[RASMB] Nanoparticle absorbance question

Henry A Havel havel_henry_a at lilly.com
Wed Jun 13 12:42:32 PDT 2012


Debby,

If the nanoparticles were larger than 26 nm, the sample will scatter light non-uniformly as a function of angle.  (Particles larger than 1/20th wavelength of light cannot be considered Rayleigh scatterers.)  Because the scattered light has angular dependence, the two instruments are "intercepting" the scattered light differently due to different optical designs.  This may explain some of the discrepancy at least.

Here's a reference that also may be useful:  B. Van Eerdenbrugh, D.E. Alonzo, L.S. Taylor, Influence of Particle Size on the UItraviolet Spectrum of Particulate-Containing Solutions, Pharm. Res., DOI 10.1007/s11095-011-0399-4.

Henry A. Havel, Ph.D.
Eli Lilly and Company
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From: rasmb-bounces at rasmb.bbri.org [mailto:rasmb-bounces at rasmb.bbri.org] On Behalf Of Deborah Pheasant
Sent: Wednesday, June 13, 2012 3:10 PM
To: rasmb at server1.bbri.org
Subject: [RASMB] Nanoparticle absorbance question

Hi all,
We had a suspension of nanoparticles (metal oxides) in culture medium with FBS proteins and it measured 0.5 AU at 530 nm in a UV/VIS spec.  When we put it into SV centerpieces, it read that it had an A530 of about -0.1 or -0.2.  We are perplexed as to why this should be.  Have you had similar experiences or do you have an idea about what might be going on?
Thanks very much,
Debby Pheasant
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