All Photos(1)




Phosphate Buffered Saline with 0.05% TWEEN® 20, pH 7.4

pHast Pack, powder

Sign Into View Organizational & Contract Pricing

PBS + 0.05% TWEEN® 20, PBS with 0.05% Tween 20, PBS-T, PBST

product line

pHast Pack



Looking for similar products? Visit Product Comparison Guide

General description

Phosphate Buffered Saline with 0.05% Tween® 20 or PBST contains PBS buffer with a low-concentration of Tween® detergent. It is a common wash buffer and due to the presence of detergent, it can easily remove or block excess components thus reducing foaming and non-specific binding on the membrane and microtiter plate wells.


PBST is used in research in a variety of assays including DNA or RNA hybridization assays and cell culture. It is commonly used for immunoassays like Western blot, ELISA, Dot blot, Immunohistochemistry (IHC), immunopercipitation (IP), and immunofluorecence. It has been used for incubation and wash buffer for peptide microarrays for performing High-density peptide array (HDPA) to analyze antibody responses against SARS-CoV-2.

Features and Benefits

  • Ready-to-use buffer
  • No measuring and pH adjusting needed
  • Save time and minimize effort
  • Biological tests: free of DNase, RNase, protease, and nickase
  • Chemical tests: Iron ≤10 ppm, lead ≤5 ppm


Foil pouches


Contents of one pouch, when dissolved in 500 mL of distilled or deionized water, will yield a 1× solution containing 10 mM Na2HPO4, 1.8 mM KH2PO4, 138 mM NaCl, 2.7 mM KCl; 0.05% Tween 20 (w/v), pH 7.4 at 25 °C. Certified to be DNAse, RNAse, Protease, and Nickase free.

Storage and Stability

Store at room temperature. Product may naturally agglomerate but can be simply broken up within the pouch prior to use.

Other Notes

For additional information on our range of Biochemicals, please complete this form.

Legal Information

TWEEN is a registered trademark of Croda International PLC
pHast Pack is a trademark of Sigma-Aldrich Co. LLC

Storage Class

11 - Combustible Solids




Not applicable


Not applicable

Certificates of Analysis (COA)

Search for Certificates of Analysis (COA) by entering the products Lot/Batch Number. Lot and Batch Numbers can be found on a product’s label following the words ‘Lot’ or ‘Batch’.

Already Own This Product?

Documents related to the products that you have purchased in the past have been gathered in the Document Library for your convenience.

Visit the Document Library

Difficulty Finding Your Product Or Lot/Batch Number?

Product numbers are combined with Pack Sizes/Quantity when displayed on the website (example: T1503-25G). Please make sure you enter ONLY the product number in the Product Number field (example: T1503).


Product Number
Pack Size/Quantity

Additional examples:





enter as 1.000309185)

Having trouble? Feel free to contact Technical Service for assistance.

Lot and Batch Numbers can be found on a product's label following the words 'Lot' or 'Batch'.

Aldrich Products

  • For a lot number such as TO09019TO, enter it as 09019TO (without the first two letters 'TO').

  • For a lot number with a filling-code such as 05427ES-021, enter it as 05427ES (without the filling-code '-021').

  • For a lot number with a filling-code such as STBB0728K9, enter it as STBB0728 without the filling-code 'K9'.

Not Finding What You Are Looking For?

In some cases, a COA may not be available online. If your search was unable to find the COA you can request one.

Request COA

Our team of scientists has experience in all areas of research including Life Science, Material Science, Chemical Synthesis, Chromatography, Analytical and many others.

Contact Technical Service