4-(Dimethylamino)benzaldehyde-d11 is the labelled isotope of 4-(Dimethylamino)benzaldehyde(D461260) which is used in Ehrlich''s reagent for spectrophotometric determination of hydrazine as it reacts to form azo dyes. 4-(Dimethylamino)benzaldehyde is used for determination of urine bilirubin and porphobilinogen. Dyes and metabolites.