Urea calibration sets

Urea concentration in milk is a key indicator for dairy herd management, especially in assessing and adjusting feeding strategies. Mid-infrared spectroscopy (MIR) has become the most efficient and reliable technology for performing high-throughput physico-chemical milk analysis.

To maintain accuracy and ensure international consistency of results, MIR instruments such as the DairySpec FT and FTS must be regularly calibrated using high-quality reference materials. That’s why Bentley Instruments has developed dedicated urea calibration sets – a full range of mid-infrared urea SRMs designed to optimize calibration and standardization of milk analyzers.

Bentley Instruments’ urea calibration sets are composed of 30 cow milk samples (40 mL each) covering a typical urea concentration range of 5 to 50 mg/dL. These mid-infrared calibration standards are frozen at –20 °C and contain a stabilizer to preserve sample integrity over time.

Validated specifically for milk urea analysis, these frozen standards offer a reliable and convenient alternative to freshly prepared samples. With a shelf life of up to one year, they enable more frequent and consistent calibration of mid-infrared analyzers like the DairySpec FT and FTS. This helps ensure long-term stability, improved accuracy, and early detection of instrument drift.

The reference values assigned to each urea calibration sample are established using a validated colorimetric reference method performed with the Bentley Instruments ChemSpec analyzer. This method relies on the enzymatic hydrolysis of urea by urease, followed by a colorimetric quantification of the released ammonia. The final urea concentration is determined by calculating the difference between total and initial ammonia levels.

Our urea calibration sets are shipped monthly according to a predefined schedule. Each shipment is prepared in isothermal packaging with ice packs to maintain the cold chain and ensure optimal sample preservation. A sealed water bottle is included to monitor temperature stability upon delivery. All shipments are sent via express carrier for rapid and secure transport.