Martius Yellow Indicator - BioReagent

Cat. No.: M1528836

GRADE & PURITY BioReagent

Storage

Room temperature

Shipped In

Normal

Overview

Martius Yellow Indicator, also known as 2,4-dinitro-1-naphthol, CAS No.: 605-69-6, molecular formula: C₁₀H₆N₂O₅, molecular weight: 233.16. This product is an acidic pH indicator with a color transition range of pH 2.0 to 4.0. The acid form is colorless (bright colorless), while the alkaline form is yellow. It is suitable for endpoint determination in acidic titration systems and visual pH detection.

Specifications

Specifications & Purity

BioReagent

Storage

Room temperature

Shipped In

Normal

Grade

BioReagent

Product Line

biological_products

Application Protocols

No item-specific, validated application protocols or dilutions are provided for this SKU. The following are general literature-based workflow outlines; users should optimize for their specimen, fixation, and equipment.

• General preparation:

  • Prepare a 0.1–1.0% w/v stock in ethanol or DMSO. For aqueous application, dissolve in mildly basic buffer then adjust to working solvent/pH.
  • Filter the solution and store protected from light. Prepare fresh working solutions regularly.

• Example use within MSB-style trichrome (literature, qualitative):

  • Deparaffinize and hydrate sections.
  • Stain with Martius Yellow working solution briefly (e.g., 1–5 min), rinse.
  • Proceed with Scarlet/Acid Fuchsin and phosphotungstic/phosphomolybdic acid differentiation, followed by aniline blue for collagen. Times and concentrations must be empirically tuned.

• Quality control:

  • Include a known positive control tissue (e.g., spleen or fibrin-rich tissue) when developing or modifying protocols.
  • Document solvent composition, pH, and exposure times; small changes can materially alter contrast and background.

These outlines are for research use only and are not standardized test methods.

Biological Roles

This product is supplied as a laboratory dye/indicator. It is not a biomolecule or enzyme and has no endogenous biological role. The following notes provide context for its use in biological laboratories (literature/general):

• Functional context in histology:

  • Acts as a small-molecule chromophore that noncovalently associates with tissue components through hydrophobic interactions, hydrogen bonding, and electrostatic contacts (in its anionic form). This differential affinity underpins its role as a counterstain in multicolor histological techniques.
  • In MSB/Movat-type stains, Martius Yellow preferentially colors erythrocytes and certain fibrin components, aiding discrimination from collagen and muscle fibers when used with complementary dyes (e.g., Scarlet/Brilliant Blue).

• Spectral behavior relevant to bioassays:

  • Exhibits pH-sensitive absorbance; deprotonation typically enhances solubility and can shift λmax, which may be exploited for qualitative indication or endpoint visualization (literature). For quantitative assays, calibration in the exact buffer/solvent system is required.

• Biological activity and toxicity:

  • No physiological or signaling role. As with many nitroaromatic dyes, excessive exposure may affect cellular systems; therefore, it is used only for ex vivo staining and research workflows. Observe appropriate waste and exposure controls.

• Research-use limitation (from Product Data): For research use only. Not for human or veterinary applications.

Buffer Applications

Martius Yellow is not a buffering agent and is not typically used to prepare buffer solutions. Its relevance to buffers is as a pH-sensitive chromophore in certain indicator formulations (literature/general):

• Indicator use in buffers (literature):

  • The phenolic dye exhibits pH-dependent spectral changes that can be harnessed as a qualitative acidity/basicity indicator in specific, narrow ranges defined by method conditions. Exact transition ranges are formulation- and solvent-dependent and are not specified for this item.
  • In staining protocols, mildly acidic or ethanolic buffers are often employed to control dye uptake and differentiation rather than to leverage precise pH transitions.

• Practical guidance:

  • If using as an indicator within a buffer, empirically determine the color/absorbance transition under your exact ionic strength, solvent composition, and temperature.
  • For buffer making and pH control, select established buffering agents (e.g., phosphate, Tris, acetate) and use Martius Yellow only as a visualization aid if validated by your method.

Green Alternatives

When selecting a yellow counterstain/indicator, consider solvent use, hazard profile, and waste minimization (literature/general):

• Comparison of options (literature; qualitative):

  • Martius Yellow (nitroaromatic phenol):
    • Pros: robust color, established histology protocols (MSB/Movat), good ethanol solubility.
    • Considerations: nitroaromatic content; limited water solubility at neutral pH; potential for higher aquatic persistence.
  • Naphthol Yellow S (sulfonated analog):
    • Pros: improved water solubility; may reduce need for organic cosolvents.
    • Considerations: different staining selectivity; sulfonate increases anionic character and tissue interactions.
  • Tartrazine (FD&C Yellow 5, azo dye):
    • Pros: high aqueous solubility; broad availability; potentially simpler waste handling for dilute streams.
    • Considerations: different spectral profile and tissue affinity; may not substitute in legacy protocols without revalidation.

• Greener practice tips (applicable regardless of dye):

  • Use aqueous/ethanolic systems instead of high-boiling polar aprotics when feasible.
  • Right-size batch volumes; prepare only what is needed to limit expired waste.
  • Implement microvolume staining or slide racks that minimize bath volumes.
  • Capture dye-containing rinses for appropriate waste segregation to reduce environmental discharge.

No item-specific environmental certifications are provided; assess alternatives based on your protocol requirements and institutional green chemistry guidelines.

Pharmaceutical Uses

No item-specific pharmacopeial status or excipient designation is provided for this product. Martius Yellow is supplied as a BioReagent for research and laboratory use only.

• General, non-clinical context (literature/general):

  • Small-molecule dyes may be used in industrial and research settings for visualization, tracer studies, or process diagnostics. However, absence of pharmacopeial monographs and compliance data means this material is not intended for pharmaceutical formulation.
  • If a colorant is required in a regulated context, select a dye with established compendial status (e.g., USP/NF-listed color additives) and obtain appropriate regulatory documentation.

• Manufacturing/lab utility:

  • Potential roles in R&D include visualization in filter integrity tests, solvent front tracking in TLC, or as a staining component during excipient or tissue studies. Such uses require internal qualification and are outside the scope of approved drug product excipients.

• Compliance note:

  • For any use related to human or veterinary products, do not use this material. Source a grade with explicit GMP/compliance documentation and specification alignment.

Physical Properties

Only item-specific values present in Product Data are reported as such. Additional values below are literature/general for Martius Yellow (2,4-dinitro-1-naphthol) and should be verified against the CoA for your lot.

• Item-specific (from Product Data):

  • Grade/Purity: BioReagent
  • Appearance: Not specified for this item; refer to CoA/Spec Sheet.
  • Molecular Weight: Not specified for this item; refer to CoA/Spec Sheet.

• Literature/general properties (for context; non-spec):

  • Physical state/color: yellow to orange crystalline solid (literature; dye).
  • Melting point: often reported ~160–170 °C (decomp. possible; literature). Exact MP varies with purity and polymorph.
  • Boiling point: not applicable (decomposes before boiling under ambient pressure; literature).
  • Density: data scarce; typically around 1.5–1.7 g/cm³ for nitroaromatic naphthols (qualitative, literature). Use for qualitative comparison only.
  • Solubility: sparingly soluble in water; more soluble in ethanol, methanol, acetone, and readily soluble in alkaline aqueous solutions due to phenolate formation (literature). Good solubility in DMSO and DMF (literature).
  • Acid–base: weak acid (phenolic pKa generally ~7–10 for nitro-activated naphthols; literature, compound-specific value varies in sources). Deprotonation shifts absorption maxima (indicator behavior).
  • UV–Vis: intense absorption in the blue/violet leading to yellow color; λmax depends on solvent and pH (literature). For quantitative work, determine λmax in your exact matrix.
  • Partition behavior: increased aqueous solubility upon basification; otherwise prefers organic phase (literature).

Note: Do not treat literature values as specifications; confirm with experimental data or the item’s CoA.

Quality & Grades

• Item-specific grade (from Product Data):

  • BioReagent grade: suitable for biological and biochemical laboratory use (research use only). Typically emphasizes consistency, low bioburden, and performance in staining/indicator applications rather than ultra-trace inorganic/organic impurity control (which would be specified separately if applicable). No additional assay or stabilizer information is provided for this SKU.

• What BioReagent grade implies (general):

  • Intended for research workflows in life science and histology where dye performance, color strength, and batch-to-batch consistency are important.
  • Not certified for diagnostic or therapeutic use. Not intended for clinical procedures.
  • UV cutoff, water content, metal traces, or specific contaminant limits are NOT specified for this item; refer to CoA/Spec Sheet if such data are critical to your application.

• Stabilizers/additives: Not specified for this item; refer to CoA/Spec Sheet. Many dyes are supplied neat; if any wetting agents or salts are present, they would be listed on the CoA.

• Documentation best practices:

  • For quantitative histochemistry or method validation, document lot number and confirm performance (e.g., absorbance at λmax, staining intensity) under your exact protocol.
  • If using spectrophotometric assays, determine extinction coefficients in your solvent/pH system; these are method-dependent and not specified here.

Reaction & Applications

• This product is supplied and graded as a BioReagent dye/indicator. It is primarily used as a staining reagent rather than as a synthetic intermediate.

• Laboratory applications (literature/general):

  • Histology/cytology: classic counterstain for fibrin and erythrocytes; incorporated into multichromatic methods such as MSB (Martius–Scarlet–Blue) and Movat-type pentachrome variants, where Martius Yellow imparts yellow coloration to red blood cells and certain extracellular components.
  • Indicator behavior: as a phenolic nitroaromatic dye, exhibits pH-dependent color intensity/absorbance shifts that can be leveraged in qualitative acidity/basicity indication within specific formulation ranges (method-dependent; literature).
  • Staining of mineralized tissues and connective components where differential affinity and diffusion rates are useful to distinguish structures (protocol-specific; literature).

• Practical notes for use (literature):

  • Prepare fresh working solutions to minimize precipitation and color drift; filter before application to tissue.
  • Control solvent composition (e.g., aqueous ethanol) and ionic strength; these parameters affect dye uptake and background.
  • Rinse and differentiation steps (e.g., with acidified alcohol) are often used to sharpen contrast in trichrome protocols; optimize times empirically on your tissue type.

• Not typically used for: organometallic reactions, cross-coupling, or general synthetic transformations. For such chemistry-focused topics, see Synthetic Utility for limited notes.

Reaction Conditions

As supplied, this product is intended for use as a reagent/stain rather than as a synthetic substrate. The following general literature guidance may assist in solution preparation and, if relevant, dye modification studies. These are NOT specifications for this SKU.

• Solution preparation (literature/general):

  • Stock solutions: 0.1–1.0% w/v in ethanol, 70–95% ethanol–water, or DMSO commonly dissolve the dye efficiently. Filter through 0.22–0.45 µm before use in staining.
  • Aqueous basic solutions: Dissolve in 0.01–0.1 M carbonate/bicarbonate to form the phenolate; adjust pH as required for the staining protocol.

• Staining protocols (qualitative ranges; literature):

  • Temperature: ambient (20–25 °C) for most histology workflows.
  • Exposure times: from seconds to several minutes depending on tissue thickness and desired contrast; optimize empirically.
  • Differentiation: brief rinses with acidified alcohol or buffered solvents to reduce background.

• Chemical transformations (if modifying the dye; literature):

  • O-alkylation: base (K2CO3/Cs2CO3) in acetone/DMF, 20–60 °C; hours.
  • Nitro reduction: catalytic hydrogenation (Pd/C, H2) or Fe/AcOH; 0–50 °C; monitor carefully to avoid over-reduction and azo coupling side reactions.

Always validate conditions on small-scale trials and consult primary literature for your exact application. None of the above are product specifications.

Safety & Handling

• Item-specific GHS/SDS data (from Product Data):

  • Signal Word: Not specified for this item; refer to SDS.
  • H-Statements: Not specified for this item; refer to SDS.
  • GHS Classification: Not specified for this item; refer to SDS.
  • Pictograms: Not specified for this item; refer to SDS.

• General safety considerations for nitroaromatic phenolic dyes (literature/general):

  • Hazards: May cause skin/eye irritation and respiratory irritation. Nitroaromatics can present systemic toxicity upon significant exposure. Avoid dust generation; handle in a fume hood when weighing.
  • PPE: Lab coat, safety glasses or splash goggles, and appropriate chemical-resistant gloves (e.g., nitrile). Use a dust mask or respirator if airborne dust cannot be controlled (per risk assessment).
  • First aid (overview; defer to SDS):
    • Inhalation: Move to fresh air; seek medical attention if symptoms persist.
    • Skin contact: Wash with soap and water; remove contaminated clothing.
    • Eye contact: Rinse cautiously with water for several minutes; seek medical attention for persistent irritation.
    • Ingestion: Rinse mouth; do not induce vomiting; seek medical attention.
  • Handling/storage incompatibilities: Strong oxidizers and strong reducing agents; strong bases/acids may cause rapid dissolution or degradation. Avoid elevated temperatures and ignition sources. Although not a classic peroxide-forming solvent, maintain good housekeeping to minimize dust accumulations.
  • Environmental precautions: Dyes can be persistent; prevent release to the environment. Collect spills with inert absorbent and dispose of according to institutional and local regulations.

Always consult the product-specific SDS for authoritative hazard, exposure limits, and emergency procedures.

Solvent Selection

Martius Yellow is an aromatic phenolic dye. Its solubility and spectral behavior are strongly solvent- and pH-dependent (literature). Choose solvents to match your workflow:

• Polarity and miscibility (literature/general):

  • Sparingly soluble in neutral water; readily soluble upon basification (formation of phenolate anion).
  • Good solubility in polar organic solvents (ethanol, methanol, acetone) and dipolar aprotic solvents (DMSO, DMF).

• Typical dissolution strategies (literature):

  • Prepare concentrated stocks in ethanol or DMSO, then dilute into aqueous buffers as needed. Filter (0.22–0.45 µm) to remove particulates before use in imaging/histology.
  • For aqueous-only systems, dissolve in a mildly basic buffer (e.g., carbonate/bicarbonate) to aid solubility, then adjust pH to working conditions if compatible with the staining protocol.

• Comparative notes (literature/general):

  • Versus sulfonated analogs (e.g., Naphthol Yellow S): sulfonates are more water-soluble at neutral pH but may show different staining selectivity and diffusion.
  • Versus azo food dyes (e.g., Tartrazine): those are highly water-soluble but differ in spectral properties and tissue affinity.

• Practical tips:

  • Avoid highly acidic, anhydrous conditions for stock solutions if rapid dissolution is required; protic polar solvents accelerate dissolution.
  • Record solvent, concentration, and pH; Martius Yellow shows bathochromic/hyperchromic shifts with pH, which can influence indicator or counterstain performance.

Item-specific solvent specs (solubility numbers, refractive index) are not provided; consult the CoA or determine empirically for your matrix.

Storage & Reconstitution

• Item-specific storage (from Product Data):

  • Storage Conditions: Room temperature.
  • Shipped In: Normal.

• Stability and handling (general/literature):

  • Store tightly capped in a dry, well-ventilated area, protected from excessive heat and direct light to preserve color strength.
  • Avoid prolonged exposure to high humidity; moisture can promote caking and complicate accurate weighing.

• Reconstitution/preparation tips:

  • For stock solutions, dissolve in ethanol, aqueous ethanol, or DMSO. Filter to remove undissolved particulates before use in staining.
  • For aqueous applications, dissolution is enhanced by mild basification (formation of the phenolate); adjust pH to the working range after complete dissolution if compatible with your protocol.
  • Label stock solutions with solvent, concentration, and date. Many dye solutions are stable for weeks at room temperature when protected from light; however, prepare fresh working dilutions frequently to ensure reproducibility.

• Freeze–thaw guidance:

  • Not applicable to dry solid. If storing solutions, avoid repeated freeze–thaw; aliquot if cold storage is necessary.

• Research Use Note (from Product Data): For research use only.

Structure & Identity

Brief description: Martius Yellow is a classical nitroaromatic naphthol dye widely used as a biological/histological counterstain and indicator (literature). Item-specific identifiers are not provided for this catalog entry.

• Item-specific identifiers (from Product Data):

  • CAS: Not specified for this item; refer to CoA/Spec Sheet.
  • InChIKey: Not specified for this item; refer to CoA/Spec Sheet.
  • SMILES: Not specified for this item; refer to CoA/Spec Sheet.
  • Molecular Formula: Not specified for this item; refer to CoA/Spec Sheet.
  • Molecular Weight: Not specified for this item; refer to CoA/Spec Sheet.

• Common literature identity (for context; verify against your lot’s CoA):

  • Common name: Martius Yellow (C.I. 10315)
  • Typical chemical identity: 2,4-dinitro-1-naphthol (literature)
  • Typical molecular formula: C10H6N2O5 (literature)
  • Typical formula weight: ~238.17 g/mol (literature)

• Structural features (literature/general):

  • Aromatic polycyclic core: naphthalene ring system.
  • Functional groups: phenolic hydroxyl (–OH) and two ring-bound nitro groups (–NO2), commonly at the 2- and 4-positions relative to the phenol.
  • Conjugation: strongly conjugated π-system; auxochromic phenolic oxygen and electron-withdrawing nitro groups confer characteristic yellow color.
  • Acid–base behavior: weakly acidic phenolic OH; deprotonation enhances water solubility and causes bathochromic/auxochromic spectral shifts (literature).

• 2D structure description (literature/general):

  • Fused benzene rings (naphthalene) bearing an OH at position 1, with nitro substituents typically at positions 2 and 4 on the same ring; substituent planarity approximates the aromatic plane, with nitro groups slightly twisted due to sterics.

Synthetic Utility

While primarily a histological dye/indicator, Martius Yellow (a nitroaromatic naphthol, literature) possesses functional groups of synthetic interest. These notes are general and not a recommendation to use this SKU for synthesis.

• Functional group leverage (literature/general):

  • Phenolic OH: can undergo O-alkylation/acylation to afford ethers/esters, tuning solubility and spectral properties.
  • Nitro groups: serve as powerful electron-withdrawing substituents; can be reduced (e.g., to amines) under catalytic hydrogenation or metal/acid conditions, potentially enabling access to diamino-naphthol derivatives after appropriate protection of the phenol.
  • Activated aromatic ring: electrophilic substitution is deactivated by nitro groups; nucleophilic aromatic substitution may be possible at positions activated by nitro substitution (substrate-dependent).

• Dye modification (literature):

  • Formation of metal complexes or ion pairs can shift color and solubility; salts of the phenolate enhance water compatibility.
  • Coupling to polymers or surfaces via diazonium strategies typically applies to anilines; for Martius Yellow, derivatization usually proceeds via the phenol or after nitro reduction.

• Retrosynthetic note:

  • Martius Yellow is classically obtained by nitration of 1-naphthol under controlled conditions, leading to regioselective 2,4-dinitration (literature). This informs impurity profiles (mono-/tri-nitrated species) that may influence staining behavior if present.

Target Specificity

No antibody/biomolecule specificity applies. This product is a small-molecule dye/indicator.

• Item-specific data: Not specified for this item; refer to CoA/Spec Sheet.
• General note (literature): In histology, Martius Yellow exhibits preferential staining of erythrocytes and certain fibrin components within multichromatic protocols due to differential dye–tissue interactions. This is not “target specificity” in the immunochemical sense and must be optimized by protocol conditions.