This document specifies a direct method for the determination of the total oxygen content in bio-based products using an elemental analyser. The scope is limited to products containing elements carbon, hydrogen, oxygen, nitrogen, chloride, bromide and iodide without fluoride, representing at least 95 % of the composition of the product to be analysed. NOTE 1 Bio-based materials can contain both organic and inorganic components. The oxygen content might originate both from the organic and/or the inorganic components. The inorganic components are not bio-based but will nevertheless contribute to the amount of oxygen determined by the following prescribed methods and therefore influence the results in terms of oxygen content. According to the current state of the art, it is not possible by isotopic measurements to establish a distinction between oxygen originating from biomass and oxygen originating from non-biomass. NOTE 2 Although this document has been drafted for the purpose of the determinations dealing with bio-based content, it can be also used as a standalone standard for determination of oxygen in organic compounds. NOTE 3 For the purposes of this document, the unit "% (m/m)" is used to represent the oxygen content of a material. NOTE 4 The method specified in this document involves a direct measurement method for the determination of oxygen content. This method contains many similarities with the ASTM D5622 [1] standard for gasoline and methanol fuels. The method specified in this document is specifically developed and validated for bio-based products. In addition, this method provides more accurate and unadulterated measured values for oxygen in contrast to indirect measurement methods for the determination of oxygen (e.g. ASTM D 3176 [2]).

NEN-EN 17351:2020 -

DS/EN 17351:2020 -