Toluidine Blue O (Basic Blue 17) from China
Toluidine Blue O is a thiazine dye derived from toluidine, used in histology and microbiology staining. While primarily a colorant, its toluidine base and chemical purity qualify it under HTS 2921.43.90 rather than Chapter 32 when imported as pure compound. Pharmaceutical grade requires >85% purity.
Duty Rate — China → United States
44%
Rate breakdown
9903.05.3112.5%Except for products described in headings 9903.05.85–9903.05.92, articles the product of China, as provided for in U.S. note 52 to this subchapter
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)
Import Tips
• Provide dye index number (C.I. 52040) and absorption spectrum for identity confirmation
• Pharma grade requires USP/NF certificate; technical grade may face 3204 scrutiny
• Declare metachromatic staining end-use to support Chapter 29 classification