Digital Dissolved Oxygen and Temperature Meter DO5

Overview

The Digital Dissolved Oxygen and Temperature Meter DO5 is a portable, handheld electrochemical analyzer engineered for precise, field-deployable measurement of dissolved oxygen (DO) concentration and temperature in aqueous environmental and process water samples. It operates on the Clark-type polarographic principle, utilizing a membrane-covered amperometric sensor with a silver/silver chloride reference electrode and a gold or platinum cathode. Oxygen diffuses through a gas-permeable Teflon membrane into an electrolyte-filled chamber, where it undergoes reduction at the cathode surface—generating a current linearly proportional to the partial pressure of dissolved O₂. This analog signal is converted and processed digitally to yield calibrated readings in mg/L (ppm), % saturation, and °C/°F—each dynamically compensated for temperature, salinity, and barometric pressure per established Winkler-derived calibration conventions and ISO 5814:2012 guidelines.

Key Features

• Triple-parameter display: Simultaneous real-time readouts of DO in mg/L (ppm), % saturation, and temperature (°C/°F) on a high-contrast digital LCD
• Automatic temperature compensation (ATC) across 0–50 °C, eliminating manual correction errors during routine field use
• Manual salinity input (0.0–50.0 ppt) and atmospheric pressure adjustment (500–1499 mmHg) for accurate site-specific calibration
• Dedicated 100% air-saturation and zero-point calibration controls with offset-synchronized adjustment for rapid sensor validation
• Integrated electrode diagnostic function providing visual feedback on membrane integrity, electrolyte level, and cathode response stability
• Low-maintenance Clark-type sensor with gold cathode and electropolished silver anode; includes two spare membrane caps, electrolyte solution, and protective storage vial
• No warm-up time required; powered by four standard 1.5 V AAA batteries (included), delivering >700 hours of continuous operation

Sample Compatibility & Compliance

The DO5 is validated for use with freshwater, seawater, wastewater effluents, aquaculture systems, and laboratory-prepared standards. Its measurement range (0.00–20.00 mg/L DO; −5.0–150.0 °C) meets typical requirements for EPA Method 360.1, ASTM D888-22, and ISO 5814:2012. The instrument supports Good Laboratory Practice (GLP) workflows through traceable manual calibration logs and user-defined parameter entry (salinity, pressure). While not equipped with electronic audit trails or 21 CFR Part 11-compliant software, its calibration protocol aligns with QA/QC practices for non-regulated environmental monitoring and educational applications.

Software & Data Management

The DO5 operates as a standalone field instrument with no embedded data logging or PC connectivity. All measurements are displayed in real time only; no internal memory or USB/Bluetooth interface is provided. Users record results manually or integrate readings into external LIMS or spreadsheet-based reporting systems. Calibration parameters—including date, salinity value, barometric pressure, and span/zero points—are documented externally per institutional SOPs. Firmware is fixed and non-upgradable, ensuring operational consistency across deployments.

Applications

• Field-based ambient water quality assessment in rivers, lakes, estuaries, and groundwater monitoring wells
• Wastewater treatment plant process control: aeration basin optimization, activated sludge health evaluation, and effluent compliance verification
• Aquaculture and hatchery management: DO trending for fish health, feeding cycle correlation, and hypoxia risk mitigation
• Educational laboratories: undergraduate instruction in aquatic chemistry, environmental science, and sensor fundamentals
• Industrial cooling tower and boiler feedwater surveillance where oxygen corrosion potential must be quantified

FAQ

Does the DO5 support automatic barometric pressure compensation?
No—it requires manual entry of local atmospheric pressure (in mmHg) prior to calibration or measurement.
Can the sensor be used in high-salinity seawater without recalibration?
No—accurate DO reporting in saline media demands user-input salinity correction (0.0–50.0 ppt); failure to do so introduces systematic error per Henry’s law deviations.
Is the electrode compatible with replacement membranes from other manufacturers?
Only OEM-specified membrane caps and electrolyte solution are validated for performance and drift stability; third-party components may compromise accuracy and warranty coverage.
What is the recommended calibration frequency under routine field use?
Daily calibration is advised before first use each day; additional zero and span checks are recommended after exposure to extreme temperatures, biofouling conditions, or mechanical shock.
Does the instrument meet IP67 or equivalent ingress protection ratings?
The DO5 housing provides basic splash resistance but is not rated to IP67; it is not submersible and should be protected from prolonged moisture exposure or immersion.