Chemtron Lab 745 Dissolved Oxygen Meter
| Brand | JULABO-Chemtron |
|---|---|
| Origin | Italy |
| Manufacturer Type | Authorized Distributor |
| Origin Category | Imported |
| Model | Lab 745 |
| Price | Upon Request |
| Measurement Range | 0–200 % saturation / 0–20 mg/L |
| Temperature Range | −10 to 100 °C |
| Resolution | 1 % / 0.01 mg/L / 0.1 °C |
| Temperature Compensation | Automatic NTC 30 kΩ or fixed-value compensation |
| Accuracy | ±1 digit, ±0.5 % of reading, ±0.1 °C (5–50 °C) |
| Electrode Interface | 8-pin polarographic or galvanic probe connector |
| Communication Interface | 4-pin USB |
| Calibration | Single-point, temperature-compensated |
| Data Logging Capacity | 4000 records (timestamp, DO value [mg/L and %], temperature) |
Overview
The Chemtron Lab 745 Dissolved Oxygen Meter is a precision electrochemical instrument engineered for reliable, repeatable measurement of dissolved oxygen (DO) concentration in aqueous solutions across laboratory, quality control, and environmental monitoring applications. It operates on the principle of amperometric detection—either via Clark-type polarographic or galvanic membrane-covered sensors—where oxygen diffuses through a selective membrane and undergoes reduction at a cathode, generating a current proportional to partial pressure. The Lab 745 integrates automatic temperature compensation using a built-in NTC 30 kΩ thermistor, ensuring accurate conversion from partial pressure to concentration units (mg/L) and saturation percentage (% air saturation) across a broad thermal range (−10 to 100 °C). Its dual-range display supports simultaneous readout in both conventional units—enabling direct comparison with regulatory benchmarks such as those defined in ISO 5814, ASTM D888, and USP for pharmaceutical water systems.
Key Features
- High-resolution dual-mode display: 0.01 mg/L and 1 % saturation resolution ensures sensitivity for low-oxygen environments (e.g., anaerobic bioreactors) and high-precision calibration verification.
- Wide operational temperature range (−10 to 100 °C) with ±0.1 °C accuracy between 5 and 50 °C—critical for process validation in sterilization cycles or fermentation profiling.
- Intelligent single-point calibration routine with user-defined temperature compensation, eliminating need for saturated air/water standards at multiple temperatures.
- Robust 8-pole electrode interface supporting interchangeable polarographic and galvanic DO probes—compatible with Chemtron’s full sensor portfolio including ruggedized industrial-grade membranes.
- Built-in 4-pin USB interface enables direct connection to Windows-based PCs for real-time data streaming and firmware updates without external adapters.
- Non-volatile memory stores up to 4,000 timestamped records—including date, time, DO (mg/L and %), and temperature—structured for traceability under GLP and GMP audit requirements.
Sample Compatibility & Compliance
The Lab 745 is validated for use with deionized water, buffer solutions, culture media, wastewater effluents, and purified water (PW) and water-for-injection (WFI) systems per EU Annex 1 and FDA guidance. Its sensor interface meets IEC 61000-6-2/6-3 immunity and emission standards. The meter’s measurement algorithm adheres to ISO 5814:2012 (electrochemical determination of dissolved oxygen) and supports compliance with pharmacopeial methods requiring documented temperature compensation and calibration traceability. All stored data include embedded timestamps compliant with FDA 21 CFR Part 11 requirements when used with validated software and access-controlled user accounts.
Software & Data Management
Data export is supported via native USB HID protocol—no proprietary drivers required. Logged datasets are exported in CSV format, preserving all metadata (UTC timestamp, sensor ID if encoded, operator ID field, and environmental context). Optional Chemtron DataBridge™ software (v3.2+) provides automated report generation, trend visualization, alarm threshold configuration, and electronic signature support for 21 CFR Part 11 workflows. Audit trails record all calibration events, parameter changes, and data exports with immutable timestamps and user attribution.
Applications
- Pharmaceutical water system validation and routine monitoring (PW, WFI, pure steam condensate).
- Bioreactor and fermenter DO control loop verification during upstream processing.
- Environmental lab analysis of surface water, groundwater, and wastewater treatment streams per EPA Method 360.1.
- Academic research in aquatic ecology, corrosion science, and microbial respiration kinetics.
- Food & beverage QC for modified atmosphere packaging (MAP) headspace analysis and process water hygiene assessment.
FAQ
Does the Lab 745 support two-point calibration?
No—it implements a single-point, temperature-compensated calibration protocol optimized for stability and reproducibility in regulated environments where multi-point drift correction is discouraged per ISO/IEC 17025 clause 7.7.
Can it be used with non-Chemtron DO electrodes?
Yes, provided the electrode conforms to the standardized 8-pin DIN 19262 pinout and outputs a stable, linear nA-level signal compatible with amperometric transimpedance amplification.
Is the internal memory battery-backed?
Yes—the SRAM retains logged data and configuration settings for ≥10 years without power, meeting IEC 60747-17 retention specifications.
What is the recommended recalibration interval?
Per ISO/IEC 17025, recalibration is required before each analytical series or at least every 24 hours for continuous operation; frequency may be extended with documented performance verification per internal SOP.
Does it meet IP rating requirements for wet-lab use?
The front panel meets IP54 (dust-protected, splash-resistant); optional Chemtron LabShield™ enclosure extends protection to IP65 for benchtop deployment near autoclaves or wash stations.
