Substances on their own and in preparations

Reference: http://guidance.echa.europa.eu/substances_en.htm

Substances

The concept of REACH is based on substances. Most obligations refer to substances, whether on their own, in mixtures or in articles.

A substance is defined as a chemical element and its compounds in the natural state or obtained by any manufacturing process, including any additive necessary to preserve its stability and any impurity deriving from the process used, but excluding any solvent which may be separated without affecting the stability of the substance or changing its composition.

Preparation

If two or more substances are mixed together forming a mixture or a solution, the term "preparation" is used.