ChemTron Lab 955 Benchtop Conductivity and pH Meter
| Brand | ChemTron |
|---|---|
| Origin | Germany |
| Model | Lab 955 |
| Instrument Type | Benchtop |
| Parameter Types | Dual (pH & Conductivity) |
| pH Range | –2.0 to 20.0 (±0.1), –2.00 to 20.00 (±0.01), –2.000 to 19.999 (±0.005) |
| mV Range | ±1200.0 mV (±0.3 mV), ±2000 mV (±1 mV) |
| Conductivity Range | 0.00–1000 mS/cm (±0.5% of reading) |
| Resistivity | 0.00–99.9 MΩ·cm |
| Salinity | 0.0–70.0 (IOT standard) |
| TDS | 1–999 mg/L |
| Temperature Range | –5.0 to +105.0 °C (±0.1 °C) |
| Temperature Compensation | None, Nonlinear (nlF), Linear (0.000–3.000 %/K), Auto or Manual |
| Cell Constants | Fixed K = 0.01 cm⁻¹ |
| Calibration Range | 0.450–0.500 cm⁻¹, 0.800–0.880 cm⁻¹ |
| Memory Capacity | 500 / 5000 readings* |
| Calibration Points | 1-point pH |
| GLP/AQS Compliance | Yes |
| CMC Function | Yes |
| Interface | Mini USB-B |
| Electrode Connector | DIN pH-2.0 |
Overview
The ChemTron Lab 955 Benchtop Conductivity and pH Meter is a dual-parameter electrochemical analyzer engineered for precision, repeatability, and regulatory compliance in quality control and R&D laboratories. Built on a robust German-designed platform, it employs potentiometric measurement for pH and four-electrode (or two-electrode) AC conductometric principles for conductivity—minimizing polarization errors and enabling stable readings across wide dynamic ranges. Its architecture supports simultaneous real-time acquisition of pH, mV, conductivity, resistivity, salinity, TDS, and temperature, with automatic temperature compensation (ATC) using either linear, nonlinear (nlF), or user-defined β-coefficient models. Designed explicitly for environments governed by ISO/IEC 17025, USP , ASTM D1125, and pharmacopeial water quality testing protocols (e.g., Purified Water, Water for Injection), the Lab 955 delivers traceable, auditable measurements aligned with GLP and AQS (Analytical Quality System) frameworks.
Key Features
- High-resolution graphical LCD display with intuitive icon-driven interface and tactile keyboard feedback—optimized for gloved operation and prolonged visual clarity under laboratory lighting.
- Active auto-read functionality ensures measurement stabilization detection before data capture, eliminating operator-dependent endpoint judgment and enhancing inter-user reproducibility.
- Dual-parameter capability with independent calibration routines for pH and conductivity, each supporting single-point calibration with full audit trail logging including date, time, electrode ID, buffer/solution used, slope, offset, and temperature.
- Configurable cell constant management: supports fixed-cell (K = 0.01 cm⁻¹) and adjustable cells (K = 0.090–2.500 cm⁻¹), with built-in validation of calibration factor against certified reference standards (e.g., KCl solutions per ISO 7888).
- Comprehensive memory system storing up to 500 standard or 5000 extended records—including raw sensor values, compensated results, user annotations, and GLP metadata—accessible via Mini USB-B for export to LIMS or Excel-compatible CSV files.
- CMC (Conductivity Measurement Control) function enables automated verification of electrode performance prior to measurement, flagging drift or contamination based on pre-set acceptance thresholds.
Sample Compatibility & Compliance
The Lab 955 accommodates aqueous samples ranging from ultrapure water (resistivity >10 MΩ·cm) to aggressive industrial process streams (conductivity up to 1000 mS/cm). It is compatible with all standard DIN pH electrodes (e.g., gel-filled, refillable, double-junction) and conductivity cells conforming to IEC 60746-3, including platinized stainless steel, graphite, and titanium sensor configurations. The instrument meets CE marking requirements and fulfills essential criteria for FDA 21 CFR Part 11 readiness when paired with validated software and procedural controls—supporting electronic signatures, audit trails, and data integrity safeguards required in pharmaceutical manufacturing (GMP Annex 11) and clinical chemistry labs.
Software & Data Management
Data transfer occurs exclusively via Mini USB-B port using vendor-neutral CSV format—ensuring seamless integration with third-party analysis tools, ELN platforms, and enterprise LIMS without proprietary drivers. All stored entries include embedded timestamps, operator IDs (assignable via keypad), calibration history, and environmental context (ambient temperature, atmospheric pressure if externally linked). GLP-compliant reporting includes full traceability of measurement conditions, sensor status flags, and deviation alerts—enabling full reconstructability during internal audits or regulatory inspections (e.g., EMA, MHRA, PMDA).
Applications
- Pharmaceutical QC: USP purified water and WFI conductivity verification; buffer preparation validation; cleaning solution monitoring.
- Chemical manufacturing: Acid/base concentration profiling; electrolyte stability assessment in battery electrolytes; catalyst slurry conductivity screening.
- Environmental testing: Surface water salinity and TDS quantification per EPA Method 120.1; wastewater effluent compliance checks (ISO 10523, ISO 7888).
- Food & beverage: Brine strength control in canning operations; dairy product pH consistency; brewing wort conductivity monitoring.
- Academic research: Kinetic studies involving ion generation/consumption; membrane transport characterization; corrosion inhibitor efficacy evaluation.
FAQ
Does the Lab 955 support multi-point pH calibration?
No—it implements single-point pH calibration optimized for routine QC workflows where standardized buffers (e.g., pH 4.01, 7.00, 10.01) are verified daily against NIST-traceable references. Slope and asymmetry potential are logged for trend analysis.
Can conductivity be measured at non-standard temperatures without compensation?
Yes—the instrument allows manual temperature entry or disables compensation entirely, permitting raw uncorrected σ-values for research applications requiring absolute conductivity at defined thermal states.
Is the Mini USB-B interface capable of real-time data streaming?
No—data transfer is batch-oriented post-measurement. Real-time serial output is not supported; continuous logging requires external DAQ hardware interfaced via analog outputs (if equipped).
What documentation is provided for IQ/OQ validation?
ChemTron supplies a comprehensive Validation Support Package including URS template, FAT/SAT checklists, calibration certificate templates, and traceable test protocols aligned with ASTM E2500 and GAMP5 guidelines.
How is electrode drift managed between calibrations?
The CMC function performs periodic impedance-based diagnostics and compares current cell constant against baseline; deviations exceeding ±2% trigger advisory alerts—supporting proactive maintenance scheduling per preventive maintenance SOPs.
