ATAGO PAL-Urea Portable Diesel Exhaust Fluid (DEF) Refractometer

Overview

The ATAGO PAL-Urea is a precision handheld refractometer engineered specifically for the rapid, on-site measurement of urea concentration in Diesel Exhaust Fluid (DEF), also known as AUS 32 (Aqueous Urea Solution, 32.5% w/w). Based on the principle of critical-angle refractometry, the instrument determines DEF concentration by measuring the refractive index of the sample at ambient temperature and converting it to mass percentage using a pre-calibrated, traceable polynomial curve aligned with ISO 22241-1 specifications. Unlike generic Brix refractometers, the PAL-Urea applies a proprietary optical algorithm optimized for the linear refractive index–concentration relationship of urea–water systems within the 0–55% range, ensuring metrological validity for compliance-critical applications in fleet maintenance, fuel distribution, and vehicle service centers.

Key Features

• Direct readout in % w/w urea concentration (0.0–55.0%), eliminating manual conversion or lookup tables
• Digital LCD display with automatic temperature compensation (ATC) for ambient conditions between 10–40°C, referenced to 20°C per ISO 22241-2
• High-precision optical prism assembly manufactured from sapphire-grade optical glass, resistant to chemical erosion from DEF exposure
• Compact, ergonomic design (130 × 65 × 45 mm; ~180 g) with IP65-rated enclosure for dust and water resistance during field use
• No external power supply required — operates on two AAA alkaline batteries (typical life: >10,000 measurements)
• Calibration verified using NIST-traceable 32.5% w/w urea standard solution; user calibration lock prevents accidental parameter modification

Sample Compatibility & Compliance

The PAL-Urea is validated exclusively for aqueous urea solutions meeting ISO 22241-1 purity requirements (e.g., absence of aldehydes, metals, and biocides above threshold limits). It is not intended for use with contaminated, degraded, or non-aqueous DEF substitutes. The device supports regulatory verification workflows under ISO 22241-2 (testing methods), DIN 70070 (German automotive standard), and ASTM D7669 (standard test method for urea concentration in diesel exhaust fluid). Its measurement uncertainty (±0.2% w/w) satisfies the ±0.7% tolerance limit specified in ISO 22241-1 Annex A for field-grade instrumentation. For GLP/GMP environments, measurement records can be manually logged with operator ID, time stamp, and batch number to support audit trails.

Software & Data Management

While the PAL-Urea operates as a standalone instrument without embedded data logging or Bluetooth connectivity, its output is fully compatible with external documentation systems used in fleet management and quality assurance departments. Each reading corresponds to a single-point concentration value traceable to the instrument’s factory calibration certificate (included). For laboratories requiring digital integration, ATAGO’s complementary RX-5000i benchtop refractometer offers USB export of raw refractive index (nD), Brix, and % w/w data in CSV format, along with customizable calibration curves and 21 CFR Part 11-compliant user access control and electronic signature functionality.

Applications

• On-vehicle DEF tank sampling during routine maintenance checks to confirm 32.5% ± 0.7% operational concentration
• Verification of DEF batches prior to dispensing at fuel depots or truck stops
• Field diagnostics of SCR system anomalies linked to low-concentration or adulterated DEF
• Training and certification programs for diesel technicians on ISO 22241 compliance protocols
• Third-party inspection agencies conducting roadside DEF quality audits per national emissions regulations (e.g., EPA Clean Air Act enforcement, EU Euro VI monitoring)

FAQ

Why must DEF concentration be precisely 32.5% w/w?
Because the selective catalytic reduction (SCR) catalyst is chemically optimized for stoichiometric reaction with NO_x at this concentration. Deviations reduce NO_x conversion efficiency and may trigger engine derating or fault codes.
Can the PAL-Urea measure other urea-based solutions?
No — its calibration curve is mathematically constrained to the ISO 22241-defined urea–water binary system. Use outside this scope violates metrological validity.
Does ambient temperature affect accuracy?
Yes — though ATC compensates within 10–40°C, measurements below 10°C or above 40°C require thermal equilibration of the sample to ambient before testing.
How often should the instrument be recalibrated?
Annually, or after 5,000 measurements — whichever occurs first — using certified 32.5% w/w reference standard (ATAGO P/N: 2315-001).
Is cleaning required between samples?
Yes — wipe the prism surface with lint-free tissue moistened with deionized water after each measurement to prevent crystallization-induced drift.