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2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt

tablet, 10 mg substrate per tablet

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AzBTS-(NH4)2, Diammonium 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate)
Empirical Formula (Hill Notation):
CAS Number:
Molecular Weight:
EC Number:
MDL number:
PubChem Substance ID:

Quality Level




deionized water: 100 mL

storage temp.

room temp

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powder or crystals



storage temp.

room temp

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General description

ABTS mainly used in ELISA (enzyme-linked immunosorbent assay) procedures.
ABTS, 2,2′-Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid), is a chromogenic substrate used:
  • For a reaction with laccase or bilirubin oxidase
  • For a reaction with peroxidase enzymes: (like HRP for example). ABTS in combination with hydrogen peroxide
A peroxidase reaction of ABTS in the presence of hydrogen peroxide produces a green soluble end product which can be read spectrophotometrically at 405nm. The reaction may be stopped with 1% sodium dodecyl sulfate (SDS).
ABTS, 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt is light sensitive, and water soluble chemical compound


  • 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt, ABTS, has been used as a substrate in ELISA (enzyme-linked immunosorbent assay).†
  • ABTS is also used to measure glucose concentrations in different solutions including blood serum.
  • The food industry uses ABTS to measure the antioxidant capacities within different foods.
  • Since it is less readily oxidized than TMB and OPD substrates, ABTS is less sensitive for ELISA applications. Thus ABTS has some advantageous over TMB and OPD in cases of large background results
  • It is recommended for ELISA (microwell) procedures, not recommended for membrane applications.
2,2′-Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) is a peroxidase substrate suitable for use in ELISA procedures. This substrate produces a soluble end product that is green in color and can be read spectrophotometrically at 405 nm. The reaction may be stopped with 1% sodium dodecyl sulfate (SDS). Recommended for ELISA (microwell) procedures, not recommended for membrane applications.


Dissolve 1 tablet in 100 ml of 0.05 M phosphate-citrate buffer, pH 5.0 (Tablets available as Sigma Product No. P4809). Add 25 μl of fresh 30% hydrogen peroxide

Storage Class Code

11 - Combustible Solids



Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Personal Protective Equipment

dust mask type N95 (US), Eyeshields, Gloves

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Development of a feline proinsulin immunoradiometric assay and a feline proinsulin enzyme-linked immunosorbent assay (ELISA): A novel application to examine beta cell function in cats
Kley S, et al.
Domestic Animal Endocrinology, 311-318 (2008)
Arokia Vijaya Anand Mariadoss et al.
Antioxidants (Basel, Switzerland), 10(1) (2021-01-16)
Traditional, complementary, and integrative medicine are globally accepted alternative methods for the treatment of diabetes mellitus (DM). However, the mechanism of anti-diabetic effects of Helianthus tuberosus L. remains unproven. In the present study, antioxidant and anti-diabetic activity of the tubers
H Gallati
Journal of clinical chemistry and clinical biochemistry. Zeitschrift fur klinische Chemie und klinische Biochemie, 17(1), 1-7 (1979-01-01)
The reaction of the two substrates hydrogen peroxide and ABTS with horseradish peroxidase was studied kinetically. Enzyme activity was determined as a function of substrate concentration and pH. Michaelis constants were determined for the two substrates at various pH values.
B Porstmann et al.
Journal of clinical chemistry and clinical biochemistry. Zeitschrift fur klinische Chemie und klinische Biochemie, 19(7), 435-439 (1981-07-01)
o-Phenylenediamine, 2,2'-azino-di(3-ethylbenzthiazoline sulphonic acid-6) (ABTS), o-dianisidine and 4-aminoantipyrine were compared as chromogens for the determination of horseradish peroxidase. Highest sensitivity in the determination of horseradish peroxidase-IgG conjugates in dissolved form was obtained with o-phenylenediamine. When these conjugates were used in
Vignesh Narayanaswamy et al.
Breastfeeding medicine : the official journal of the Academy of Breastfeeding Medicine, 16(12), 987-994 (2021-08-13)
Objective: To evaluate the immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in colostrum from women who tested positive for the virus. Methods: Between March and September 2020 we obtained bilateral colostrum samples collected on spot cards within


Nitroblue Tetrazolium (NBT) is used with the alkaline phosphatase substrate 5-Bromo- 4-Chloro-3-Indolyl Phosphate (BCIP) in western blotting and immunohistological staining procedures. These substrate systems produce an insoluble NBT diformazan end product that is blue to purple in color and can be observed visually.


To measure alcohol oxidase activity, this assay uses 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) and a continuous spectrophotometric rate determination at 405 nm.

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