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Dichloran | 2,6-Dichloro-4-nitroaniline ASA-2057
$25.00 AUD
Dichloran — Selective Fungal Media Reagent
The key additive for DRBC Agar and DG18 Agar. Restricts fast-spreading moulds so your yeast and mould plates are readable, countable, and defensible.
Cat. No. ASA-2057 CAS 99-30-9 C₆H₄Cl₂N₂O₂ MW 207.01 g/mol ≥98.0% Purity (HPLC) ✓ ISO 21527 Compatible 🇦🇺 Made in Melbourne ⚡ Same-Week Dispatch
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Full DocumentationCOA, TDS & SDS with every batch🇦🇺
Australian StockNo import delays or customs holdups⚡
Same-Week DispatchMelbourne warehouse — fast turnaround🔬
Technical SupportDirect from our microbiology teamWhat Is Dichloran & Why Does It Matter?
Dichloran (2,6-Dichloro-4-nitroaniline, DCNA) is a selective fungicide used as a media additive specifically to control colony spread of fast-growing moulds — particularly Mucor, Rhizopus, and Mortierella spp. — that would otherwise overgrow plates and prevent accurate enumeration of slower-growing yeasts and other fungi.
Without dichloran, a single Mucor colony on a plate can spread across the entire surface within 24 hours, obscuring all other colonies and making the count scientifically meaningless. At the validated concentration of 2 mg/L in DRBC Agar and 2 mg/L in DG18 Agar, dichloran selectively inhibits hyphal spreading without significantly reducing the recovery of target yeasts and slower-growing moulds.
Mode of Action
Hyphal Growth Restriction → Plate Readability → Accurate Enumeration
Dichloran is a contact fungicide that interferes with spore germination and hyphal elongation in susceptible fast-spreading mould species. Its mechanism involves disruption of membrane sterol biosynthesis and cell wall integrity in Mucorales-class fungi. At the low concentrations used in DRBC and DG18 Agar (2 mg/L), it does not completely inhibit growth of these organisms — rather, it restricts the radial spread of colonies, keeping them compact and countable. Target organisms (yeasts, Aspergillus, Penicillium, xerophilic moulds) are less sensitive at these concentrations and grow normally.
Dichloran is a contact fungicide that interferes with spore germination and hyphal elongation in susceptible fast-spreading mould species. Its mechanism involves disruption of membrane sterol biosynthesis and cell wall integrity in Mucorales-class fungi. At the low concentrations used in DRBC and DG18 Agar (2 mg/L), it does not completely inhibit growth of these organisms — rather, it restricts the radial spread of colonies, keeping them compact and countable. Target organisms (yeasts, Aspergillus, Penicillium, xerophilic moulds) are less sensitive at these concentrations and grow normally.
Primary Applications
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Food Microbiology
ISO 21527-1 & -2 workflows
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Beverage QC
Yeast & mould enumeration
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Environmental
Air & surface sampling
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Industrial QC
Cosmetics & pharma
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Research
Custom media preparation
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Education
Teaching & demonstration
How to Use Dichloran — DRBC Agar Preparation
ⓘ Standard use level: 2 mg/L in final agar. Prepare a stock solution for accurate dosing.
| 1 | Prepare dichloran stock solution: Dissolve 0.2 g Dichloran (ASA-2057) in 100 mL of 95% ethanol to make a 2 mg/mL stock. Filter-sterilise (0.22 µm) or prepare fresh before use. Store at 4°C in dark. |
| 2 | Prepare base agar: Weigh and dissolve the remaining DRBC Agar components (peptone, dextrose, KH₂PO₄, MgSO₄, Rose Bengal, Chloramphenicol, Agar) in distilled water per your validated SOP. Autoclave at 121°C / 15 min. |
| 3 | Add dichloran: Cool autoclaved base to 45–50°C. Add 1 mL of stock solution per litre of agar (final concentration = 2 mg/L). Mix gently. |
| 4 | Pour plates: Pour immediately (~20 mL per 90 mm plate). Allow to solidify on a level surface. Dry at 37°C / 30 min lids ajar. Store at 2–8°C in sealed bags, protected from light. |
| 5 | Inoculate & incubate: Spread-plate or pour-plate sample. Incubate at 25°C for 5 days (ISO 21527-1). Count colonies. Fast-spreading moulds will appear compact and enumerable. |
⚠️ Use dichloran only in validated media formulations (DRBC, DG18) at the specified 2 mg/L concentration. Higher concentrations may inhibit recovery of target fungi. Always prepare fresh stock solutions; dichloran in ethanol is stable 1 month at 4°C in the dark.
Dichloran-Based Media — Comparison
| Medium | Dichloran Conc. | Target Organisms | Application | ISO Reference |
|---|---|---|---|---|
|
DRBC Agar (Dichloran Rose Bengal Chloramphenicol) |
2 mg/L | Yeasts & moulds (mesophilic) | Food, beverage, environmental — general YM count | ISO 21527-1:2008 |
|
DG18 Agar (Dichloran Glycerol Sorbitol) |
2 mg/L | Xerophilic & xerotolerant moulds | Low water activity foods (nuts, spices, dried fruit, grains) | ISO 21527-2:2008 |
|
DA Agar (Dichloran Agar — research use) |
2 mg/L | General spreading moulds | Experimental / custom media formulations | Research literature |
DRBC vs DG18 — Which Should You Use?
| Factor | DRBC Agar | DG18 Agar |
|---|---|---|
| Water activity (aᴜ) | ~0.993 (standard) | ~0.955 (reduced) |
| Target fungi | Mesophilic yeasts & moulds | Xerophilic & xerotolerant moulds |
| Food applications | Fresh produce, dairy, meat, beverages | Dried fruit, nuts, spices, grains, flour |
| Incubation | 25°C / 5 days | 25°C / 5 days |
| ISO standard | ISO 21527-1:2008 | ISO 21527-2:2008 |
| Dichloran role | Restricts Mucorales spreading | Restricts Mucorales spreading |
ⓘ Quick rule: Use DRBC for most food and environmental samples. Use DG18 when testing low water activity products (nuts, dried herbs, spices, grains, confectionery). Both require dichloran at 2 mg/L.
Frequently Asked Questions
Can I use dichloran directly in agar without making a stock solution?
Not recommended. Dichloran has very low water solubility (~6 mg/L at 25°C). Preparing a 2 mg/mL stock in 95% ethanol and adding 1 mL/L ensures accurate, homogeneous distribution at the validated 2 mg/L concentration.
Does dichloran inhibit yeasts?
At 2 mg/L, dichloran does not significantly inhibit yeast growth. It selectively targets fast-spreading Mucorales (Mucor, Rhizopus) at this concentration, while yeasts (Candida, Saccharomyces) and slower-growing moulds (Aspergillus, Penicillium) are not substantially affected.
What makes DRBC different from Rose Bengal Chloramphenicol (RBC) Agar?
RBC Agar uses Rose Bengal alone to restrict colony spreading. DRBC adds dichloran specifically to further restrict fast-spreading Mucorales that Rose Bengal alone does not adequately control. ISO 21527-1 recommends DRBC over RBC for this reason.
How long is the dichloran stock solution stable?
Dichloran dissolved in 95% ethanol is stable for approximately 1 month when stored at 2–8°C in a dark, sealed container. Prepare fresh if colour changes or precipitate forms. The dry powder is stable for 3+ years under recommended storage conditions.
Is AuSaMicS Dichloran equivalent to Sigma-Aldrich D130605?
Yes. AuSaMicS ASA-2057 is CAS 99-30-9, ≥98.0% purity — equivalent in specification to Sigma-Aldrich D130605, Merck 8.42404, and Thermo Fisher A13884. Full COA available with every batch for side-by-side comparison.
Cross-Reference / Equivalent Products
| Manufacturer | Product Name | Cat. No. | Notes |
|---|---|---|---|
| Sigma-Aldrich (Merck) | Dichloran | D130605 | Equivalent purity grade |
| Merck Millipore | Dichloran for synthesis | 8.42404 | Equivalent grade |
| Thermo Fisher Scientific | 2,6-Dichloro-4-nitroaniline | A13884 | Equivalent grade |
| AK Scientific | Dichloran | X3279 | Equivalent grade |
AuSaMicS ASA-2057 is manufactured locally in Melbourne — same-week dispatch, no import delays, COA included.
Related Products
Chemical & Physical Properties
| Product Name | Dichloran |
| Catalogue Number | ASA-2057 |
| IUPAC Name | 2,6-Dichloro-4-nitroaniline |
| Synonyms | DCNA; 4-Nitro-2,6-dichloroaniline; Botran® (technical grade pesticide, not this product) |
| CAS Number | 99-30-9 |
| Molecular Formula | C₆H₄Cl₂N₂O₂ |
| Molecular Weight | 207.01 g/mol |
| Grade | Laboratory Grade |
| Purity | ≥98.0% (HPLC) |
| Appearance | Yellow to pale yellow crystalline powder |
| Melting Point | 195–196°C |
| Solubility (water) | ~6 mg/L at 25°C (very slightly soluble) |
| Solubility (ethanol) | ~2 g/100 mL in 95% ethanol (use for stock prep) |
| Solubility (acetone) | Soluble |
| λmax | ~370 nm (in ethanol) |
Validated Use Levels
| Medium | Final Concentration | Stock Addition | ISO Reference |
|---|---|---|---|
| DRBC Agar | 2 mg/L (2 ppm) | 1 mL of 2 mg/mL ethanol stock per litre | ISO 21527-1:2008 |
| DG18 Agar | 2 mg/L (2 ppm) | 1 mL of 2 mg/mL ethanol stock per litre | ISO 21527-2:2008 |
| Research media | 1–5 mg/L (validated) | Per internal SOP | Literature / SOP |
Stock Solution Preparation
| Standard Stock | 0.2 g Dichloran in 100 mL 95% ethanol = 2 mg/mL |
| Addition rate | 1 mL stock per litre of agar (after autoclaving, ≤50°C) = 2 mg/L final |
| Sterilisation | Filter-sterilise stock (0.22 µm PTFE membrane); do NOT autoclave the stock solution |
| Stock stability | 1 month at 2–8°C in sealed dark container |
| Agar addition temp | ≤50°C (cool autoclaved agar before adding stock) |
Storage & Stability
| Storage Temperature | 2–8°C (refrigerator); protect from heat and light |
| Container | Tightly sealed, amber glass or light-resistant container |
| Protect From | Heat above 40°C, direct sunlight, moisture |
| Shelf Life (powder) | 3 years from manufacture date under correct storage |
Literature & References
| # | Reference |
|---|---|
| 1 | Jarvis B, Williams AP. Methods for detecting fungi in foods and feeds. J Assoc Off Anal Chem. 1987;70(5):774–789. [Original DRBC Agar validation with dichloran] |
| 2 | International Organization for Standardization. ISO 21527-1:2008. Food and animal feeding stuffs — Horizontal method for the enumeration of yeasts and moulds — Part 1: Colony count technique in products with water activity greater than 0.95. Geneva: ISO; 2008. |
| 3 | International Organization for Standardization. ISO 21527-2:2008. Food and animal feeding stuffs — Part 2: Colony count technique in products with water activity less than or equal to 0.95. Geneva: ISO; 2008. |
| 4 | King AD, Hocking AD, Pitt JI. Dichloran-rose bengal medium for enumeration and isolation of molds from foods. Appl Environ Microbiol. 1979;37(5):959–964. [Original DRBC Agar paper] |
| 5 | Hocking AD, Pitt JI. Dichloran-glycerol medium for enumeration of xerophilic fungi from low-moisture foods. Appl Environ Microbiol. 1980;39(3):488–492. [Original DG18 Agar paper] |
📄 Full SDS available: 16-section GHS SDS (Australian WHS Regulations 2023 / GHS 7th Edition) — contact support@ausamics.com.au
Section 1 — Identification
| Product Name | Dichloran |
| Catalogue No. | ASA-2057 |
| 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 | Acute Tox. 4 (oral) — H302: Harmful if swallowed Skin Irrit. 2 — H315: Causes skin irritation Eye Irrit. 2 — H319: Causes serious eye irritation Repr. 2 — H361: Suspected of damaging fertility or the unborn child Aquatic Chronic 3 — H412: Harmful to aquatic life with long-lasting effects |
| Signal Word | WARNING |
| GHS Pictograms | ⚠️ Exclamation mark | ☣️ Health hazard | 🌿 Environmental hazard |
Sections 4–8 — First Aid, Fire & PPE
| Inhalation | Remove to fresh air. Seek medical attention if symptoms persist. Avoid generating dust. |
| Skin Contact | Remove contaminated clothing. Wash with soap and water ≥15 min. Seek advice if irritation develops. |
| Eye Contact | Irrigate with water ≥15 min, hold eyelids apart. Seek immediate medical attention. |
| Ingestion | Do NOT induce vomiting. Rinse mouth. Call Poisons Centre 13 11 26. Seek medical attention. |
| Extinguishing Media | Water spray, foam, dry powder, CO₂ |
| Respiratory Protection | P2 particulate filter when weighing or handling bulk powder |
| Eye Protection | Safety glasses or chemical splash goggles |
| Skin Protection | Nitrile gloves (≥0.11 mm), lab coat, closed footwear |
⚠️ Reproductive Hazard (H361): Suspected of damaging fertility or the unborn child. Female employees of childbearing age should assess exposure risk with occupational health advisor before handling. At the very low concentrations used in prepared media (2 mg/L), risk is expected to be minimal — however, apply standard laboratory PPE.
Sections 12–15 — Ecology, Disposal & Regulatory
| Aquatic Toxicity | Harmful to aquatic life with long lasting effects (H412). Do not discharge to waterways or drains. |
| Disposal | Dispose as chemical waste via licensed contractor per local EPA regulations. Do not drain-dispose even small quantities. |
| Transport | Not classified as dangerous goods — ADG Code (Australia), IMDG, IATA at laboratory pack sizes |
| Regulatory Framework | Australian WHS Regulations 2023 | GHS 7th Edition | Safe Work Australia COP 2021 |
| AICIS Status | Listed on Australian Inventory of Industrial Chemicals (AIIC) |
| SUSMP Schedule | Not scheduled for laboratory reagent quantities |
| Agricultural Use | Dichloran is a registered agricultural fungicide (Botran®) — this product (ASA-2057) is laboratory reagent grade ONLY, not for agricultural use |
Quality Specifications
| Parameter | Specification | Method |
|---|---|---|
| Appearance | Yellow to pale yellow crystalline powder; free-flowing | Visual |
| Purity | ≥98.0% | HPLC |
| Melting Point | 195–196°C | DSC / capillary method |
| Loss on Drying | ≤1.0% | Loss on drying (105°C / 2h) |
| Identity | Consistent with reference IR spectrum (CAS 99-30-9) | IR spectroscopy |
| Heavy Metals | ≤20 ppm | ICP-OES |
| Functional Performance | Restricts colony spread of Mucor circinelloides in DRBC Agar at 2 mg/L | Plate assay |
| Batch COA | Available for every production lot | On request or download |
Manufacturing & Documentation
Supplied by AuSaMicS Pty Ltd
31 Longview CT, Thomastown VIC 3074, Australia | ABN 56 676 640 467
✓ Batch-level quality control with HPLC purity verification
✓ Full GHS-compliant documentation (COA, TDS, SDS) with every order
✓ Australian stock — no import delays, no customs clearance
✓ Technical support from our microbiology team (media preparation guidance available)
✓ 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
✓ Batch-level quality control with HPLC purity verification
✓ Full GHS-compliant documentation (COA, TDS, SDS) with every order
✓ Australian stock — no import delays, no customs clearance
✓ Technical support from our microbiology team (media preparation guidance available)
✓ Available in 1 g, 5 g, 10 g, 25 g, 100 g pack sizes
Available Documentation
| 📄 Certificate of Analysis (COA) | Batch-specific | Included with every order |
| 📋 Technical Data Sheet (TDS) | Full specifications, stock prep protocol, use levels |
| ⚠️ Safety Data Sheet (SDS) | GHS 7th Ed | WHS 2023 compliant | 16 sections | Includes H361 reproductive hazard notice |
⚠️ Intended Use: For laboratory, research, and industrial QC use only. Not for agricultural, food, human, veterinary, or therapeutic use. This product contains a reproductive hazard (H361) — handle with appropriate PPE and risk assessment.