OHAUS AQUASEARCHER™ AB41PH Benchtop pH/ORP/Temperature Meter
| Brand | OHAUS |
|---|---|
| Origin | Jiangsu, China |
| Manufacturer Type | Direct Manufacturer |
| Origin Category | Domestic (China) |
| Model | AB41PH-B |
| Instrument Type | Benchtop |
| Parameter Capability | Single-Parameter (pH), Dual-Mode (pH/mV/ORP) |
| Measurement Range | 0.00–14.00 pH |
| Resolution | 0.01 pH |
| Accuracy | ±0.002 pH |
| Calibration Solutions | China-Specific Buffer Set |
| Temperature Range | 0–100 °C |
| Temperature Resolution | 0.1 °C |
| Temperature Accuracy | ±0.3 °C |
| mV Range | −1999–+1999 mV |
| mV Resolution | 1 mV |
| mV Accuracy | ±0.3 mV |
| Display | 6.5-inch capacitive touchscreen LCD (segment + dot-matrix, backlit) |
| Data Storage | 1000 readings |
| Calibration Records | 10 most recent |
| GLP/GMP Compliance | Real-time clock, audit-ready data export via RS232/USB |
| Operating Environment | 5–40 °C, ≤80% RH (non-condensing) |
| Dimensions (H×L×W) | 51 × 210 × 142 mm |
| Net Weight | 0.5 kg |
| Housing Material | ABS |
| Integrated Features | Built-in magnetic stirrer, independent electrode stand, i-Steward intelligent measurement algorithm, three reading modes (stable, continuous, timed), calibration expiry alert, password-protected settings |
Overview
The OHAUS AQUASEARCHER™ AB41PH Benchtop pH/ORP/Temperature Meter is a rigorously engineered electrochemical analyzer designed for routine and regulated laboratory environments where reproducibility, traceability, and operational efficiency are critical. It operates on the fundamental principle of potentiometric measurement: pH is determined by measuring the potential difference between a pH-sensitive glass electrode and a stable reference electrode immersed in an aqueous sample, referenced against standardized buffer solutions. ORP (oxidation-reduction potential) is measured using the same electrode pair without pH compensation, reporting absolute redox potential in millivolts relative to the Standard Hydrogen Electrode (SHE). Temperature is concurrently measured via integrated Pt1000 or NTC thermistor circuitry (electrode-independent) to enable automatic temperature compensation (ATC) during pH and ORP readings. The AB41PH is not a portable field device but a fixed-position bench instrument optimized for controlled lab workflows—particularly in QC labs, academic teaching facilities, water treatment monitoring, and pharmaceutical stability testing where ISO/IEC 17025-aligned documentation and GLP-compliant recordkeeping are required.
Key Features
- i-Steward intelligent measurement algorithm ensures consistent endpoint detection across variable sample matrices, minimizing operator-dependent interpretation error and enhancing inter-user reproducibility.
- 6.5-inch capacitive touchscreen display combines segmented numeric fields with dot-matrix graphical elements for intuitive navigation—supporting gesture-based menu traversal, real-time trend visualization, and multi-language UI (English, Chinese, Spanish preloaded).
- Integrated magnetic stirrer with speed control (0–1200 rpm) and programmable stirring delay enables automated homogenization prior to measurement, reducing manual intervention and improving repeatability in viscous or heterogeneous samples.
- Three configurable reading modes: Stable Mode (auto-hold at defined stability threshold), Continuous Mode (real-time streaming), and Timed Mode (user-defined interval logging)—each supporting configurable auto-save triggers.
- Comprehensive GLP/GMP functionality: real-time clock (RTC) stamped data export, calibration expiry alerts, password-protected configuration lockout (admin/user levels), and full audit trail of all calibrations (date/time, buffer IDs, slope/mV offset, temperature).
- Robust ABS housing with IP20-rated enclosure meets IEC 61010-1 safety standards for laboratory electrical equipment; includes dedicated electrode holder, RS232 and USB-B ports for direct connection to LIMS or PC-based data acquisition software.
Sample Compatibility & Compliance
The AB41PH is validated for use with standard combination pH electrodes (BNC connector, 3.5 mm pin), including double-junction, gel-filled, and refillable designs compatible with aqueous, buffered, low-ionic-strength, and mildly aggressive chemical matrices (e.g., dilute acids/bases, saline solutions, tap water, wastewater effluents). It does not support non-aqueous or high-viscosity organic solvents without specialized electrodes. Calibration conforms to ASTM D1293 (pH of water), ISO 7888 (water quality), and USP (pH measurement in pharmaceutical preparations). All stored data include mandatory metadata: timestamp, operator ID (if entered), calibration status flag, temperature at time of measurement, and electrode identification (manual entry). The instrument’s firmware and data export structure comply with FDA 21 CFR Part 11 requirements when used with validated software and access controls.
Software & Data Management
Data output is structured as CSV-compatible ASCII files via RS232 or USB, containing columns for date/time (ISO 8601), pH/mV/°C values, measurement mode, calibration ID, and system status flags. No proprietary binary formats are used. The meter supports direct printing to ESC/POS-compatible thermal printers or forwarding to networked file servers via serial-to-Ethernet gateways. OHAUS provides free desktop software (AQUAConnect™ Lite) for data import, basic statistical analysis (mean, SD, CV%), report generation (PDF/Excel), and electronic signature capture—fully compatible with Windows 10/11 and macOS 12+. All exported files retain immutable RTC stamps and cannot be edited post-export, satisfying ALCOA+ principles (Attributable, Legible, Contemporaneous, Original, Accurate).
Applications
- Quality control of purified water and WFI (Water for Injection) per USP and EP 2.2.42 specifications.
- Environmental monitoring of surface water, groundwater, and wastewater treatment plant influent/effluent streams (EPA Method 150.1).
- Academic instruction in general chemistry and analytical labs—supporting student experiments on buffer capacity, titration curves, and acid dissociation constants.
- Food & beverage production: monitoring pH stability during fermentation, pasteurization validation, and shelf-life studies.
- Electroplating bath control: tracking acid concentration and redox state in nickel, copper, and chromium plating solutions.
- Research applications requiring traceable, timestamped pH kinetics under controlled stirring conditions (e.g., dissolution rate studies, enzyme activity assays).
FAQ
Does the AB41PH support automatic temperature compensation (ATC) without a built-in temperature probe?
Yes—the instrument accepts external ATC probes (e.g., OHAUS T-100 series) via the dedicated temperature input port. When no probe is connected, manual temperature entry is required for compensation.
Can calibration data be exported separately from measurement records?
Yes—calibration logs are stored independently and can be exported as a dedicated CSV file showing buffer IDs, measured mV/pH, slope (%), offset (mV), and acceptance criteria pass/fail status.
Is the touchscreen compatible with gloved operation in cleanroom environments?
The capacitive screen responds reliably to standard nitrile and latex gloves; however, for ISO Class 5+ environments, users should verify compatibility with their specific glove material and thickness during qualification.
What happens if power is interrupted during data logging?
All measurements up to the last confirmed write cycle are retained in non-volatile memory; unsaved data in RAM is lost, but the instrument resumes with intact calibration history and configuration upon reboot.
Does the AB41PH meet CE marking requirements for the European Economic Area?
Yes—it carries CE marking under the EMC Directive 2014/30/EU and Low Voltage Directive 2014/35/EU, with full Declaration of Conformity available upon request from OHAUS technical support.
