Thiol Quantification Assay Kit (Fluorometric) (ab112158)


  • Product name
    Thiol Quantification Assay Kit (Fluorometric)
    See all Thiol kits
  • Sample type
    Urine, Plasma, Cell culture extracts
  • Assay type
  • Product overview

    Thiol Quantification Assay Kit (Fluorometric) (ab112158) provides an ultrasensitive fluorometric assay to quantitate thiol content that exists in small molecules such as free cysteine, glutathione, and cysteine residues. The assay is based on a proprietary non-fluorescent dye tha generates a strongly fluorescent adduct upon reacting with a thiol compound. The signal produced by the adduct can ebe asily read by a fluorescence microplate reader at Ex/Em = 490/520 nm. In addition, both absorption and emission spectra of the thiol adduct are pH-independent, making the assay highly robust. There are few reagents or assay kits available for quantitating thiol content in biological systems, and the majority of commercial kits either lack sensitivity or have tedious protocols. The assay can detect as little as 1 picomole of cysteine or GSH in a 100 µL assay volume (10 nM). 

    Please note it is not possible to do a quantification in comparison to the standard.

    Visit our FAQs page for tips and troubleshooting.

  • Notes

    This product detects thiol groups on small molecules. If you want to detect thiol groups in proteins, we recommend Total Protein Thiol Quantification Assay Kit (Colorimetric) (ab219272).



  • Standard curve: mean of duplicates (+/- SD) with background reads subtracted

  • GSH measured in cell lysates showing quantity (nmol) per 1 mln cells.

    Samples with the concentration of 1e8 cells/mL were used. Samples were diluted 100-1000 fold.

  • GSH measured in biological fluids. Samples were diluted 10-1000 fold.

  • GSH and Cysteine dose responses were measured in a 96-well black plate with ab112158 using a microplate reader. As low as 10 nM (1 pmol/well) of GSH or Cysteine can be detected with 10 minutes incubation time (n=3). The insert shows the low levels of thiol detection.



ab112158 has not yet been referenced specifically in any publications.

Customer reviews and Q&As

1. The kit can only quantify thiol groups, not disulfide bonds.

2. DTT cannot be used as reducing agent because it contains -SH groups, and these will interfere with this assay. That is also the case for beta mercaptoethanol. If either has t...

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This kit is very sensitive to presence of DTT, beta mercaptoethanol or guanidine HCl. Even nanomolar quantities of these reagents will negatively effect the results. Please ensure your samples are free of these reagents before using this kit.

The Thiol Quantification Assay Kit (Fluorometric) (ab112158) should be compatible with both Urea or Guanidinium-HCl and should not interfere with the assay.

The kit is provided with glutathione (GSH) as a standard. This molecule contains ...

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Thank you for your email and your interest in our products.

I can confirm that regrettably TCEP and all other reducing agents such as DTTor b-mercaptoethanol will interfere with the Thiol Quantification Assay Kit (Fluorometric) (ab112158).
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Thank you for contacting us.

I have heard back from the lab with the following advice:

A solid black microplate (black walls and black bottom) would bepreferably recommendedover a black-walled microplate with this assay.
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the kit is very easy to use. it contains very low amount of assays though.

Mrs. Smadar Tabenkin

Verified customer

Submitted Sep 03 2014

I can confirm that using bacterial samples should be ok as long as the bacteria is lysed. The detection limit of the kit is 10 nM, so as long as the there is 10 nM cysteine differences among the mutations, it should be OK. Please note this has not bee...

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Thank you for contacting us.

Yes, the kit can be used for endpoint read. I recommend you read at 15min, 30 min and 1 hour see which one is best for your experiment. The Ex/Em=490/520 nm.

I hope this information is helpful to you...

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Please see my math below calculating the minimum volume of your sample needed if we assume the final molar concentration of free cysteine is 25% of the molar concentration of cysteine originally in your sample (50% from 1:1 reduction in DTT or TSEP, th...

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Theoretically TCEP should not effect this assay but it does react with the dye. TCEP seems to react with a lot of the things but unfortunately we are not sure how this occurs.

1-10 of 17 Abreviews or Q&A


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