Synonym(s):

ABTS^™ Chromophore, Diammonium Salt, 2,2ʹ-Azino-bis(3-ethylbenzthiazoline-6-sulfonic Acid), 2NH₄

Description

ABTS, 2,2′-Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid), is water soluble chemical compound used as chromogenic substrate:

ABTS together with hydrogen peroxide for reaction with peroxidase enzymes (like HRP for example).
ABTS together with laccase or bilirubin oxidase.

ABTS mainly used in ELISA (enzyme-linked immunosorbent assay) procedures.
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.

Specifications

Grade	Ultra Pure
Formula	C₁₈H₂₄N₆O₆S₄
MW	548.70
CAS	30931-67-0
1H-NMR Spectrum	Corresponds to assigned structure
13 C-NMR Spectrum	Corresponds to assigned structure
Purity	≥98.0 area-%
Storage	2-8℃

Application

2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) is a widely used peroxidase substrate for HRP-based assays, particularly suitable for ELISA (microwell) procedures. In the presence of hydrogen peroxide and horseradish peroxidase (HRP), ABTS is oxidized to form a soluble green-colored product that can be measured spectrophotometrically at 405 nm. The reaction can be conveniently stopped by adding 1% SDS.

In quantitative HRP-based calibration and kinetic assays, the oxidation state of ABTS prior to use is a critical factor, as even minor pre-oxidation may introduce baseline shifts and affect assay reproducibility. For this reason, ABTS is often preferred in applications where low background and high baseline stability are required.

Compared with TMB and OPD, ABTS is less readily oxidized and therefore less sensitive, but it offers important advantages in cases where high background signals or baseline drift must be minimized, making it well suited for:

Quantitative ELISA calibration curves
HRP kinetic assays requiring stable baselines
Antioxidant capacity measurements in food and biological samples
Monitoring glucose concentrations in serum and solution-based assays

ABTS is not recommended for membrane-based applications.

Biofargo pays particular attention to lot-to-lot consistency and the oxidation state of ABTS, as pre-oxidation may impact baseline signals in quantitative HRP-based assays. For users with strict calibration requirements, we are happy to provide lot-specific evaluation samples or work with customers to establish practical acceptance criteria and long-term lot consistency.

Documents

INFO

COA

SDS

ABTS, Diammonium Salt