E-liquid flavorings might contain some unwanted substances like diacetyl, acetylpropionyl, or acetoin. The type of undesired substances, released when heating the liquid in an e-cigarette, depends on the added aroma.
For this reason, it is mighty important to always carefully read the documentation attached to a given raw material. Moreover, a reliable supplier should always be able to provide Safety Data Sheets and/or Certificates of Quality to prove their own transparency. If you don’t know what to pay attention to when reading the documentation accompanying the raw materials, you can check our previous article on this topic: How to read product certificates?
Remember that aromas are highly complex chemical mixtures. Their composition may include up to several hundred ingredients, and in accordance with the TPD directive, with a concentration equal to or greater than 0,1 %, they are not considered confidential and should be mentioned on the label. Therefore, if acetoin, propionyl, or another chemical compound are present in the composition of a given aroma in a lower amount, they may not be shown on the packaging.
Another legislation that covers chemicals is CLP. It states, that the label on the packaging must contain a list of A1 category sensitizing substances that appear in the number of 0,01%, and more, of the whole product.
To sum up, depending on the regulations, the list of components on the label or in the MSDS will vary, based on the substances’ type and their quantity.
What is also important, full traceability of raw materials is a must! You should always be able to identify the source of any raw material used in the production of a given e-liquid. That allows to fully influence and supervise the quality of the final product.