8-Anilino-1-naphthalenesulfonic acid ammonium salt

for fluorescence, ≥97.0% (HPLC)

Ammonium 8-anilino-1-naphthalenesulfonate, N-Phenyl peri acid, 1,8-ANS NH4, ANSA
Linear Formula:
C16H13NO3S · NH3
CAS Number:
Molecular Weight:
Beilstein/REAXYS Number:
EC Number:
MDL number:
PubChem Substance ID:
Pricing and availability is not currently available.

Quality Level


for fluorescence


≥97.0% (HPLC)


≤2.5% loss on drying


245-253 °C


H2O: 0.1 g/5mL, clear to very slightly hazy (hot)
NaOH: 1 N
H2O: soluble
acetone: soluble
methanol: soluble


λex 388 nm; λem 470 nm in 0.1 M Tris, 0.2 M KCl, pH 9.0, BSA

SMILES string




InChI key


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This product is an amphiphilic fluorescent probe for protein studies . Excitation of the unbound dye at 380 nm results in a low fluorescent emission with a maximum at 545 nm. The fluorescence intensity of ANS increases when the dye binds to the hydrophobic regions of a protein . The protein-ANS complex has an emission spectrum which is shifted to a broad maximum at 470 nm. At pH 8, protein causes a 40-fold increase in the relative quantum yield compared to free ANS in solution . ANS has been used to monitor protein conformational changes by binding to the hydrophobic regions of a protein , to gain new insight into protein binding interactions, often by acting as reporter or competitor ligands, to investigate the visual excitation process and structural aspects of photoreceptor cell membranes , and to probe (and disrupt) the structure of both high- and low-density lipoproteins. It has also been used as a substrate in a chemiluminescent enzyme immunoassay system and as a dye for yeast viability determination. The conformational states for apo- and holo- yeast alcohol dehydrogenase were reported under conditions of low pH using ANS fluorescence . ANS is also commonly used as a fluorescence probe to investigate molecular assemblies of surfactants and amphiphilic polymers because a blue shift of its emission maximum indicates the probe is located in less polar environment
ANS forms an inclusion complex with cyclodextrin. Such model systems are useful to mimic biological recognition and can be studied by measuring the change in fluorescence of free-ANS to complexed-ANS. When ANS enters the hydrophobic core of cyclodestrin, it′s fluorescence increases . Utilized in the reagent phase of a sodium-selective fiber-optic sensor. The reagent phase also contains a copper(II) polyelectrolyte, which binds to ANSA in the absence of sodium and quenches the fluorescence. In the presence of sodium, ANSA forms a cationic complex creating ion-pairs, causing it to fluoresce . ANS is often incorporated into di-block polymers and can be released by changes in the local environment (i.e., temperature, pH, etc.) . ANS is commonly used as a fluorescence probe to investigate molecular assemblies of surfactants and amphiphilic polymers because a blue shift of the emission maximum indicates the fluorophore is located in less polar media . Fluorescent probe for protein studies using methodologies such as steady-state and dynamic fluorescence measurements .

Personal Protective Equipment

dust mask type N95 (US),Eyeshields,Gloves


NONH for all modes of transport

WGK Germany


Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Certificate of Analysis
Certificate of Origin
L D'Alfonso et al.
Biochimica et biophysica acta, 1432(2), 194-202 (1999-07-17)
Steady-state and dynamic fluorescence titrations show that: (a) the complex between beta-lactoglobulin (BLG) and 1-anilinonaphthalene-8-sulfonate (ANS) displays a heterogeneous equilibrium with large changes in the binding strength vs. pH and ion concentration; and (b) the fluorescence response of bound ANS...
Maddalena Collini et al.
Protein science : a publication of the Protein Society, 12(8), 1596-1603 (2003-07-24)
The use of spectroscopy in the study of fatty acids binding to bovine beta-lactoglobulin (BLG) appears to be a difficult task, as these acid compounds, assumed as the protein natural ligands, do not exhibit favorable optical response such as, for...
The use of fluorescent probes for the study of membranes.
A Azzi
Methods in enzymology, 32, 234-246 (1974-01-01)
W P Le et al.
Journal of biochemistry, 119(4), 674-679 (1996-04-01)
Under conditions of low pH, the conformational states of holo-YADH and apo-YADH were examined by protein intrinsic fluorescence, ANS fluorescence, and far-UV CD measurements. The results obtained show that a low ionic strength, with the addition of HCl, the holo-...
Oktay K Gasymov et al.
Biochemistry, 47(5), 1414-1424 (2008-01-09)
Human tear lipocalin (TL) exhibits diverse functions, most of which are linked to ligand binding. To map the binding site of TL for some amphiphilic ligands, we capitalized on the hydrophobic and hydrophilic properties of 8-anilino-1-naphthalenesulfonic acid (ANS). In single...
Nitric oxide (NO) as a signal transporter in neurons, endothelial cells and in the immune system.
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