METTLER TOLEDO SevenGo Pro™ Dissolved Oxygen Meter – SG6

Overview

The METTLER TOLEDO SevenGo Pro™ Dissolved Oxygen Meter – SG6 is a field-deployable, high-precision electrochemical instrument engineered for reliable and traceable dissolved oxygen (DO) measurement in environmental water monitoring applications. It operates on the polarographic principle using a Clark-type membrane-covered amperometric sensor—specifically the InLab® 605 series electrode—to quantify oxygen partial pressure in aqueous samples. The integrated barometric pressure sensor enables real-time compensation for altitude- and weather-induced atmospheric pressure variations, ensuring consistent calibration integrity across diverse sampling locations. Designed for compliance with international water quality standards—including ISO 5814, ASTM D888, and EN 25814—the SG6 delivers repeatable, temperature-compensated DO values in both % saturation and mg/L units, supporting regulatory reporting requirements in wastewater treatment, surface water assessment, aquaculture, and ecological field studies.

Key Features

• IP67-rated rugged housing for dust and immersion resistance (up to 1 m for 30 min), enabling operation in rain, mud, or splashed laboratory environments
• Integrated digital barometer with automatic or manual pressure compensation—eliminating manual correction steps during field calibration
• InLab® 605 DO electrode with fast response time (< 30 s to 90 %), low drift (< 0.1 mg/L/h), and built-in temperature sensor for simultaneous dual-parameter measurement
• Backlit custom LCD display with adjustable contrast, optimized for readability under direct sunlight or low-light conditions
• GLP-compliant data management: stores up to 200 measurement records with timestamp, electrode ID, calibration history, temperature, pressure, and operator ID
• Infrared (IR) wireless interface for secure, cable-free data export to printers or PCs; RS232/USB connectivity supported via optional IR-to-serial adapter
• Extended battery life (up to 10,000 measurements per set of AA alkaline cells) and support for rechargeable NiMH batteries

Sample Compatibility & Compliance

The SG6 is validated for use with freshwater, seawater (with salinity compensation), wastewater effluents, and process streams across pH 0–14 and conductivity up to 200 mS/cm. Its InLab® 605 electrode employs a gas-permeable Teflon membrane and electrolyte-filled cathode/anode configuration, minimizing fouling in turbid or organic-rich matrices. All stored data meet GLP documentation requirements, including audit-trail-capable metadata (e.g., calibration date/time, standard used, slope/mV offset). While not inherently 21 CFR Part 11 compliant, the instrument supports integration into validated workflows when paired with METTLER TOLEDO LabX® software (via IR-to-PC bridge) for electronic signature, user access control, and electronic record retention.

Software & Data Management

Data captured by the SG6 are structured in a vendor-neutral format compatible with common spreadsheet and LIMS platforms. Each GLP record includes: measurement value (% sat or mg/L), temperature (°C), atmospheric pressure (mbar), electrode serial number, calibration status, and full timestamp (YYYY-MM-DD HH:MM:SS). Export occurs via infrared transmission using METTLER TOLEDO’s proprietary IR protocol—no drivers required for basic printing. For advanced traceability, optional LabX Lite software enables automated report generation, trend analysis, and deviation flagging against predefined limits. All calibration events are logged with reference standard details (e.g., Winkler titration result or zero-oxygen solution batch number), satisfying ISO/IEC 17025 clause 7.7 and EPA Method 360.1 documentation expectations.

Applications

• Regulatory compliance monitoring of receiving waters per EPA NPDES permits and EU Water Framework Directive (WFD) criteria
• Biochemical oxygen demand (BOD₅) incubation tracking in wastewater treatment plants
• Aquaculture pond management—real-time DO profiling to prevent hypoxia stress in finfish and shellfish operations
• Stream health assessment in watershed restoration projects, including diurnal DO cycling analysis
• Field validation of online DO sensors deployed in municipal water distribution networks
• Educational laboratory instruction on aquatic chemistry principles and sensor metrology

FAQ

Does the SG6 support automatic temperature compensation during DO measurement?
Yes—the InLab® 605 electrode incorporates a built-in Pt1000 temperature sensor, enabling continuous, real-time temperature correction per the Stern–Volmer equation without manual input.
Can the SG6 be calibrated at altitude above 2000 m?
Yes—its internal barometer (500–1100 mbar range) automatically adjusts saturation calculations; no external pressure input is required for altitudes up to ~3000 m ASL.
Is the InLab® 605 electrode suitable for seawater measurements?
Yes—when configured with salinity input (manually entered or via optional conductivity module), the SG6 applies the Garcia & Gordon (1992) solubility model for accurate marine DO reporting.
How is GLP compliance enforced in the data storage system?
Each stored record contains immutable metadata fields (date/time stamp, electrode ID, calibration parameters); deletion or overwriting of historical entries is physically disabled in firmware.
What accessories are required for full EPA Method 360.1 compliance?
The SG6-FK2 or SG6-FK10 kits include certified calibration standards, traceable certificates, and field-ready transport—meeting minimum equipment requirements for Method 360.1 field verification when used with documented SOPs.