DEQUEST 2010 (HEDP) 1. Hydroxyethylidene,.1.1 Diphosphonic Product Description Acid Chelating agent stabilizer of peracetic acid and hydrogen peroxide.DEQUEST 2010. DEQUEST 2010. INCI. 1-Hydroxyethylidene (1,1-Diphosphonic Acid). Chemical family. Chelators.