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Amino-dPEG®₄-t-butyl ester (QBD-10221)



Amino-dPEG®4–t-butyl ester, product number QBD-10221, is a PEG modification reagent consisting of a primary amino group and the tert-butyl ester of a propionic acid group on either end of a monodisperse PEG4 spacer. The terminal amine reacts with carboxylates to form amide bonds and with aldehydes and ketones to form semi-labile, reducible Schiff bases. Trifluoroacetic acid (TFA) effectively removes the tert-butyl ester protecting group, thus freeing the propionic acid for reaction with amines or formation of an active ester with N-hydroxysuccinimide (NHS) or 2,3,5,6-tetrafluorophenol (TFP).


Unit Size100 mg, 1000 mg
Molecular Weight321.41; single compound
Chemical formulaC₁₅H₃₁NO₆
Purity> 98%
SpacersdPEG® Spacer is 16 atoms and 18.0 Å
Typical solubility properties (for additional information contact Customer Support)Methylene chloride, DMAC, or DMSO.
Storage and handling-20°C; Always let come to room temperature before opening; be careful to limit exposure to moisture and restore under an inert atmosphere; stock solutions can be prepared with dry solvent and kept for several days (freeze when not in use). dPEG® pegylation compounds are generally hygroscopic and should be treated as such. This will be less noticeable with liquids, but the solids will become tacky and difficult to manipulate, if care is not taken to minimize air exposure.


  1. Greg T. Hermanson, Bioconjugate Techniques, 3rd Edition, Elsevier, Waltham, MA 02451, 2013, ISBN 978-0-12-382239-0; See Chapter 18, Discrete PEG Reagents, pp. 787-821, for a full overview of the dPEG® products.

  2. The compatibility of hepatocytes with chemically modified porous silicon with reference to in vitro biosensors. Sara D. Alvarez, Austin M. Derfus, Michael P. Schwartz, Sangeeta N. Bhatia, Michael J. Sailor. Biomaterials. 2009, 30(1) pp26-34. September 4, 2008. 10.1016/j.biomaterials.2008.09.005.

  3. Chemical Modification of Silicon Surfaces for Biological Applications. Michael P. Schwartz, Frédérique Cunin, Ronnie W. Cheung, Michael J. Sailor. physica status solidi. 2005, 202 (8) pp 1380-1384. May 23, 2005. 10.1002/pssa.200461106.

Applicable patents and legal notices are available at legal notices.

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