• Assay Type Detection Kit
  • Sample Types Buffers
  • Sensitivity 4.62 nM
  • Assay Duration 30 Minutes
  • Samples/Plate 39 in Duplicate
  • Readout Fluorescent, 510 nm emission / 370-410 nm excitation
  • Standard Curve
  • Description

    Assay Principle: 

    The Thiol Fluorescent Detection Kit quantitatively measures free Thiol levels in buffers. The Thiol Fluorescent Detection Kit is a Detection Kit with a run time of 30 minutes. Please read the complete kit insert for more information before performing this assay.

    Use our provided N-Acetylcysteine standard to generate a standard curve for the assay. Pipette the standards or diluted samples into a black microtiter plate. Add ThioStar® Detection Reagent to each well tapping the plate to ensure sufficient mixing of reagents. Then incubate the mixture covered at room temperature for 30 minutes. The fluorescent reaction occurs between the ThioStar® Detection Reagent and the free Thiol within the sample or standard. 

    After the 30-minute incubation, use a plate reader to detect and record the generated fluorescent signal. Use the intensity and the standard curve to calculate the free Thiol concentration in the samples.


    Free thiols in biological systems have important roles. Oxidatively-modified thiol groups of cysteine residues are known to modulate the activity of many proteins. As such, it is essential to accurately determine the extent of modification of specific amino acids, such as cysteine residues. Detecting this modification is especially difficult in a complex protein sample, especially in the presence of chaotropic agents such as guanidine hydrochloride. Typical methods using Ellman’s reagent do not have sufficient sensitivity to detect free SH groups effectively.

  • Structure Thiol