New Refractometer Monitors Urea-Based Diesel Exhaust Fluid for Diesel Engines Equipped with Selective Catalytic Reduction Technology

MISCO Urea Refractometer DEF-201

New Tester Measures Urea Concentration in Diesel Exhaust Fluids; Helps Defeat DEF Tampering

The MISCO Palm Abbe DEF-201 is a handheld digital refractometer designed specifically for testing the concentration of urea-based Diesel Exhaust Fluid (DEF). Diesel Exhaust Fluid, which is required for diesel-powered vehicles employing Selective Catalytic Reduction (SCR) technology, must be maintained within a very narrow concentration range of less than 1.5% in order to receive API Certification and meet international standards.

This straightforward refractometer test requires only a few drops of urea-based Diesel Exhaust Fluid, and a couple of seconds, to obtain a digital reading of urea concentration with a precision of +/-0.1%. Proper urea concentration is critical for sustaining reduced diesel emissions which, besides being good for the environment, can save the Diesel Exhaust Fluid consumer money, prevent damage to expensive SCR components, and help identify tampering.

Simply place a few drops of DEF in the refractometer’s stainless-steel well, close the evaporation cover, and press a single button to obtain a near instantaneous reading on the large 24-character backlit display. The refractometer can be quickly calibrated to water, with the touch of a button.

Key to the refractometer’s precision is MISCO’s proprietary OPTICAL-ENGINE®, which combines high-index sapphire optics (the next hardest substance to diamond) with a detector array containing more than a 1,000 detector elements. The instrument also boasts an optimized combination of hardware and software which automatically temperature compensates the reading specifically for aqueous urea solutions.

In addition to reading DEF, the refractometer can be programmed to read up to four more critical automotive parameters such as engine coolant freezing-point, engine coolant concentration, brake fluid water content, and windshield washer fluid. Each refractometer bears a laser-etched serial number for traceability. Options for the instrument include a rubber-armor jacket (in one of three colors), a virtually indestructible storage case, and NIST traceable certified calibrations.

The following standard instruments and scales are available:


A world leader in the refractometer field, MISCO is headquartered in Cleveland, OH, home to the company for 60 years. MISCO designs, manufacturers and sells a variety of refractometers, including: digital bench-top laboratory refractometers, inline process control refractometers, digital handheld refractometers, and traditional handheld instruments. For more information, please call (216) 831-1000, or access MISCO’s web site at

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