ATAGO RX-5000i Automotive Urea Concentration Refractometer

Overview

The ATAGO RX-5000i Automotive Urea Concentration Refractometer is a precision benchtop optical instrument engineered for the accurate, traceable, and temperature-compensated measurement of urea concentration in aqueous solutions used in Selective Catalytic Reduction (SCR) systems. It operates on the principle of critical-angle refractometry: incident light undergoes total internal reflection at the prism–sample interface, with the resulting critical angle directly correlated to the solution’s refractive index (n_D). This index exhibits a well-characterized, monotonic relationship with urea mass fraction—particularly within the narrow operational window of 31.0–34.0% w/w—enabling high-fidelity quantification without chemical reagents or sample dilution. Designed specifically to meet the metrological requirements of GB 29518–2013 and aligned with ISO 22241–1:2019 specifications for diesel exhaust fluid (DEF), the RX-5000i delivers laboratory-grade repeatability in industrial QC, logistics verification, and field service environments.

Key Features

• Integrated Peltier temperature control system maintaining sample temperature at 20.0 °C ±0.1 °C—essential for compliance with GB 29518–2013 and ISO 22241 calibration protocols
• High-resolution Abbe-type optical path with automatic digital detection of the shadow line, eliminating parallax error and operator subjectivity
• Dual-scale display showing both refractive index (n_D) and urea concentration (% w/w) simultaneously, pre-calibrated against NIST-traceable urea reference standards
• Stainless steel sample stage and sapphire-coated measuring prism for long-term resistance to corrosion from ammonium carbamate decomposition byproducts
• Non-destructive, single-drop measurement requiring only 0.3 mL sample volume; typical measurement cycle completes in <3 seconds
• Compliant with IEC 61000-4 electromagnetic immunity standards and rated IP20 for controlled laboratory and workshop deployment

Sample Compatibility & Compliance

The RX-5000i is validated exclusively for aqueous urea solutions meeting ISO 22241–1 purity criteria (e.g., conductivity <125 µS/cm, alkalinity <0.2 mmol/L H⁺, biuret 5 µm. All factory calibrations are performed using certified reference materials traceable to NMIJ (National Metrology Institute of Japan) and documented per ISO/IEC 17025 requirements. The instrument satisfies metrological traceability chains required under China’s JJF 1301–2011 verification regulation for refractometers and supports audit-ready documentation for GLP and ISO 9001 quality management systems.

Software & Data Management

Data output is supported via RS-232 serial interface (standard) or optional USB-to-serial adapter. Raw measurements—including timestamp, temperature reading, n_D, % urea, and pass/fail status relative to 32.5 ±0.5% specification—are exportable as CSV files compatible with LIMS platforms. Firmware v3.2+ includes configurable data logging intervals (1–60 min), user-accessible calibration history with digital signatures, and audit trail functionality compliant with FDA 21 CFR Part 11 when deployed with validated PC-based acquisition software. No cloud connectivity or proprietary SaaS components are embedded.

Applications

• Final release testing of DEF batches in ISO 22241-certified manufacturing facilities
• In-transit verification at distribution terminals and fueling depots prior to retail dispensing
• On-site verification by OEM engine calibration labs during SCR system integration and durability validation
• Periodic concentration monitoring in fleet maintenance bays to prevent SCR catalyst poisoning or crystallization-induced dosing line blockage
• Root-cause analysis of urea decomposition events through trending of refractive index drift over time (indicative of hydrolysis or formaldehyde contamination)
• Supporting technical documentation for IATF 16949 process audits related to DEF handling and storage controls

FAQ

Does the RX-5000i require daily recalibration with standard solutions?
No—factory calibration remains stable for ≥6 months under routine use. A single-point verification using 32.5% w/w NIST-traceable urea standard is recommended before each shift or after ambient temperature excursions >5 °C.
Can it measure contaminated or aged DEF samples?
Yes, but results reflect total dissolved solids—not urea-specific content. Elevated readings may indicate hydrolysis products (e.g., ammonia, biuret) or particulate contamination; such deviations trigger investigation per ISO 22241–2 Annex C.
Is temperature compensation applied automatically during measurement?
Yes—the Peltier-controlled prism maintains constant 20.0 °C contact temperature regardless of ambient conditions, satisfying the fixed-temperature requirement of GB 29518–2013 Clause 6.2.
What maintenance is required beyond prism cleaning?
Annual verification of temperature sensor accuracy and optical alignment by an ATAGO-authorized service center is recommended; no user-serviceable optical adjustments exist.
How does it differ from handheld PAL-Urea models?
The RX-5000i provides higher resolution (±0.000040 n_D vs. ±0.0001), active thermal stabilization, and full traceability documentation—making it suitable for regulatory submission and QA release, whereas PAL-Urea is optimized for rapid field screening.