Mercaptosuccinic Acid
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.
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Alternative Classifications
This product could be classified differently depending on its characteristics or intended use.
If for plasticizer-grade dicarboxylic acids lacking sulfur
Chapter 29 rule prioritizes organo-sulfur (2930) over carboxylic plasticizers (2918).
If imported as diagnostic reagent kit component
Lab reagents in kits shift to Chapter 38 per Chapter 29 exclusion notes.
If containing arsenic or other heteroatoms linked to carbon
Chapter 29 note 5 moves multi-heteroatom compounds to 2931 organo-inorganic.
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Import Tips & Compliance
• 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
Related Products under HTS 2930.90.49.20
Thioglycolic Acid
Thioglycolic acid (mercaptoacetic acid), HSCH2COOH, is a chemically defined organic compound containing a mercapto (-SH) group directly linked to a carbon atom and a carboxylic acid function. It falls under HTS 2930.90.4920 as a mercaptocarboxylic acid within the organo-sulfur compounds of Chapter 29. Commonly used in hair perming solutions, metal extraction, and polymer synthesis.
2-Mercaptopropionic Acid
2-Mercaptopropionic acid (HS-CH2-CH2-COOH) is an organo-sulfur carboxylic acid with both mercapto and carboxyl groups on adjacent carbons. Classified under HTS 2930.90.4920 as 'other mercaptocarboxylic acids' per Chapter 29 notes defining organo-sulfur compounds. Used in pharmaceutical intermediates and chelating agents.
3-Mercaptopropanoic Acid
3-Mercaptopropanoic acid features a three-carbon chain with terminal mercapto and carboxylic acid groups. This separate chemically defined compound qualifies under HTS 2930.90.4920 as a mercaptocarboxylic acid per Chapter 29 scope. Applied in polymer cross-linking and biochemical research.
2-Mercaptobenzoic Acid
2-Mercaptobenzoic acid (thiosalicylic acid) combines aromatic carboxylic acid with ortho-mercapto group. Classified in HTS 2930.90.4920 as aromatic mercaptocarboxylic acid under organo-sulfur compounds. Key intermediate for thioindigo dyes and pharmaceuticals.
4-Mercaptobenzoic Acid
4-Mercaptobenzoic acid features para-substituted mercapto and carboxylic groups on benzene ring. HTS 2930.90.4920 classification as aromatic mercaptocarboxylic acid per Chapter 29 organo-sulfur provisions. Utilized in nanotechnology and self-assembled monolayers.
Captopril
Captopril, (2S)-1-[(2S)-3-mercapto-2-methylpropionyl]-L-proline, contains a mercaptocarboxylic acid side chain. Despite complex structure, classified under HTS 2930.90.4920 as its mercapto acid functionality defines the organo-sulfur nature per Chapter 29. Pharmaceutical API for hypertension treatment.