Description

Naphthol Yellow S is a water-soluble, anionic monoazo dye belonging to the class of acid dyes. It serves as a vital colorant and biological stain, valued for its bright yellow hue and good lightfastness in specific applications. This product is essential for manufacturers and laboratories in the textile, biological research, and ink formulation industries seeking a reliable and consistent yellow pigment.

Application

• Textile Dyeing: Used for coloring wool, silk, and polyamide fibers, providing a bright yellow shade.
• Biological Staining: Employed as a cytoplasmic stain in histology and microscopy for contrast enhancement.
• Ink Manufacturing: Acts as a colorant in the formulation of writing inks, stamp pad inks, and specialty printing inks.
• Paper Coloring: Utilized for tinting paper products where a stable yellow color is required.
• Leather Dyeing: Applied in the leather industry for dyeing hides and finished leather goods.
• Food Contact Material Coloring: May be used for coloring packaging materials (subject to regional regulatory compliance).
• Indicator Chemistry: Can function as a pH indicator in certain analytical chemistry applications.
• Laboratory Reagent: Serves as a chemical reagent in various research and quality control procedures.

Basic Information

Product Name	Naphthol Yellow S
CAS No.	846-70-8
Molecular Formula	C10H4N2Na2O8S2
Molecular Weight	358.25 g/mol
Synonyms	Acid Yellow S; Acid Yellow 1; CI 10316; Flavianic acid sodium salt; 2,4-Dinitro-1-naphthol-7-sulfonic acid disodium salt; Naphthol Yellow; Naphthol Yellow S (sodium salt); 7-Hydroxy-8-(2,4-dinitrophenylazo)-1,3-naphthalenedisulfonic acid disodium salt
EINECS	212-690-2

Quality Control

Our Naphthol Yellow S is manufactured under a stringent quality management system to ensure batch-to-batch consistency and reliability. Each lot undergoes comprehensive testing, including identification, purity assay, and impurity profiling. A Certificate of Analysis (COA) detailing specifications such as color strength, solubility, and heavy metal content is provided with every shipment to guarantee it meets the requirements for your specific industrial or laboratory application.

Storage

Preserve in a tightly closed container, protected from light. Store in a cool, dry, and well-ventilated area at room temperature (15-25°C). This material is hygroscopic (moisture-sensitive); keep the container tightly sealed when not in use to prevent absorption of atmospheric moisture, which may affect performance.

Specification

Item	Specification
Appearance	Yellow to orange-yellow powder
Identification (IR)	Conforms to standard
Assay (HPLC)	≥ 85% (as is)
Loss on Drying	≤ 5.0 %
Sulfated Ash	≤ 30.0 %
Solubility (in Water)	Clear, yellow solution
Heavy Metals (as Pb)	≤ 20 ppm
Absorbance (λ max)	425 - 435 nm

Note: Specifications can be tailored. Please contact us for the detailed technical data sheet of a specific grade.