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Resazurin Sodium Salt l ASD-622
$49.00 AUD
Resazurin Sodium Salt
Redox indicator for anaerobic culture media, microbial viability assays, AlamarBlue-type cell metabolic activity, and antibiotic susceptibility testing. Blue → Pink → Colourless on reduction.
Cat. No. ASD-622 CAS 62758-13-8 C₁₂H₆NNaO₄ MW 251.17 g/mol ≥98.0% Purity AlamarBlue Equivalent 🇦🇺 Made in Melbourne ⚡ Same-Week Dispatch
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Full DocumentationCOA, TDS & SDS included🇦🇺
Australian StockNo import delays⚡
Same-Week DispatchMelbourne warehouse🔬
Technical SupportDirect from our teamWhat Is Resazurin & How Does the Colour Change Work?
Resazurin Sodium Salt is a phenoxazine redox indicator dye that undergoes a well-defined, visually striking colour change in response to cellular metabolic activity and reducing conditions. It is one of the most versatile indicators in microbiology and cell biology — used as an anaerobic media indicator, a viability dye, and a metabolic activity reporter.
Colour Change Cascade
🟧 Blue
Resazurin (oxidised)
Non-fluorescent
Non-fluorescent
→
🥢 Pink / Red
Resorufin (reduced)
Fluorescent λᴇm ~590 nm
Fluorescent λᴇm ~590 nm
→
◯ Colourless
Dihydroresorufin (fully reduced)
Non-fluorescent
Non-fluorescent
Colour change is irreversible in the first step (resazurin → resorufin) and reversible in the second (resorufin ⇌ dihydroresorufin).
Mode of Action
Oxidation-Reduction (Redox) Indicator → Metabolic Activity Reporter
Resazurin (blue, oxidised form) is reduced to resorufin (pink/red, fluorescent) by cellular reductants — primarily NADH, NADPH, and the flavoenzymes of the electron transport chain in metabolically active cells. This reduction reflects cellular metabolic activity and is proportional to the number of viable, metabolically active cells. The resorufin product can be further reduced to the colourless, non-fluorescent dihydroresorufin by highly reduced environments or dense cell populations.
In anaerobic media, resazurin serves as an anaerobiosis indicator — the medium turns from blue/purple (oxidised) to pink/colourless (reduced) as oxygen is consumed, confirming that anaerobic conditions have been achieved. Re-oxygenation causes the medium to return to blue (the reaction is partially reversible).
Resazurin (blue, oxidised form) is reduced to resorufin (pink/red, fluorescent) by cellular reductants — primarily NADH, NADPH, and the flavoenzymes of the electron transport chain in metabolically active cells. This reduction reflects cellular metabolic activity and is proportional to the number of viable, metabolically active cells. The resorufin product can be further reduced to the colourless, non-fluorescent dihydroresorufin by highly reduced environments or dense cell populations.
In anaerobic media, resazurin serves as an anaerobiosis indicator — the medium turns from blue/purple (oxidised) to pink/colourless (reduced) as oxygen is consumed, confirming that anaerobic conditions have been achieved. Re-oxygenation causes the medium to return to blue (the reaction is partially reversible).
Applications
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Anaerobic Media
Anaerobiosis indicator in broths & agars
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Viability Assays
AlamarBlue-type microbial & cell viability
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REMA / MABA
TB antibiotic susceptibility testing
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Biofilm Assays
Metabolic activity of biofilm biomass
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Milk Quality
Reductase test for milk freshness
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Education
Redox & metabolism demonstrations
Key Application Protocols
1. Anaerobic Media Indicator
| 1 | Prepare stock solution: Dissolve 0.1 g Resazurin Sodium Salt (ASD-622) in 100 mL sterile distilled water (1 mg/mL stock). Protect from light. Store at 4°C. |
| 2 | Add to medium: Add 1 mL of stock per litre of anaerobic broth or agar after autoclaving (≤50°C). Final concentration: 1 mg/L (1 ppm). Mix gently. |
| 3 | Interpret: Blue/purple = oxidised (aerobic — do not inoculate). Pink or colourless = reduced (anaerobic conditions achieved — safe to inoculate). Discard or re-reduce if medium re-oxidises before use. |
2. AlamarBlue-Type Microbial Viability Assay
| 1 | Prepare working solution: Dilute stock to 0.01% w/v (100 µg/mL) in sterile PBS or culture medium. Filter-sterilise (0.22 µm). |
| 2 | Add to cell/microbial suspension: Add resazurin working solution to wells containing organisms at 10% v/v final concentration. Incubate at 37°C (bacteria) or 30°C (yeasts). |
| 3 | Read: Measure fluorescence (Ex 560 nm / Em 590 nm) or absorbance (570 nm vs 600 nm reference) at 1–4 h intervals. Viable, metabolically active cells reduce resazurin → resorufin → fluorescence increase proportional to cell number. |
| 4 | Antibiotic susceptibility (REMA/MABA): Inoculate test organism into antibiotic dilution series in 96-well plate. Add resazurin at 0.002% final concentration. Incubate 5–7 days (Mtb) or 24–48h (rapid growers). Pink = growth (resistant). Blue = inhibited (susceptible). MIC = lowest concentration maintaining blue colour. |
⚠️ Protect resazurin solutions from unnecessary light exposure — photooxidation can cause false background reduction. Prepare fresh working solutions where high assay sensitivity is required.
Resazurin vs Other Redox / Viability Indicators
| Indicator | Redox Change | Fluorescent? | Primary Use |
|---|---|---|---|
| Resazurin (ASD-622) | Blue → Pink → Colourless | Yes (resorufin, 590 nm) | Anaerobic media; viability; REMA/MABA; milk testing |
| Methylene Blue (ASD-601) | Blue → Colourless (leucoform) | No | Redox indicator; bacterial staining; RNA gels |
| Neutral Red | Red → Yellow (pH dependent) | No | pH indicator in media; cell staining |
| MTT | Yellow → Purple (formazan) | No | Cell viability (requires solubilisation step) |
| XTT | Orange → Red | No | Cell viability (soluble product, no wash step) |
Frequently Asked Questions
Is AuSaMicS Resazurin (ASA-2059) equivalent to AlamarBlue?
AlamarBlue (now BioLegend) is a proprietary formulation whose active ingredient is resazurin sodium salt. ASA-2059 is the same compound (CAS 62758-13-8) at ≥98.0% purity. Resazurin sodium salt in aqueous solution at 0.01–0.1% is functionally equivalent to AlamarBlue and is used in the same assay formats at significantly lower cost.
At what concentration is resazurin used in anaerobic media?
Typically 1 mg/L (1 ppm) in the final prepared medium — add 1 mL of a 1 mg/mL aqueous stock per litre. This concentration gives a clear visual blue → pink colour change without significantly affecting organism growth. Some formulations use 0.5–2 mg/L depending on the medium and application.
What is REMA/MABA and why does it use resazurin?
REMA (Resazurin Microtitre Assay) and MABA (Microplate Alamar Blue Assay) are rapid, low-cost 96-well plate methods for determining the minimum inhibitory concentration (MIC) of antibiotics against Mycobacterium tuberculosis and other slow-growing pathogens. Resazurin is the viability reporter — metabolically active (resistant) organisms reduce it to pink resorufin, while inhibited (susceptible) wells remain blue. Results are read visually or fluorimetrically within 5–7 days, compared to 3–4 weeks for conventional solid media methods.
Can resazurin be autoclaved?
No — resazurin stock solutions should NOT be autoclaved. Prepare as an aqueous stock, filter-sterilise (0.22 µm), and add aseptically to cooled sterile media (<50°C). The dry powder is heat-stable; only aqueous solutions are sensitive.
Is CAS 62758-13-8 the correct number for resazurin sodium salt?
Yes. CAS 62758-13-8 is the sodium salt form (resazurin sodium salt, MW 251.17). The free acid form of resazurin has CAS 550-82-3 (MW 229.19). AuSaMicS ASA-2059 is the sodium salt (water-soluble form), which is the standard laboratory grade.
Cross-Reference / Equivalent Products
| Manufacturer | Product Name | Cat. No. | Notes |
|---|---|---|---|
| Sigma-Aldrich (Merck) | Resazurin sodium salt | R7017 | Equivalent grade; CAS 62758-13-8 |
| Merck Millipore | Resazurin sodium salt | 1.01605 | Equivalent grade |
| Thermo Fisher Scientific | Resazurin, Sodium Salt | R12204 | Equivalent grade |
| BioLegend (ThermoFisher) | AlamarBlue® Cell Viability Reagent | DAL1025 | Proprietary formulation; active ingredient = resazurin |
AuSaMicS ASA-2059 is supplied locally in Melbourne at significantly lower cost than proprietary AlamarBlue formulations — same compound, same performance.
Related Products
Chemical & Physical Properties
| Product Name | Resazurin Sodium Salt |
| Catalogue Number | ASA-2059 |
| IUPAC Name | Sodium 7-hydroxy-3H-phenoxazin-3-one 10-oxide |
| Synonyms | Resazurin sodium; Diazoresorcinol sodium; AlamarBlue active component; CI 51010 |
| CAS Number (sodium salt) | 62758-13-8 |
| CAS Number (free acid) | 550-82-3 (not this product) |
| Molecular Formula | C₁₂H₆NNaO₄ |
| Molecular Weight | 251.17 g/mol |
| Grade | Laboratory Grade |
| Purity | ≥98.0% |
| Appearance | Dark green to brownish-purple crystalline powder with metallic lustre |
| Solution colour (oxidised) | Blue (dilute aqueous solution) |
| Reduction product | Resorufin (pink/red, fluorescent; λex ~560 nm / λem ~590 nm) |
| Solubility (water) | Freely soluble — ~3.5 g/100 mL at 25°C |
| Solubility (ethanol) | Slightly soluble |
| λmax (aqueous, oxidised) | ~600 nm (blue/violet) |
| Fluorescence (resorufin) | λex 560 nm / λem 590 nm |
Working Concentrations by Application
| Application | Working Concentration | Detection | Notes |
|---|---|---|---|
| Anaerobic media indicator | 0.5–1 mg/L (0.5–1 ppm) | Visual (blue → pink) | Add as aqueous stock post-autoclave |
| Microbial viability assay | 0.002–0.01% w/v | Fluorescence or colorimetric | 10% v/v of 0.02–0.1 mg/mL working solution |
| REMA / MABA (TB MIC) | 0.002% w/v final | Visual (blue = inhibited) | Add 20µL of 0.02% to 96-well plates |
| Milk reductase test | ~0.005–0.01% w/v | Visual (blue → colourless) | Time to decolourisation indicates microbial load |
Storage & Stability
| Storage Temperature | 2–8°C; protect from light |
| Container | Tightly sealed, amber or light-resistant container |
| Protect From | Direct light (photosensitive), heat above 40°C, moisture |
| Shelf Life (powder) | ≥3 years from manufacture date |
| Aqueous Stock (1 mg/mL) | Stable 1–3 months at 4°C in dark. Discard if colour changes significantly or precipitate forms. |
Literature & References
| # | Reference |
|---|---|
| 1 | O'Brien J, et al. Investigation of the Alamar Blue (resazurin) fluorescent dye for the assessment of mammalian cell cytotoxicity. Eur J Biochem. 2000;267(17):5421–5426. [Mechanism of resazurin reduction in cell viability assays] |
| 2 | Palomino JC, et al. Resazurin Microtiter Assay Plate: simple and inexpensive method for detection of drug resistance in Mycobacterium tuberculosis. Antimicrob Agents Chemother. 2002;46(8):2720–2722. [Original REMA method paper] |
| 3 | Collins L, Franzblau SG. Microplate alamar blue assay versus BACTEC 460 system for high-throughput screening of compounds against Mycobacterium tuberculosis and Mycobacterium avium. Antimicrob Agents Chemother. 1997;41(5):1004–1009. [MABA method development] |
| 4 | Nakayama GR, et al. Assessment of the Alamar Blue assay for cellular growth and viability in vitro. J Immunol Methods. 1997;204(2):205–208. [Resazurin viability assay validation] |
| 5 | ISO 11283:1997. Microbiology of food and animal feeding stuffs — Horizontal method for the enumeration of β-glucuronidase-positive Escherichia coli. [References resazurin in anaerobic media context] |
📄 Full SDS available: 16-section GHS SDS (Australian WHS Regulations 2023 / GHS 7th Edition) — support@ausamics.com.au
Section 1 — Identification
| Product Name | Resazurin Sodium Salt |
| Catalogue No. | ASA-2059 |
| Supplier | AuSaMicS Pty Ltd | ABN 56 676 640 467 |
| Address | 31 Longview CT, Thomastown VIC 3074, Australia |
| Emergency | Poisons Information Centre: 13 11 26 (24 hr) |
| Phone | +61 412 520 598 |
| support@ausamics.com.au |
Section 2 — Hazard Identification (GHS 7th Ed / WHS 2023)
| GHS Classification | Eye Irrit. 2 — H319: Causes serious eye irritation Aquatic Chronic 3 — H412: Harmful to aquatic life with long-lasting effects |
| Signal Word | WARNING |
| GHS Pictograms | ⚠️ Exclamation mark | 🌿 Environmental hazard |
| Note | Relatively low hazard profile at laboratory use concentrations. Primary concern is eye irritation and aquatic toxicity. |
Sections 4–8 — First Aid, Fire & PPE
| Inhalation | Remove to fresh air. Seek medical attention if symptoms persist. |
| Skin Contact | Wash with soap and water. Note: may stain skin pink/purple — not a hazard, fades within hours. |
| Eye Contact | Irrigate immediately with water ≥15 min, hold eyelids apart. Seek medical attention if irritation persists. |
| Ingestion | Rinse mouth. Not expected to be acutely toxic at laboratory quantities. Call Poisons Centre 13 11 26 if large amounts ingested. |
| Extinguishing Media | Water spray, foam, dry powder, CO₂ |
| Respiratory Protection | P1 filter when weighing bulk powder |
| Eye Protection | Safety glasses — eye staining risk from solutions |
| Skin Protection | Nitrile gloves, lab coat. Resazurin stains skin and clothing — use disposable gloves. |
Sections 12–15 — Ecology, Disposal & Regulatory
| Aquatic Toxicity | Harmful to aquatic life with long-lasting effects (H412). Avoid bulk discharge to waterways. |
| Disposal | Dispose of solutions as chemical waste per local EPA regulations. Small volumes may be diluted and disposed via trade waste drain per institutional policy. |
| Transport | Not classified as dangerous goods — ADG, IMDG, IATA |
| Regulatory Framework | Australian WHS Regulations 2023 | GHS 7th Edition | Safe Work Australia COP 2021 |
| AICIS Status | Listed on Australian Inventory of Industrial Chemicals (AIIC) |
| Poisons Schedule | Not scheduled under SUSMP |
Quality Specifications
| Parameter | Specification | Method |
|---|---|---|
| Appearance | Dark green to brownish-purple crystalline powder with metallic lustre | Visual |
| Purity | ≥98.0% | HPLC |
| λmax (aqueous, oxidised) | 600 ± 5 nm | UV-Vis spectrophotometry |
| Water Solubility | Complete dissolution in water at 3.5 g/100 mL; blue solution | Visual inspection |
| Redox Response | Colour change blue → pink on addition of ascorbic acid (reducing agent) — confirms active redox indicator function | Functional redox test |
| Loss on Drying | ≤2.0% | Loss on drying (60°C / 2h) |
| Heavy Metals | ≤20 ppm | ICP-OES |
| Batch COA | Available for every production lot | On request or included |
Manufacturing & Documentation
Supplied by AuSaMicS Pty Ltd
31 Longview CT, Thomastown VIC 3074, Australia | ABN 56 676 640 467
✓ HPLC purity verification and functional redox test per batch
✓ COA, TDS, SDS included with every order
✓ Australian stock — no import delays
✓ Cost-effective alternative to proprietary AlamarBlue formulations
✓ Available in 1 g, 5 g, 10 g, 25 g, 100 g pack sizes
31 Longview CT, Thomastown VIC 3074, Australia | ABN 56 676 640 467
✓ HPLC purity verification and functional redox test per batch
✓ COA, TDS, SDS included with every order
✓ Australian stock — no import delays
✓ Cost-effective alternative to proprietary AlamarBlue formulations
✓ Available in 1 g, 5 g, 10 g, 25 g, 100 g pack sizes
⚠️ Intended Use: For laboratory and research use only. Not for therapeutic, diagnostic, food, veterinary, or consumer use. Photosensitive — store and use protected from unnecessary light exposure.