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  • 32670 - 4′,6-Diamidino-2-phenylindole dihydrochloride

32670 Sigma-Aldrich

4′,6-Diamidino-2-phenylindole dihydrochloride

BioReagent, suitable for fluorescence, ≥95.0% (HPLC)

Synonym: 2-(4-Amidinophenyl)-6-indolecarbamidine dihydrochloride, DAPI dihydrochloride

  • CAS Number 28718-90-3

  • Empirical Formula (Hill Notation) C16H15N5 · 2HCl

  • Molecular Weight 350.25

  •  Beilstein/REAXYS Number 4894417

  •  EC Number 249-186-7

  •  MDL number MFCD00012681

  •  PubChem Substance ID 57648699

  •  NACRES NA.32



Related Categories Biochemicals and Reagents, Detection, Fluorescent Enzyme Substrates, Fluorescent Enzyme Substrates for Electrophoresis, Fluorescent Probes, Labels, Particles and Stains,
Quality Level   100
product line   BioReagent
assay   ≥95.0% (HPLC)
solubility   DMF: soluble
  H2O: soluble
fluorescence   λex 340 nm; λem 488 nm (nur DAPI)
  λex 364 nm; λem 454 nm (DAPI-DNA-Komplex)
  λex 374 nm; λem 461 nm in 10 mM Tris; 1 mM EDTA; pH 8.0; DNA
suitability   suitable for fluorescence
SMILES string   Cl.Cl.NC(=N)c1ccc(cc1)-c2cc3ccc(cc3[nH]2)C(N)=N
InChI   1S/C16H15N5.2ClH/c17-15(18)10-3-1-9(2-4-10)13-7-11-5-6-12(16(19)20)8-14(11)21-13;;/h1-8,21H,(H3,17,18)(H3,19,20);2*1H



DAPI is several times more sensitive than ethidium bromide for staining DNA in agarose gels. It may be used for photofootprinting of DNA, to detect annealed probes in blotting applications by specifically visualizing the double-stranded complex, and to study the changes in DNA and analyze DNA content during apoptosis using flow cytometry. DAPI staining has also been shown to be a sensitive and specific detection method for mycoplasma.

Biochem/physiol Actions

Cell permeable fluorescent minor groove-binding probe for DNA. Binds to the minor groove of double-stranded DNA (preferentially to AT rich DNA), forming a stable complex which fluoresces approximately 20 times greater than DAPI alone.


Bottomless glass bottle. Contents are inside inserted fused cone.

Safety & Documentation

Safety Information

GHS07  GHS07
Signal word 
Hazard statements 
Target organs 
Respiratory system
Personal Protective Equipment 
NONH for all modes of transport
WGK Germany 
Flash Point(F) 
Not applicable
Flash Point(C) 
Not applicable


Certificate of Analysis (COA)

Please Enter a Lot Number

Frequently Asked Questions

Which document(s) contains shelf-life or expiration date information for a given product?
If available for a given product, the recommended re-test date or the expiration date can be found on the Certificate of Analysis.
How do I get lot-specific information or a Certificate of Analysis?
The lot specific COA document can be found by entering the lot number above under the "Documents" section.
How can I make a solution of 4´,6-Diamidino-2-phenylindole dihydrochloride (DAPI), Product 32670?
DAPI is soluble in water (10mg/mL) with heat or sonication as necessary. It is insoluble in PBS even at 1 mg/ml.
How can I store solutions of 4´,6-Diamidino-2-phenylindole dihydrochloride (DAPI), Product 32670?
At 1 mg/mL, the solutions are stable in the dark at 2-8 °C for several weeks. For long-term storage, the solutions can be divided into aliquots and stored frozen at -20°C
What concentration of4´,6-Diamidino-2-phenylindole dihydrochloride (DAPI), Product 32670, is used to as a nuclear counterstain for tissue sections?
Following fluorescent staining of the cells, DAPI is added to the mounting media at 2 μg/ml.
What concentration of4´,6-Diamidino-2-phenylindole dihydrochloride (DAPI), Product 32670, is used to as a nuclear stain for cultured cells?
Use DAPI at 0.1 microgram per mL in phosphate buffered saline (PBS) to incubate with monolayer cultured cells for 15-30 minutes at 30°C.Immediately examine with a fluorescence microscope.
How do I find price and availability?
There are several ways to find pricing and availability for our products. Once you log onto our website, you will find the price and availability displayed on the product detail page. You can contact any of our Customer Sales and Service offices to receive a quote. USA customers: 1-800-325-3010 or view local office numbers.
What is the Department of Transportation shipping information for this product?
Transportation information can be found in Section 14 of the product's (M)SDS.To access the shipping information for this material, use the link on the product detail page for the product.
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