WTW OxiTop-IS6 Laboratory BOD Analyzer
| Brand | WTW |
|---|---|
| Origin | Germany |
| Model | OxiTop-IS6 |
| Instrument Type | Laboratory BOD Analyzer |
| Measurement Principle | Pressure Difference Method (Manometric) |
| Measurement Range | 2–4000 mg/L |
| Detection Limit | 2 mg/L |
| Accuracy | ±5% |
| Incubation Duration | 5-day standard test |
| Repeatability | ±3% |
| Operating Temperature | +5 to +50 °C |
| Display | Dual-digit 7-segment LED (10 mm), 00–50 range |
| Pressure Sensing Range | 500–1100 hPa |
| Accuracy of Pressure Reading | ±1 digit (±3.55 hPa) |
| Power Supply | 2×CR2430 lithium batteries (280 mAh total) |
| Max Current Draw | 25 mA (during display activation) |
| Safety Rating | Category III per IEC 61010-1 |
| Ingress Protection | IP54 per DIN 40050 |
| Dimensions | 69 mm H × 70 mm Ø |
| Compliance | DIN 38409-52 (BODₙ determination) |
Overview
The WTW OxiTop-IS6 is a fully automated, mercury-free laboratory BOD analyzer engineered for precise, compliant, and operator-safe biochemical oxygen demand measurement in accordance with DIN 38409-52 (BODn). Unlike conventional manometric systems relying on toxic mercury columns, the OxiTop-IS6 employs a solid-state pressure transducer integrated into a sealed, self-contained measuring head to detect oxygen consumption via real-time pressure differentials within closed BOD bottles. This principle eliminates vapor-phase mercury exposure risks while maintaining metrological traceability to standardized 5-day incubation protocols. The system is designed for routine environmental laboratories conducting regulatory water quality assessments—including municipal wastewater effluents, surface waters, industrial discharges, and treated drinking water sources—where reproducibility, audit readiness, and long-term operational reliability are critical.
Key Features
- Mercy-free operation: Eliminates all mercury-based components, complying with EU RoHS Directive 2011/65/EU and global occupational health standards for laboratory safety.
- Integrated pressure sensing: High-stability piezoresistive transducer calibrated against reference pressure standards; maintains accuracy across ambient barometric fluctuations (500–1100 hPa).
- Autonomous 5-day measurement cycle: Fully unattended operation with daily BOD value logging and automatic endpoint calculation at 120 hours.
- Robust mechanical architecture: IP54-rated housing ensures resistance to dust ingress and incidental splashes during handling in shared lab environments.
- Low-power design: Dual CR2430 lithium batteries support ≥60 days of typical use (including 5-day tests and standby); no external power supply required during incubation.
- Scalable configuration: The IS6 variant supports up to six parallel BOD bottles; modular expansion kits enable seamless upgrade to 12-bottle or remote-monitoring configurations.
Sample Compatibility & Compliance
The OxiTop-IS6 accommodates standard 250 mL or 300 mL BOD bottles with integrated septum-sealed caps. It accepts both seeded and unseeded samples per ISO 5815-1:2019 and APHA Standard Methods 5210B. All measurements conform to DIN 38409-52 for BODn, ensuring equivalence with traditional dilution methods. Data integrity meets GLP requirements through time-stamped, non-editable storage of raw pressure readings and derived BOD values. While not inherently 21 CFR Part 11-compliant (as it lacks electronic signature capability), the system supports export of CSV-formatted logs for integration into validated LIMS platforms with full audit trail functionality.
Software & Data Management
The OxiTop-IS6 operates as a standalone instrument with embedded firmware—no PC connection required for basic operation. Daily BOD results (mg/L) and corresponding pressure differentials (hPa) are stored internally with date/time stamps. Data retrieval occurs via IR interface using optional WTW LabX software or manual readout from the dual-digit LED display. Exported datasets include incubation start/end timestamps, temperature compensation flags (if used with optional temperature probe), and calculated BOD5 values per DIN equation. For laboratories requiring digital archiving, LabX enables batch reporting, trend analysis, and PDF certificate generation aligned with ISO/IEC 17025 documentation requirements.
Applications
- Regulatory compliance testing for municipal wastewater treatment plants (WWTPs) under national discharge permits.
- Environmental impact assessment (EIA) of industrial effluents prior to release into receiving waters.
- Research-grade evaluation of biodegradability kinetics for novel organic compounds or wastewater treatment additives.
- Quality assurance in drinking water production facilities monitoring post-filtration biostability.
- Educational laboratories teaching standardized BOD methodology without hazardous material handling protocols.
FAQ
Does the OxiTop-IS6 require calibration before each use?
No. The pressure sensor is factory-calibrated and retains stability over its service life; periodic verification against a certified pressure standard is recommended annually.
Can the system be used for BOD measurements shorter or longer than 5 days?
Yes. While optimized for the standard 5-day incubation (BOD5), the device records pressure data hourly, enabling retrospective calculation of BODn for n = 1–28 days if incubation duration is extended.
Is temperature control built into the OxiTop-IS6?
No. The instrument itself does not regulate temperature; it must be placed inside a certified BOD incubator maintained at 20.0 ± 1.0 °C per DIN 38409-52 and ISO 5815-1.
How is sample dilution handled in the OxiTop workflow?
Dilution is performed manually prior to bottling, following standard APHA procedures; the OxiTop measures only the oxygen depletion in the prepared sample vial and applies user-input dilution factors during final BOD calculation.
What happens if battery voltage drops during a 5-day test?
The device enters low-power sleep mode between readings; internal diagnostics prevent data loss, and all logged values remain intact until retrieval—even if batteries deplete completely after test completion.
