Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Separation of 2 : 4 Dinitrophenyl Amino-acids on Buffered Silica Gel


FOR some time past I have been making a study of the free amino groups of the peptides liberated by papain and sodium bisulphite acting on wool keratin1, using Sanger's methods2,3. At an early stage it was found that 'non-absorbent gels' which were of service in separating N-acetyl amino-acids were of little use in separating 2 : 4 dinitrophenylamino-acids, which all ran together as a single fast band using chloroform as solvent. Phillips and Stephen4 and Consden, Gordon, Martin and Synge5 have previously commented on the difficulty of preparing suitable gels with reproducible properties. Sanger2 and Consden et al.5 considered that silica gels which permitted satisfactory separations 'absorbed' the dinitrophenyl amino-acids to some extent. I have observed that successful separations of these acids on silica gel can be achieved by using concentrated phosphate buffers instead of water as the stationary phase; by varying the pH of the buffer, the rate of movement of the band of a particular acid can be varied within wide limits, the higher the pH the slower being the rate.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Similar content being viewed by others


  1. Middlebrook, W. R., and Phillips, H., J. Soc. Dyers and Col., 57, 137 (1941).

    Article  CAS  Google Scholar 

  2. Sanger, F., Biochem. J., 39, 507 (1945).

    Article  CAS  Google Scholar 

  3. Porter, R. R., and Sanger, F., Biochem. J., 42, 287 (1948).

    Article  CAS  Google Scholar 

  4. Phillips, D. M. P., and Stephen, J. M. L., Nature, 162, 152 (1948).

    Article  ADS  CAS  Google Scholar 

  5. Consden, R., Gordon, A. H., Martin, A. J. P., and Synge, R. L. M., Biochem. J., 41, 596 (1947).

    Article  CAS  Google Scholar 

  6. Moyle, V., Baldwin, E., and Scarisbrick, R., Biochem. J., 43, 308 (1948).

    Article  CAS  Google Scholar 

  7. Levi, A. A., Biochem. J., 43, 257 (1948).

    Article  CAS  Google Scholar 

  8. Boon, W. R., Calam, C. T., Gudgeon, H., and Levi, A. A., Biochem. J., 43, 262 (1948).

    Article  CAS  Google Scholar 

Download references

Author information

Authors and Affiliations


Rights and permissions

Reprints and permissions

About this article

Cite this article

BLACKBURN, S. Separation of 2 : 4 Dinitrophenyl Amino-acids on Buffered Silica Gel. Nature 163, 955–956 (1949).

Download citation

  • Issue Date:

  • DOI:

This article is cited by


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing