Hematoxylin, C.I. 75290 (Natural Black 1), is a certified biological stain powder used to prepare staining solutions for histology and cytology. Hematoxylin is widely used as the starting material for nuclear staining formulations, including hematoxylin and eosin (H&E) procedures.
Related names: Haematoxylin; C.I. 75290; Natural Black 1.
In most hematoxylin staining formulations, hematoxylin is oxidized to hematein and combined with a metal mordant. The resulting hematein-metal complex provides the staining activity associated with common hematoxylin formulations. Staining characteristics therefore depend on the complete formulation, including oxidant, mordant, pH, concentration, and staining procedure.
Biological Stain Commission certification is lot-specific. Certified dry-stain lots are evaluated against applicable chemical and staining-performance criteria. When lot-specific certification documentation is required, verify the certification information associated with the supplied material.
Key Properties
- Certified biological stain powder for histology and cytology
- C.I. Number: 75290
- Colour Index name: Natural Black 1
- CAS Number: 517-28-2
- Molecular formula: C16H14O6
- Molecular weight: 302.3 g/mol
- Appearance: fine beige to tan to light brown powder
- Light-sensitive material
- Catalog number: 02749
- Package sizes: 25 g and 100 g
Applications
Histology Stain Preparation
Hematoxylin is used as a starting reagent in preparation of hematoxylin-based staining solutions for histological tissue sections. The staining properties of the final reagent depend on oxidation of hematoxylin to hematein and formation of the appropriate metal-mordant complex.
Nuclear Staining
Properly formulated hematoxylin staining solutions are widely used for nuclear staining. In routine histology, hemalum formulations produce blue to blue-purple nuclear contrast after the required staining and bluing steps.
Hematoxylin & Eosin Staining
Hematoxylin-derived nuclear stains are used with eosin counterstains in H&E procedures to provide contrast between nuclei and surrounding tissue components. Laboratories seeking prepared hematoxylin reagents may also consider Harris Hematoxylin, Acidified or Mayer's Hematoxylin.
Cytology Staining
C.I. 75290 is also certified for cytology. Hematoxylin-derived formulations are used as nuclear stains in cytological procedures, with staining behavior determined by the selected formulation and protocol.
Compatibility & Bonding Considerations
- Hematoxylin powder is a starting reagent and is not equivalent to a prepared hematoxylin staining solution
- Most hematoxylin staining methods require oxidation to hematein and complexation with a metal mordant
- Staining behavior depends on formulation variables including oxidant, mordant, pH, concentration, staining time, and differentiation or bluing steps
- Harris, Mayer's, Gill's, and other hematoxylin formulations are chemically and procedurally distinct and should not be treated as interchangeable without method validation
- Certification applies to the certified dry-stain lot rather than to staining solutions subsequently prepared from the powder
Select the preparation method according to the intended histology or cytology protocol. Color development, nuclear contrast, staining intensity, and differentiation behavior depend on the complete hematoxylin formulation rather than hematoxylin powder alone.
Application Tips
- Prepare hematoxylin solutions according to the validated formulation selected for the intended staining method
- Control oxidation, mordant concentration, pH, staining time, differentiation, and bluing conditions when reproducible nuclear staining is required
- Maintain consistent fixation, section preparation, staining time, and reagent preparation when comparing specimens
- Protect the dry powder from unnecessary light exposure during storage and handling
- When BSC certification documentation is required, verify the lot number and certification information associated with the supplied stain powder
Handling & Storage
- Store at room temperature in a cool, well-ventilated location
- Protect the material from unnecessary light exposure
- Ensure good laboratory ventilation during handling and reagent preparation
- Avoid contact with the eyes
- Wear protective gloves, safety glasses, and suitable protective clothing
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FAQ
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1. What is Hematoxylin C.I. 75290 used for?
Hematoxylin is used as a starting reagent for preparing biological staining solutions used in histology and cytology. Hematoxylin-derived formulations are especially associated with nuclear staining, including hematoxylin and eosin procedures.
2. Is hematoxylin itself the active staining species in a hematoxylin solution?
Generally, no. Hematoxylin is oxidized to hematein during preparation or maturation of most staining formulations. Hematein then complexes with a metal mordant to form the staining species responsible for the characteristic nuclear staining of many hematoxylin methods.
3. What does C.I. 75290 or Natural Black 1 mean?
C.I. 75290 is the Colour Index designation associated with Natural Black 1. Both hematoxylin and its oxidized form, hematein, are included under this Colour Index designation.
4. What does certification mean for Hematoxylin C.I. 75290?
Biological stain certification is lot-specific. Certified dry-stain lots are tested against applicable chemical and staining-performance criteria. When certification documentation is required, confirm the lot number and certification information associated with the supplied material.
5. What package sizes are available?
Hematoxylin, C.I. 75290, Cat. 02749, is available in 25 g and 100 g packages. For larger quantities, use the bulk-quote option.
Safety & Documentation
Hematoxylin powder can cause serious eye irritation. Use good laboratory ventilation and appropriate personal protective equipment, including gloves and safety glasses. Refer to the product Safety Data Sheet (SDS) for complete handling, storage, first-aid, and disposal guidance.
