any maintenance or electrode replacement.
Does the ST5000pH meet FDA 21 CFR Part 11 requirements out-of-the-box?
Hardware-level compliance is inherent; full Part 11 enforcement (e.g., electronic signatures, role-based access control) requires LabX™ Lite software deployment and site-specific validation documentation.