GRADE & PURITYHigh-purity?High-purity grade with substantially reduced impurity levels. Use when trace contaminants would interfere with your measurement or process.≥90%
4-(4-Nitrophenylazo) resorcinol, also known as azo violet or magneson I, is a red colored powder. It functions as a spot test reagent and forms blue lake on reaction with Mg(OH)2 in alkaline solution. It is mainly used for determining the presence of magn
This compound belongs to the class of organic compounds known as azobenzenes. These are organonitrogen aromatic compounds that contain a central azo group, where each nitrogen atom is conjugated to a benzene ring.
External Descriptors
Not available
1. Djoumbou Feunang Y, Eisner R, Knox C, Chepelev L, Hastings J, Owen G, Fahy E, Steinbeck C, Subramanian S, Bolton E, Greiner R, and Wishart DS. ClassyFire: Automated Chemical Classification With A Comprehensive, Computable Taxonomy. Journal of Cheminformatics, 2016, 8:61.
Determine the necessary mass, volume, or concentration for preparing a solution.
Dilution Calculator
Determine the dilution needed to prepare a stock solution.
Reconstitution Calculator
Reviews
Customer Reviews
Application Protocols
Item-specific, tested application parameters are not provided. The following are literature/general protocols to guide method development. Optimize to your system and consult your CoA/SDS.
A. Indicator stock solution (general)
Dissolve Magneson-type dye at 0.1–1.0% (w/v) in ethanol or isopropanol. Protect from light. Filter if particulate is present. Label with date/lot.
B. Visual complexometric titration for Mg2+ (general)
Sample: Aliquot containing Mg2+; adjust to alkaline pH with ammonia/ammonium chloride buffer.
Add 1–2 drops of indicator stock and mix.
Titrate with standardized EDTA until the characteristic endpoint color appears persistently. Perform blanks and spikes to confirm accuracy.
C. Spot test on filter paper (general)
Pre-wet a small area with dilute base.
Add 1–2 drops of indicator solution.
Apply sample; observe for rapid color change compared with a blank area. Use known standards as positive controls.
D. Spectrophotometric assay (general)
Prepare buffered solutions of indicator and analyte at fixed pH.
Record full spectra to identify λmax and isosbestic points; choose an analytical wavelength and construct a calibration curve.
Quality controls
Run blanks, matrix spikes, and independent standards.
Verify that the chosen buffer does not chelate the target metal or precipitate it under test conditions.
Biological Roles
Item-specific biological data
Not specified for this item; refer to CoA/Spec Sheet.
General notes (literature/general)
Magneson-type dyes are synthetic azo compounds designed for analytical chemistry; they do not have known physiological roles and are not endogenous metabolites.
In biological sample analysis, they may be used to visualize or quantify metal ions after appropriate sample preparation, pH adjustment, and masking of interferents. However, matrix effects (proteins, phosphate, citrate) can interfere strongly with metal–indicator equilibria.
No claims are made regarding biocompatibility, toxicity thresholds, or pharmacology. Use strictly for research and laboratory analytical purposes with appropriate containment and waste disposal.
Practical considerations for bioanalytical use
Sample cleanup (e.g., dilution, deproteinization, or chelator removal) is often required before indicator-based assays to avoid false positives/negatives.
Spectral overlap with biological chromophores (heme, flavins) can complicate absorbance measurements; derivative or differential spectrophotometry may be needed for accuracy.
Compliance statement
For research use only. Not for human or animal therapeutic, diagnostic, or clinical applications.
Buffer Applications
Scope
Magneson I is not a buffering agent. However, its indicator performance is pH dependent; thus, buffer selection in analytical procedures is important (literature/general guidance).
Typical buffer systems in metallochromic assays (literature/general)
Ammonia/ammonium chloride (alkaline): Commonly used for Mg2+ and transition-metal complexometric titrations with metallochromic indicators; provides adjustable pH in the 8–11 range.
Borate buffer: Useful for maintaining higher alkaline pH while minimizing metal-chelating background compared with carbonate/bicarbonate.
Carbonate/bicarbonate: Can provide alkaline conditions but may precipitate alkaline earths or alter equilibria; use judiciously.
Practical guidance
Avoid buffers containing strong chelators (citrate, EDTA) that can outcompete the indicator for metal binding unless intentionally used as masking agents.
Verify blank absorbance of the chosen buffer with the indicator at working pH and ionic strength; adjust concentration to minimize background while maintaining pH control.
Metal cleanliness: Use high-purity reagents and deionized water; rinse glassware with dilute acid and water to remove trace metals prior to analysis.
Green Alternatives
Greener handling of metallochromic indicator methods (literature/general)
Solvent substitution: Prefer ethanol or isopropanol over methanol/DMF where possible for preparing indicator stocks; they offer lower toxicity and are derived in part from renewable feedstocks (ethanol).
Aqueous-first approaches: Where solubility allows, use alkaline aqueous media to minimize organic solvent use; prepare the smallest effective indicator concentration.
Microliter-scale assays: Adopt microplate or microspot formats to cut total solvent and dye mass per analysis.
Waste minimization: Segregate metal-containing waste; complexed-metal solutions often drive hazardous classification. Optimize stoichiometry to reduce excess metal and indicator.
Illustrative comparison (general)
Ethanol vs methanol as stock solvent:
Worker safety: Ethanol less acutely toxic than methanol.
Performance: Often similar solvency for azo indicators; verify in your method.
Environmental: Ethanol more favorable in many green metrics.
Aqueous alkaline vs DMSO stocks:
If deprotonated indicator dissolves adequately in base, aqueous systems avoid high-boiling aprotics and simplify waste handling.
Trade-offs
Some indicators require strong solvating media (DMSO/DMF) for concentrated stocks; small volumes and immediate dilution can mitigate environmental and exposure concerns.
Actionable tip
Start with 0.1–0.5% (w/v) in ethanol or 2-propanol, assess stability/lightfastness, and transition to aqueous working media just-in-time to cut solvent footprint.
Pharmaceutical Uses
Item-specific pharmacopeial status/uses
Not specified for this item; refer to CoA/Spec Sheet.
General context (literature/general)
Magneson-type indicator dyes are not pharmaceutical excipients. Their role in pharmaceutical settings, if any, is limited to laboratory analytical procedures (e.g., qualitative/quantitative assays for metal contaminants in raw materials or utilities) performed in QC labs.
No claims are made for therapeutic or diagnostic applications. This product is provided strictly for research and laboratory analysis.
Practical QC notes
If adapting an indicator-based method to GMP environments, ensure the method is validated (specificity, linearity, accuracy, precision, range, robustness) and that indicator identity/purity are documented via CoA and incoming QC testing.
Residual solvents used to dissolve the indicator (e.g., ethanol, isopropanol) should be controlled; prepare fresh solutions and document lot numbers and preparation dates in laboratory records.
Physical Properties
Item-specific values
Appearance: Not specified for this item; refer to CoA/Spec Sheet.
Melting point, boiling point, density, refractive index, pKa, UV/Vis maxima: Not specified for this item; refer to CoA/Spec Sheet.
Solubility: Not specified for this item; refer to CoA/Spec Sheet.
Literature/general expectations for azo metallochromic indicators
Physical state and color: Typically isolated as intensely colored organic solids due to extended azo–aromatic conjugation.
Solubility behavior: Commonly sparingly soluble in water, with improved solubility in polar protic/approtic organic solvents (e.g., ethanol, methanol, acetone, DMF, DMSO). Deprotonation in basic aqueous media often increases solubility through phenolate formation.
Acid–base/color response: Azo/phenol indicators usually show pH-dependent chromism and metal ion–induced bathochromic/hypsochromic shifts, exploited in complexometric and spot-test analyses.
Thermal/light sensitivity: Extended conjugation can be light sensitive; prolonged exposure to strong UV may lead to slow photofading or isomerization in solution (keep solutions protected from light where possible).
Practical guidance
Prepare fresh indicator solutions in alcohol or mixed aqueous–alcohol media for analytical work to minimize oxidative discoloration and baseline drift.
Verify extinction characteristics and working concentration empirically under your specific titration/spot-test conditions.
Quality & Grades
Item-specific quality
Grade/Purity: High-purity (as provided). No additional assay, stabilizer, or impurity limits are specified here; refer to the CoA/Spec Sheet for acceptance criteria.
What “High-purity” means in practice (general guidance)
Intended for analytical/research applications where background absorbance, extraneous coloration, and trace-metal content can affect endpoint sharpness or baseline stability.
For metallochromic indicators, low residual metal content and low inorganic ash are particularly important to avoid pre-complexation and color suppression.
Analytical implications
Batch-to-batch consistency: Key for reproducible color transitions and extinction coefficients in titrations/spot tests.
Users should consult the lot CoA for: assay/purity basis, loss on drying/volatiles, residual metals (if determined), residue on ignition/ash, and any spectroscopic identity checks.
If your method is regulated/validated, consider performing a small qualification set (color transition characterization at working pH, blank absorbance at analytical wavelength, and check of indicator blank titration) with each new lot.
Stabilizers and additives
None specified for this item; refer to CoA/Spec Sheet.
Reaction & Applications
Primary domain (literature/general)
Analytical chemistry: Magneson-type dyes are classical metallochromic indicators for magnesium and other alkaline earth/transition metals. They undergo metal-induced spectral changes (color and absorbance) driven by coordination to deprotonated phenolic/azo donor sites.
Representative applications
Complexometric titrations: Visual endpoints with chelants (e.g., EDTA) in alkaline media; the indicator–metal complex displays a distinct hue that is displaced upon chelation by EDTA.
Spot tests and test papers: Rapid, semi-quantitative detection of Mg2+ and select transition metals on filter paper or TLC plates, often after basification to promote complexation.
Thin-layer visualization: Post-chromatographic detection of certain metal ions via spray reagents prepared from the indicator.
Spectrophotometry: Determination of metals by forming colored complexes and measuring absorbance at a characteristic wavelength; method validation requires calibration and pH control.
Practical tips
pH control is critical: Metal binding and color contrast typically improve in mildly to strongly alkaline ranges. Use metal-free buffers (avoid chelators and high-phosphate loadings) and plasticware/glassware scrupulously cleaned of metal residues.
Indicator concentration: Employ low micromolar to low millimolar working concentrations to avoid self-aggregation and nonspecific background.
Interferences: Competing metal ions, surfactants, and high ionic strength can shift spectra or weaken binding; masking agents (e.g., cyanide, triethanolamine, tartrate—selected with caution and safety) may be used to improve selectivity in validated methods.
Note
For any regulated measurement, confirm exact indicator identity and method parameters per your CoA/SOP before use.
Reaction Conditions
Context
No item-specific kinetic/thermodynamic data are provided. The following summarizes general conditions for indicator-based metal determinations (literature/general guidance).
Indicator: Low concentration of Magneson-type dye in alcohol or aqueous–alcohol; add drops to sample.
Titrant: Standard EDTA solution.
pH: Alkaline conditions favored to deprotonate phenolic groups and enhance metal–indicator color formation.
Endpoint: Distinct color change as metal–indicator complex is displaced by metal–EDTA complex.
Spot test on paper/plate
Reagent: 0.1–1% (w/v) indicator in ethanol or isopropanol; optional mild base to activate color.
Procedure: Apply a small sample aliquot to test paper, add indicator drop, then basify; observe color development.
Spectrophotometric determination
Prepare buffered sample and indicator at fixed pH; record absorbance at the complex’s absorption maximum and construct calibration plots. Verify linear range and potential interferences (competing metals, surfactants).
Practical controls
Use metal-free water/reagents; pre-clean glassware with dilute acid and rinse thoroughly.
Validate selectivity via masking agents if present in the method; confirm absence of precipitation at working pH.
Safety & Handling
Manufacturer hazard information
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 azo indicator dyes (literature/general)
Hazards: Finely divided powders may cause mechanical irritation to eyes/respiratory tract; many azo dyes stain skin and surfaces. Some may be harmful if swallowed or upon prolonged skin contact.
PPE: Use lab coat, safety glasses, and appropriate chemically resistant gloves. Handle powders in a fume hood to reduce dust exposure and inhalation.
Incompatibilities: Avoid strong oxidizers (can bleach/decompose dyes) and strong reducing agents (may reduce –N=N– to amines). Strong acids/bases alter ionization state and color; handle accordingly.
First aid overview: If inhaled—move to fresh air. Eye/skin contact—rinse with water for several minutes; remove contaminated clothing. If ingested—rinse mouth; do not induce vomiting; seek medical attention. Always follow institutional SOPs.
Spills: Avoid dust generation; pick up with damp disposable wipes or HEPA vacuum; wash area with mild detergent.
Waste: Collect dye-containing solutions and contaminated disposables as organic chemical waste per local regulations; complexed metal waste may require specific hazardous waste streams.
Authoritative guidance
Always consult the product-specific SDS for definitive hazard, exposure limits, and emergency measures.
Solvent Selection
Applicability
As a metallochromic indicator/dye, Magneson I is commonly used as a dilute solution rather than as a bulk solvent. Solvent choice determines solubility, stability, and delivery in analytical procedures.
General solvent behavior (literature/general)
Polarity: Azo–aromatic dyes typically dissolve in moderately polar protic (ethanol, methanol, isopropanol) and polar aprotic solvents (acetone, DMF, DMSO); water solubility is often limited unless deprotonated in alkaline media.
Aqueous–alcohol mixtures: Widely used to balance solubility and rapid wetting on test papers/plates; small amounts of base (e.g., NH3, NaOH) can increase solubility by phenolate formation.
Buffer compatibility: For metal-indicator work, avoid buffers containing strong chelating agents (citrate, phosphate at high conc., EDTA) that can compete with metal binding.
When to choose specific media
Ethanol or isopropanol: Good first choices for preparing 0.05–1% (w/v) indicator stocks for spot tests and titrations due to rapid drying and low toxicity relative to methanol (literature/general guidance; confirm in your method).
DMSO or DMF: Useful for concentrated stocks when solubility in alcohols is insufficient; dilute into working aqueous/buffered media just before use.
Alkaline aqueous solutions: Enable direct use in metal-complexation assays where deprotonation enhances color development.
Comparative notes (literature/general)
Compared with other metallochromic indicators (e.g., Eriochrome Black T), solvent needs are similar; however, optimum pH and complexation kinetics may differ—optimize solvent and pH together for your analyte.
Storage & Reconstitution
Manufacturer guidance
Storage conditions: Room temperature (as provided).
Shipped in: Normal (as provided).
General handling recommendations
Keep container tightly closed in a dry, well-ventilated place. Minimize exposure to light to preserve color integrity, particularly for solutions.
Avoid elevated humidity and temperature cycling that can promote clumping or degradation.
Indicator solution handling (literature/general)
Prepare fresh working solutions as needed; azo dye solutions may slowly oxidize or photobleach over time. If prolonged storage is necessary, use amber glass and store at cool room temperature away from direct light.
Do not freeze aqueous–alcohol solutions unless validated for stability.
Reconstitution/solution preparation
If provided as a solid, dissolve in ethanol or isopropanol to prepare a 0.1–1% (w/v) stock as a starting point (optimize concentration for your application). Filter if necessary to remove particulates.
Expiry and QC
No item-specific shelf-life is specified; refer to CoA/Spec Sheet. For critical assays, re-verify performance (color response, blank absorbance) after any prolonged storage or upon opening a new lot.
Research use
For research use only.
Structure & Identity
SKU: M110710
Product name: Magneson I
CAS: 74-39-5 (as provided in product data)
PubChem CID: 6320 (as provided in product data)
InChIKey: 238025 (as provided in product data)
Item-specific identifiers
Molecular formula: Not specified for this item; refer to CoA/Spec Sheet.
Molecular weight: Not specified for this item; refer to CoA/Spec Sheet.
SMILES: Not specified for this item; refer to CoA/Spec Sheet.
General structural features (literature/general)
Magneson I is historically described as an azo dye–type metallochromic indicator used for Mg2+ detection/visualization. Azo indicators typically contain an –N=N– azo linkage conjugated to phenolic or naphtholic rings that provide metal-chelating o,o′-dihydroxy (or hydroxy/aza) donor sets.
The conjugated aromatic framework underpins vivid coloration and pH-dependent tautomerism (azo/quinone-hydrazone), which can be perturbed by metal binding to afford distinct color changes.
2D structural description (literature/general)
Planar, extended π-system comprising fused/aromatic rings bridged by an azo unit.
Phenolic OH substituents capable of deprotonation in alkaline media to generate an anionic chromophore that coordinates divalent cations (e.g., Mg2+) through O,O′-donation.
Notes
Where precise identifiers (formula, MW, definitive structure) are required for regulatory or analytical purposes, consult the product’s CoA/Specification Sheet and SDS.
Synthetic Utility
Applicability
As supplied, Magneson I functions primarily as an analytical reagent rather than a synthetic intermediate. No item-specific reactivity data are provided.
Literature/general reactivity of azo–phenol systems
Chelating ligands: Azo–phenol frameworks can act as O,O′-donor bidentate ligands to form stable complexes with Mg2+, Cu2+, Ni2+, Co2+, etc. Isolated metal complexes are studied for coordination chemistry and materials coloration.
Tautomerism: Azo/quinone–hydrazone tautomerism influences acidity, metal binding, and spectral properties—relevant when designing derivatives or immobilizing the dye on polymers/silica.
Derivatization: Electrophilic aromatic substitution (sulfonation, nitration) and azo-coupling modifications can be used to tune solubility and metal specificity, forming a family of indicators.
Use cases in method development
Immobilization: Covalent or adsorptive attachment to cellulose, silica gel, or polymer membranes enables solid-phase tests and sensor strips for Mg2+ and related metals.
Polymer incorporation: Coating or doping in ion-selective membranes can create colorimetric sensing elements.
Note
If using this product as a ligand precursor or for materials synthesis, confirm structural details and purity specifications on the CoA; optimize reaction conditions empirically.
Target Specificity
Not applicable.
This product is a small-molecule indicator dye, not a biological affinity reagent. No antibody/epitope/clone/isotype information applies.
For metal-ion selectivity in analytical chemistry, consult the Reaction & Applications and Reaction Conditions tabs (literature/general guidance) and validate selectivity under your matrix and pH.
Need help choosing the grade?
Our grade selection guide covers purity, stabilizer status, and application suitability for all variants in our catalog.
We use cookies to ensure the website functions properly and, where permitted, to improve your experience. You can manage your preferences at any time in Settings. Learn more in our Cookie Policy.
Shall we send you a message when we have discounts available?
Remind me later
Thank you! Please check your email inbox to confirm.
Products are supplied to verified businesses, institutions, and qualified professionals for research and development use only. Not for use in humans, animals, diagnosis, or therapy.
F2404364