This European standard describes the determination of NOGE components with more than two aromatic rings (the two-ring NOGE is equal to BFDGE = Bis(2-hydroxyphenyl)methane bis(2,3-epoxypropyl)ether) and at least one epoxy group as well as their derivatives containing chlorohydrin functions and having a molecular mass less than 1000 Daltons in can coatings.
A high performance liquid chromatography (HPLC) method is employed based on reversed phase HPLC and fluorescence detection.
The method is capable of determining NOGE and its derivatives at a minimum level of 1 µg/ml in solution.
Direct HPLC analysis of the can coating extract may result in chromatograms difficult to interpret, due to interference from other components or the instability of the monomer resulting in a complex mixture of derivatives and/or reaction products. By forced hydrolysis of all epoxy groups and their reaction products, the quantification of the NOGE is simplified and the identities of the substances are indicatively confirmed.
NOTE In this European standard the term “NOGE and its derivatives” refers to the requirements of Directive 2002/16/EC [1] and its amendment, Directive 2004/13/EC [2]. This includes NOGE components with more than two aromatic rings and at least one epoxy group as well as their derivatives containing chlorohydrin functions and having a molecular mass less than 1000 Daltons.