The European standard series

Abstract
Changes to the European standard series which have taken place since the last officially recommended alterations in 1988, are explained. New to the series is the sesquiterpene lactone mix. The PPD black rubber mix and the quinoline mix have been replaced by single components; one of the p-hydroxybenzoates has been left out of the paraben mix. Ethylenediamine dihydrochloride has been dropped from the series.