YSI DO200 Dissolved Oxygen and Temperature Meter

Overview

The YSI DO200 Dissolved Oxygen and Temperature Meter is a field-deployable, handheld instrument engineered for reliable, real-time measurement of dissolved oxygen (DO) concentration and temperature in freshwater, estuarine, and coastal environments. It employs steady-state polarographic detection with a polyethylene (PE) membrane electrode—a well-established electrochemical method compliant with ASTM D888 and ISO 5814 standards for dissolved oxygen determination. The integrated thermistor sensor (10 kΩ at 25 °C) provides simultaneous temperature measurement, enabling automatic temperature compensation of DO readings—an essential function for maintaining accuracy across variable thermal conditions. Designed for environmental monitoring professionals, wastewater operators, and academic field researchers, the DO200 delivers laboratory-grade data integrity in a rugged, portable form factor without requiring external power sources or complex calibration routines.

Key Features

• Rugged IP67-rated housing ensures full protection against dust ingress and immersion in water up to 1 m for 30 minutes—validated per IEC 60529.
• Stainless-steel probe body with overmolded polymer protective sleeve enhances mechanical durability and improves submersion stability during vertical profiling.
• Integrated stress-relief connector at the probe-cable junction mitigates cable fatigue under repeated flexing, extending service life in high-frequency field deployments.
• Low-stirring-dependency PE membrane technology reduces sensitivity to flow velocity variations—critical for accurate DO measurements in low-turbulence or stagnant water bodies.
• Simultaneous dual-parameter display: DO in both % air saturation and mg/L units, alongside temperature in °C, with user-selectable unit switching.
• Onboard automatic temperature compensation (ATC), plus manual input fields for salinity (0–50 ppt) and barometric pressure (600–1100 hPa), supporting site-specific correction per Winkler-derived reference methodologies.
• Battery status indicator with low-power warning ensures uninterrupted operation during extended sampling campaigns; powered by standard AA alkaline batteries (no proprietary battery required).

Sample Compatibility & Compliance

The YSI DO200 is validated for use with natural waters including rivers, lakes, reservoirs, wetlands, aquaculture ponds, and municipal effluent streams. Its polarographic sensor design conforms to the operational principles outlined in EPA Method 360.1 and APHA Standard Method 4500-O G. While not certified for GLP or 21 CFR Part 11 compliance out-of-the-box (as it lacks audit-trail logging), its measurement traceability aligns with ISO/IEC 17025 requirements when used within a documented quality system—including routine verification using saturated air and zero-oxygen (sodium sulfite) standards. Saltwater applications require manual salinity compensation; no built-in conductivity sensor is included.

Software & Data Management

The DO200 operates as a standalone field instrument with no embedded data logging or Bluetooth/Wi-Fi connectivity. All measurements are displayed in real time and intended for manual transcription or integration into external field notebooks and LIMS workflows. For users requiring digital data capture, YSI recommends pairing the DO200 with compatible third-party mobile apps via serial-to-Bluetooth adapters (e.g., Bt-110), though such configurations fall outside factory validation scope. Calibration records—including date, standard values, and slope/membrane response verification—must be maintained externally per ISO 17025 Clause 7.7 and US EPA QA/G-5 guidance.

Applications

• Regulatory ambient water quality monitoring per Clean Water Act Section 305(b) reporting protocols.
• Wastewater treatment plant process control—especially aeration basin optimization and final effluent compliance verification.
• Aquatic ecosystem health assessment, including hypolimnetic oxygen depletion tracking in stratified lakes.
• Educational field laboratories where robustness, intuitive interface, and single-hand operation support student-led sampling.
• Pre-screening prior to lab-based BOD₅ analysis, ensuring representative DO baseline establishment.
• Stormwater outfall characterization under varying tidal and rainfall conditions.

FAQ

Does the DO200 support automatic barometric pressure compensation?
No. Barometric pressure must be manually entered prior to measurement using the front-panel keypad.
Can the instrument store calibration history or measurement data?
No. The DO200 has no internal memory or data logging capability.
What membrane and electrolyte kit is compatible with the DO200 probe?
The YSI 5908 Membrane Kit (6 × 1.25 mL PE membranes + electrolyte solution) is the designated replacement set.
Is the probe suitable for long-term submerged deployment?
It is designed for spot-check and grab sampling—not continuous immersion. Extended submersion may accelerate membrane degradation and electrolyte depletion.
How often should the PE membrane be replaced?
YSI recommends membrane replacement every 2–4 weeks under regular field use, or immediately after exposure to oils, surfactants, or heavy biofouling.