cas: 131-27-1 Molecular Formula: C10H9NO6S2 Molecular weight:303.31 Appearance: Grey or slightly reddish powder We provide quality and low price dye intermediate such as 2-Amino-4 8-naphthalenedisulfonic acid (cas: 131-27-1). If you are interested in our products, please hesitate to contact with us. We would like to give you our lowest price to help you cut your production cost.