If this product has an expiration or retest date, it will be shown on the Certificate of Analysis (COA, CofA). If there is no retest or expiration date listed on the product's COA, we do not have suitable stability data to determine a shelf life. For these products, the only date on the COA will be the release date; a retest, expiration, or use-by-date will not be displayed.
For all products, we recommend handling per defined conditions as printed in our product literature and website product descriptions. We recommend that products should be routinely inspected by customers to ensure they perform as expected.
For products without retest or expiration dates, our standard warranty of 1 year from the date of shipment is applicable.
For more information, please refer to the Product Dating Information document: https://www.sigmaaldrich.com/deepweb/assets/sigmaaldrich/marketing/global/documents/418/501/product-dating-information-06-25-mk.pdf
1.06076
Methyl red (C.I. 13020)
pH indicator, ACS, Reag. Ph Eur
Synonym(s):
Methyl red (C.I. 13020), 4-Dimethylaminoazobenzene-2′-carboxylic acid
Select a Size
| Size/SKU | Availability | Price |
|---|---|---|
25 g | Estimated to ship onDecember 29, 2026 | $65.90 |
100 g | Estimated to ship onAugust 13, 2027 | $231.00 |
About This Item
Product Name
Methyl red (C.I. 13020), indicator ACS,Reag. Ph Eur
grade
ACS reagent
Quality Segment
agency
reag. Ph. Eur., suitable for SM 4500 - NH3
form
powder, solid
loss
≤5% loss on drying, 110°C
color
red to red-violet
visual transition interval
4.4-6.0, red to yellow
mp
178-182 °C
bulk density
300‑500 kg/m3
Amax
427-437 nm (buffer pH 6.2), 523-526 nm (buffer pH 4.5)
storage temp.
2-30°C
SMILES string
N(C)(C)c1ccc(cc1)N=Nc2c(cccc2)C(=O)O
InChI
1S/C15H15N3O2/c1-18(2)12-9-7-11(8-10-12)16-17-14-6-4-3-5-13(14)15(19)20/h3-10H,1-2H3,(H,19,20)
InChI key
CEQFOVLGLXCDCX-UHFFFAOYSA-N
Analysis Note
Appearance: Red to red-violet powder, eventually with granular parts.
Clarity of solution (1 g/l; ethanol): passes test
Melting point (capillary method, temperatur measerment in the heating block): 179 - 182 °C
Transition range: pH 4.4 - pH 6.0 Red - yellow
Absorption maximum (buffer pH 4.5): 523 - 526 nm
Absorption maximum (buffer pH 6.2): 427 - 437 nm
Spec. Absorptivity A 1%/1cm (λmax; 0.005 g/l; buffer pH 4.5; calculated on anhydrous substance): 1350 - 1500
Spec. Absorptivity A 1%/1cm (λmax; 0.005 g/l; buffer pH 6.2; calculated on anhydrous substance): 700 - 800
Transition range (according to ACS): passes test
Loss on drying (110 °C): ≤ 5 %
1 of 1
This Item | |||
|---|---|---|---|
| description indicator ACS,Reag. Ph Eur | description pH 4.2-6.2 | description suitable for microbiology | description water-soluble ACS |
| visual transition interval 4.4-6.0, red to yellow | visual transition interval - | visual transition interval - | visual transition interval - |
| bulk density 300‑500 kg/m3 | bulk density - | bulk density - | bulk density 360 kg/m3 |
| mp 178-182 °C | mp - | mp - | mp - |
| grade ACS reagent | grade - | grade - | grade ACS reagent |
| loss ≤5% loss on drying, 110°C | loss - | loss - | loss ≤5% loss on drying, 110°C |
| color red to red-violet | color - | color - | color - |
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Storage Class
11 - Combustible Solids
flash_point_f
Not applicable
flash_point_c
Not applicable
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How is shipping temperature determined? And how is it related to the product storage temperature?
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Products may be shipped at a different temperature than the recommended long-term storage temperature. If the product quality is sensitive to short-term exposure to conditions other than the recommended long-term storage, it will be shipped on wet or dry-ice. If the product quality is NOT affected by short-term exposure to conditions other than the recommended long-term storage, it will be shipped at ambient temperature. As shipping routes are configured for minimum transit times, shipping at ambient temperature helps control shipping costs for our customers. For more information, please refer to the Storage and Transport Conditions document: https://www.sigmaaldrich.com/deepweb/assets/sigmaaldrich/marketing/global/documents/316/622/storage-transport-conditions-mk.pdf
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