brilliant blue [ C.I. 42090,D & C blue no.4,F D & C blue #1,FD&C blue No.1,acid blue 9,blue no. 1,brilliant blue Al (3:1) salt,brilliant blue FCF,brilliant blue FCF, diammonium salt,brilliant blue diammonium salt,brilliant blue dipotassium salt,brilliant blue potassium, sodium salt,brilliant blue, aluminium salt,brilliant blue, disodium salt,caries check blue,erioglaucine,food blue 2 ] coal tar derivative food dye; used as the di-NH4 or di-Na salts; RN given refers to parent cpd