Our advice
The mole and the International System of Units (SI)

Primary methods and reference materials are recognized and accepted means of ensuring the traceability of measurements in chemistry and biology. However, they do not cover all situations. Many traditional methods, for example in the food industry, pose problems because the measurand is very difficult to define. Just think of dietary fiber. Yet these methods are often of great importance when it comes to assessing product quality.

For these measurands, there are generally no CRMs. MREs may exist, or it may be possible to prepare synthetic matrices. If these various solutions prove difficult, there is always the option of comparing your measurements with those of another laboratory, preferably...