YSI ProSolo Optical Dissolved Oxygen and Temperature Meter (4 m Cable)

Overview

The YSI ProSolo Optical Dissolved Oxygen and Temperature Meter is a field-deployable, fluorescence-based analytical instrument engineered for high-accuracy, non-consumptive measurement of dissolved oxygen (DO) and temperature in aquatic environments. Unlike electrochemical Clark-type sensors—which consume oxygen during measurement and require flow-dependent calibration—the ProSolo employs solid-state optical sensing via phase-fluorescence quenching. A blue LED excites a ruthenium-based luminophore immobilized on the sensor tip; molecular oxygen modulates the decay time of emitted red fluorescence, enabling precise, drift-resistant quantification without oxygen depletion or stirring artifacts. This principle delivers stable performance across static, low-flow, and turbulent water columns—from shallow wetlands to deep aquifers—while maintaining compliance with U.S. Environmental Protection Agency (EPA) Method 4500-O G for biochemical oxygen demand (BOD) determination and other regulatory water quality assessments.

Key Features

• Optical DO sensor with integrated temperature compensation: eliminates cross-sensitivity to hydrogen sulfide, chlorine, and other redox-active interferents common in wastewater and eutrophic systems.
• Replaceable threaded optical cap (≥2-year service life): modular design enables rapid field maintenance without recalibration; sensor body retains calibration coefficients in non-volatile memory.
• Ergonomic, IP67-rated housing with military-spec cable connector: validated for repeated 1.2-m drops onto concrete and continuous submersion at 1 m for 30 min—suitable for rugged field deployment in rain, mud, or saline splash zones.
• Color LCD with backlight and multi-language UI (including Simplified Chinese): supports operation under low-light conditions and accommodates international field teams.
• Smart probe recognition: host automatically detects connected sensor type and loads embedded calibration data—enabling seamless probe interchange between multiple ProSolo units without manual reconfiguration.
• USB-powered operation and charging: dual-mode power management allows real-time data logging while tethered to external 5 V power or battery-only autonomous use (up to 48 h per charge; 9 h recharge time).

Sample Compatibility & Compliance

The ProSolo is validated for use across freshwater, estuarine, marine, and wastewater matrices—including high-turbidity surface waters, hyporheic zone groundwater, aquaculture ponds, and activated sludge basins. Its optical architecture ensures minimal biofouling susceptibility and long-term signal stability under variable salinity (0–70 ppt) and pH (4–12). All factory calibrations are traceable to NIST-certified standards. The instrument meets ASTM D888–22 (Standard Test Methods for Dissolved Oxygen in Water), ISO 5815–1:2016 (Water quality — Determination of biochemical oxygen demand after n days — Part 1: Dilution and inoculation method), and supports GLP/GMP-compliant workflows through full audit-trail functionality: timestamped calibration logs (400 entries), user-defined site IDs (100), and data tags (100) are stored internally and exportable via USB mass storage mode.

Software & Data Management

Data acquisition and post-processing are supported by YSI’s KorDSS (Kor Data System Software), a Windows-based application enabling bidirectional communication, real-time telemetry visualization, and batch export to CSV, Excel, or GIS-ready formats. No proprietary drivers are required—KorDSS mounts the ProSolo as a standard USB mass storage device, permitting direct drag-and-drop backup to USB flash drives without PC connectivity. Internal memory stores >100,000 timestamped records (DO, temperature, depth if paired with optional pressure sensor, GPS coordinates if external module attached), each tagged with operator ID, location metadata, and QC flags. All calibration events—including zero-point, span, and two-point field calibrations—are logged with date/time, operator name, and reference standard values—fully satisfying FDA 21 CFR Part 11 requirements for electronic records and signatures when used in regulated environmental laboratories.

Applications

• Aquaculture monitoring: real-time DO profiling to optimize aeration schedules, prevent hypoxia-induced mortality, and validate feed conversion efficiency models.
• Regulatory ambient monitoring: EPA NPDES permit compliance, TMDL assessments, and watershed-scale DO saturation mapping in rivers, lakes, and tidal marshes.
• Wastewater treatment: process control of aerobic digesters, nitrification basins, and final effluent discharge verification per 40 CFR Part 136.
• Academic research: undergraduate hydrology labs, graduate limnology field studies, and long-term ecological research (LTER) network deployments requiring metrologically defensible DO time-series.
• Groundwater/surface water interaction studies: high-resolution vertical profiling in piezometers and nested wells using optional extended-length cables (up to 100 m).

FAQ

Does the ProSolo require membrane replacement or electrolyte refilling like traditional DO probes?
No—its optical sensor contains no membranes, electrolytes, or cathodes. Maintenance is limited to periodic optical cap replacement every 2+ years.
Can the same probe be used interchangeably between multiple ProSolo hosts?
Yes—the probe stores its unique calibration coefficients and serial number in onboard memory; detection and parameter loading occur automatically upon connection.
Is the instrument suitable for continuous unattended logging?
While designed primarily for spot sampling and profiling, it supports timed interval logging (1 s to 24 h intervals) with internal storage—though external power and secure mounting are recommended for extended deployments.
What validation documentation accompanies the instrument?
Each unit ships with a NIST-traceable calibration certificate, EPA method validation summary, and full ISO/IEC 17025-compliant test report from YSI’s accredited metrology lab.
How is temperature compensation handled during DO measurement?
A high-precision thermistor embedded adjacent to the optical sensor provides real-time thermal correction per the Stern–Volmer equation, eliminating manual input or lookup tables.