Mercaptosuccinic Acid from China
Mercaptosuccinic acid (HSCH₂CH(COOH)CH₂COOH) is a di-carboxylic acid with thiol functionality, classified under HTS 2930.90.4950. Contains sulfur directly bonded to carbon; excluded from cyclic anhydrides per note 8. Used in heavy metal chelation and polymer modification.
Duty Rate — China → United States
41.7%
Rate breakdown
9903.88.0325%Except as provided in headings 9903.88.13, 9903.88.18, 9903.88.33, 9903.88.34, 9903.88.35, 9903.88.36, 9903.88.37, 9903.88.38, 9903.88.40, 9903.88.41, 9903.88.43, 9903.88.45, 9903.88.46, 9903.88.48, 9903.88.56, 9903.88.64, 9903.88.66, 9903.88.67, 9903.88.68, or 9903.88.69, articles the product of China, as provided for in U.S. note 20(e) to this subchapter and as provided for in the subheadings enumerated in U.S. note 20(f)
9903.05.3112.5%Section 301 (forced labor) — additional 12.5% ad valorem on products of China
Import Tips
• Provide molecular weight and functional group analysis confirming non-cyclic structure
• Certify heavy metals <10ppm for chelation grade material
• Document acid dissociation constants to validate di-carboxylic acid status