Dear Ladies and Gentlemen,

I have got an urgent question:
I am working on a study which compares different 
quantification methods for black carbon.
For that study I do need the standard reference material 
NIST SRM 1649a "urban dust" which is not available at the 
NIST at the moment.
Can anybody help me out with about 0.5 g of that stuff??

Thank you!

Philipp Roth
Institute for Crop Science and Recourse Conservation
Department of Soil Science
University of Bonn
Nussallee 13
53113 Bonn