Mercaptosuccinic Acid from Canada
Mercaptosuccinic acid (thiomalic acid) contains both mercapto and dicarboxylic acid functions in a single molecule. Falls under HTS 2930.90.4920 as 'other mercaptocarboxylic acids' since organo-sulfur takes precedence over oxygen functions per Chapter 29 classification rules. Used in heavy metal detoxification.
Duty Rate — Canada → United States
4.2%
Rate breakdown
9903.03.030%Articles the product of any country, as provided for in subdivision (aa)(ii) of U.S. note 2 to this subchapter
Import Tips
• Provide quantitative analysis showing free -SH and -COOH groups for dual-function classification
• Classify as UN 3265 Corrosive solid, pH <2 requires specific packaging
• Document research/pharma end-use to avoid 2917 polycarboxylic acid misclassification