Fluorescence of dipicolinic acid as a possible component of the observed UV emission spectra of bacterial spores

Raphael Nudelman, Nicole Feay, Mathew Hirsch, Shlomo Efrima, Burt Bronk

Research output: Contribution to journalConference articlepeer-review

7 Scopus citations


Dipicolinic acid (DPA) and the Ca 2+ complex of DPA (CaDPA) are well-known and are major chemical components of bacterial spores. DPA's native fluorescence is very weak and is thought to be completely masked by the fluorescence of tryptophan when this compound is present. Thus fluorescence related to DPA in spores is assumed by many authors to be completely absent. We show that the fluorescence of CaDPA is substantial for excitation between about 290 nm and 310 nm with emission peaking near 400 nm. This emission is at the long wavelength tail for emission from tryptophan. We examine whether the emission of CaDPA could contribute to the total emission spectrum when bacterial spores are present in an aerosol, for excitation wavelengths in the neighborhood of 310 nm. In this report we present measurements of fluorescence excitation and emission for CaDPA and compare them with that of DPA and tryptophan.

Original languageEnglish
Pages (from-to)190-195
Number of pages6
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - 1 Jan 1999
Externally publishedYes
EventProceedings of the 1998 Air Monitoring and Detection of Chemical and Biological Agents - Boston, MA, USA
Duration: 2 Nov 19983 Nov 1998

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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