In T 12/81 (OJ 1982, 296, see above) the board stated that it is permissible to make the definition of a chemical substance more precise by additional product parameters such as melting point, hydrophilic properties, NMR coupling constant or product-by-process claims if it cannot be defined by a sufficiently accurate generic formula. From this it necessarily follows that patent documents using such definitions will be prejudicial to the novelty of later applications claiming the same substance defined in a different and perhaps more precise way.
In T 352/93 it was decided that a claim for an ionic compound (salt) that was defined only by structural parameters, i.e. the structural formulae of the cation and anion of the compound, was not novel over prior art disclosing an aqueous solution that contained a base corresponding to the cation and an acid corresponding to the anion.
In T 1336/04 the board stated that, according to case law, (see, inter alia, T 767/95 and T 90/03 of 17 March 2005), the preparation of an enzyme sufficiently pure to allow sequencing was novel over a preparation which was not in such a state of purity.
In T 767/95 concerned the purification of interleukin-1Beta (IL-1Beta), a high molecular weight protein (17.5 kDa). The board found that a purified homogeneous preparation of IL-1Beta was novel over a semi-purified mixture of proteins containing IL-1Beta. A relevant consideration was the provision of IL-1Beta in a degree of purity that allowed the determination of its (partial) amino acid sequence, whereas "no analysis of the amino acid sequence of IL-1 that would provide definitive proof of the homogeneity of IL-1 preparations" was found in the prior art (see also T 90/03, T 29/05).