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<p class="MsoNormal"><span style="color:#1F497D">Debby,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">If the nanoparticles were larger than 26 nm, the sample will scatter light non-uniformly as a function of angle. (Particles larger than 1/20<sup>th</sup> 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.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">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.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="color:#1F497D">Henry A. Havel, Ph.D.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Eli Lilly and Company<o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> rasmb-bounces@rasmb.bbri.org [mailto:rasmb-bounces@rasmb.bbri.org]
<b>On Behalf Of </b>Deborah Pheasant<br>
<b>Sent:</b> Wednesday, June 13, 2012 3:10 PM<br>
<b>To:</b> rasmb@server1.bbri.org<br>
<b>Subject:</b> [RASMB] Nanoparticle absorbance question<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Hi all,<o:p></o:p></p>
<p class="MsoNormal">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?<o:p></o:p></p>
<p class="MsoNormal">Thanks very much,<o:p></o:p></p>
<p class="MsoNormal">Debby Pheasant<o:p></o:p></p>
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