Check the certificate for your batch

The four numbers to check

A certificate lists about 20 results. These four tell you most of what you need to know. They are numbered and highlighted on the example certificate.

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1. 1
   Urea contentLimit: 31.8 – 33.2 % · Example: 32.3 % ✓

   The strength of the solution. SCR systems dose as if it is 32.5 %.

2. 2
   Refractive index at 20 °CLimit: 1.3814 – 1.3843 · Example: 1.3829 ✓

   A second strength check, and the one you can do on site with a refractometer.

3. 3
   BiuretLimit: 0.3 % max · Example: 0.28 % ✓

   Forms when urea breaks down from poor raw material or heat. Leaves deposits in the injector.

4. 4
   SodiumLimit: 0.5 mg/kg max · Example: 0.3 mg/kg ✓

   The key contamination check. Sodium comes from dust, dirt and impurities in the air and water, and gets into tanks through open lids, vents and dirty transfer gear. It permanently poisons the SCR catalyst.

Judge each result against the Limits columns. The Acceptance Range columns are the lab's allowance for test repeatability. Check that the batch number matches your label.

Download the 2-page guide (PDF)Free AdBlue® check

How to read an AdBlue^® Certificate of Analysis

A CoA lists the lab results for one production batch against the limits in ISO 22241-1. These are the lines that matter most, and what each one tells you.

The certificate also shows the batch number and production details, so you can match it to the label on your drum or IBC. More detail is in our CoA guide and ISO 22241 explainer.

Using batch records in your workshop or fleet

• Record the batch on receipt. Note the batch number and fill date from the label when the delivery arrives, alongside the delivery docket.
• Keep the CoA with your maintenance records. If a vehicle throws an SCR fault or goes into derate, you can show exactly what went into it.
• Use oldest stock first. The fill date on the label tells you which pack to open next.
• Keep a sealed sample when you suspect a fault. A clean, sealed sample from the tank or pack is what a lab needs. Label it with the batch number and the date it was taken.
• Ask suppliers for the same. If a supplier can't give you a batch number and CoA for what they delivered, you have nothing to check it against.

Auditors, principal contractors and councils often ask for proof of product quality. A batch CoA plus the VDA licence number (No. 0005569) usually covers it. See certification and QC.