Optical Brightener ER-I 1.Purity: >99% 2.Volatile content:<0.50% 3.Ash ... .10% 4.Yellowish-green crystalline solid Optical Brightener ER-IC.I. 199 Molecular Formula: C24H16N2 Molecular Weight : 332 Appearance: Yellowish-green ... than 99% and a melting point of 229 to 231ºC.It is non-toxic, odorless, non-ionic and soluble in ... barrel. contact Ruby Lu, ruby at tiandiyi dot cn. ER-I