• Product name
    100x Citrate Buffer pH 6.0
    See all Citrate buffer reagents
  • Tested applications
    Suitable for: IHC-Pmore details
  • General notes

    Citrate buffer pH 6.0 for heat-induced antigen retrieval (HIER) during IHC (ab64236).


  • Form
  • Storage instructions
    Store at room temperature.
  • Storage buffer
    pH: 6.00
    Constituent: 1% Hydrochloric acid
    Note: Buffer 100X concentrated.
  • Concentration information loading...
  • Research areas
  • Relevance
    Citrate buffer is used on formalin-fixed, paraffin-embedded tissue sections mounted on glass slides for target retrieval prior to immunohistochemistry (IHC) procedures. Target retrieval prior to IHC procedures obtains positive results, or results in an increase in staining intensity with many primary antibodies.


Our Abpromise guarantee covers the use of ab64236 in the following tested applications.

The application notes include recommended starting dilutions; optimal dilutions/concentrations should be determined by the end user.

Application Abreviews Notes
IHC-P Use at an assay dependent dilution.


  • Immunohistochemical analysis of liver tissue section labeling PCNA with ab18197 at 1/250. Antigen retrieval was performed with antigen retrieval buffer, ab64236. A and B, PCNA staining in right and left grafts 1 day after reperfusion. E and F, PCNA staining in right and left grafts 5 day after reperfusion.




  • Immunohistochemical analysis of mouse lung. Samples were fixed in 10% buffered formalin, paraffinized and sliced at 1.5 µm thick. Antigen retrieval was performed using ab64214 for the deparaffinized slices. Sections were blocked with 2% normal goat serum, PBS(-) and 0.1% Tween20. They were then incubated with the primary antibodies for 1 hour at 4°C and with secondary antibodies for 30 minutes at room temperature. The avidin-biotin-peroxidase complex method with peroxidase streptavidin and the DAB substrate kit ab64238 was performed.

    (A) A resected lung from a mouse sacrificed 28 days after SCL injection.

    (B) Haemotoxylin and Eosin staining showing the tumor composed of a central area with necrosis and a peripheral zone filled with SCLs.

    (C) Immunohistochemical staining for MMP-14 showing positive expression of MMP-14 in the peripheral zone of the tumor and negative in central zone.

    (D) Immunohistochemical staining weak staining of MMP-2 in the peripheral zone.

    This image was produced using ab64214 (a lower concentration of ab64236 ). Therefore, we expect ab64236 to work as well when diluted to the required concentration. 


This product has been referenced in:
  • Sotnichenko AS  et al. Morphological Evaluation of the Tissue Reaction to Subcutaneous Implantation of Decellularized Matrices. Bull Exp Biol Med 166:287-292 (2018). Read more (PubMed: 30488196) »
  • Celebi AR  et al. Evaluation of the 'Hedgehog' signaling pathways in squamous and basal cell carcinomas of the eyelids and conjunctiva. Oncol Lett 12:467-472 (2016). Read more (PubMed: 27347166) »
See all 5 Publications for this product

Customer reviews and Q&As

1-2 of 2 Abreviews or Q&A


Thank you very much for contacting us.

I have received a reply from a colleague who run the test in lab, for checking the change in pH when this product is diluted. They have confirmed that, with the dilution there was only a fraction of change in pH which was ˜0.4 from 7.98 to 7.56.

We are convinced that product we have sent is of high quality. There should not be a change in pH when diluted. Please check the diluents you have been using or retest the pH.

I would suggest using the product in Immunohistochemistry as recommended; this will work. In any case if this product does not work please contact me we will replace the product.

I hope this information will be helpful. Should you have any other question please do not hesitate to ask.

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Thank you for contacting us.

The basic protocol for using a microwave with this buffer is as follows:

1. Deparaffinize and rehydrate tissue sections.
2. Dilute the product 1:100 with deionized water. Example: 2 ml of concentrate diluted in 198 ml of deionized water.
3. Immerse sections in Coplin jar filled with diluted Citrate Buffer reagent..
4. Microwave on HIGH power until boiling.
5. Keep the slides warm by heating for 10 minutes on LOW power.
6. Let Coplin jar sit in microwave for at least 20 minutes.
7. Remove and rinse with water..
8. Rinse with buffer and proceed with the appropriate staining protocol for the primary antibody in use.

You can subsitute any plastic rack and container for the Coplin jar. The main thing to avoid is allowing the sections to dry out, so make sure the sections are completely covered by the buffer at all times during and after the hot incubation.

You may want to test heating the buffer in the container without any slides, as it is very easy for the buffer to boil over (that is, to boil too much and too vigorously) so that some of the buffer is lost, exposing the sections to air. If using the microwave, it is important to control the boiling by using low power and watching the solution as it incubates, if necessary.

To avoid the boiling over that can occur in a microwave, a waterbath can be substituted for the microwave by simply heating the waterbath to 95-100oC and placing the container with the rack of slides and pre-heated buffer (or the Coplin jar with pre-heated buffer) in the hot waterbath for 15 - 20 minutes. The amount of time in the microwave or waterbath may need to be optimized but 15 - 20 minutes is usually sufficient, followed by 20 minutes to allow the buffer to cool, with the slides still in the container or Coplin jar.

I hope this information is helpful to you. Please do not hesitate to contact us if you need any more advice or information.

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