<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">sabine,<div>we have used the EM method to quantify total number of particles using polystyrene beads as an internal standard. you must titer to quantify <i>infective</i> particles, of course. uv method will work fine, but assumes that all of the absorbing species are actually proteins incorporated into a viral particle (i.e., will also detect partially-assembled structures).</div><div>peter - the nanosight sounds interesting ...</div><div>cec<br><div apple-content-edited="true"> <span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Arial; font-size: 16px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; 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-webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; -webkit-text-decorations-in-effect: none; text-indent: 0px; -webkit-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div>=========================================</div><div class="AppleMailSignature" id="E068926E-CBFB-4349-A3D4-4A4D372065CF"><div><font class="Apple-style-span" face="Arial" size="3"><span class="Apple-style-span" style="font-size: 12px; font-family: Arial; "><span class="Apple-style-span" style="font-family: Arial; font-size: 12px; ">Carlos Enrique Catalano, Pharm.D., Ph.D.</span></span></font></div><div><font class="Apple-style-span" face="Arial" size="3"><span class="Apple-style-span" style="font-size: 12px; 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font-family: Arial; "><span class="Apple-style-span" style="font-family: Arial; font-size: 12px; ">Box 357610</span></span></font></div><div><font class="Apple-style-span" face="Arial" size="3"><span class="Apple-style-span" style="font-size: 12px; font-family: Arial; "><span class="Apple-style-span" style="font-family: Arial; font-size: 12px; ">Seattle, WA 98195-7610</span></span></font></div><div><font class="Apple-style-span" face="Arial" size="3"><span class="Apple-style-span" style="font-size: 12px; font-family: Arial; "><span class="Apple-style-span" style="font-family: Arial; font-size: 12px; ">(206) 685-2468 (office)</span></span></font></div><div><font class="Apple-style-span" face="Arial" size="3"><span class="Apple-style-span" style="font-size: 12px; font-family: Arial; "><span class="Apple-style-span" style="font-family: Arial; font-size: 12px; ">(206) 685-3252 (fax)</span></span></font></div><div><font class="Apple-style-span" face="Arial" size="3"><span class="Apple-style-span" style="font-size: 12px; font-family: Arial; "><span class="Apple-style-span" style="font-family: Arial; font-size: 12px; "><a href="mailto:catalanc@u.washington.edu">catalanc@u.washington.edu</a></span></span></font></div><div><font class="Apple-style-span" face="Arial" size="3"><span class="Apple-style-span" style="font-size: 12px; font-family: Arial; "><span class="Apple-style-span" style="font-family: Arial; font-size: 12px; "><a href="http://depts.washington.edu/medchem/faculty/Catalano.html">http://depts.washington.edu/medchem/faculty/Catalano.html</a></span></span></font></div></div></div><br class="Apple-interchange-newline"></span></div></span><br class="Apple-interchange-newline"></div></span><br class="Apple-interchange-newline"></div></span><br class="Apple-interchange-newline"></div></span><br class="Apple-interchange-newline"> </div><br><div><div>On Mar 4, 2010, at 2:57 AM, <a href="mailto:kaltofen@uni-potsdam.de">kaltofen@uni-potsdam.de</a> wrote:</div><br class="Apple-interchange-newline"><div>Dear all,<br><br>we are trying to obtain the concentration of bacteriophages in a solution, concentration meaning the number of particles per ml. The solution is supposed to be monodisperse and the MW is (roughly) known but could be determined exactly. Is the any idea of how to do this with a hydrodynamic method (staining is difficult to compare between phage mutants and counting infected cells is tedious). I`ve got the "feeling" that one could use the number-averaged MW, but maybe this is totally wrong.<br><br>Thank you for any hints, literature is also welcome.<br><br>Cheers,<br><br>Sabine<br><br><br><br><br>Sabine Kaltofen<br>PhD student<br><br>Universität Potsdam<br>Department of Physical Biochemistry<br>Institute of Biochemistry and Biology<br>Karl-Liebknecht-Str. 24-25, Haus 25, Raum B/0.05<br>D-14476 Potsdam-Golm<br>Telefon: +49-(331)-977-5245<br>Email: <a href="mailto:kaltofen@uni-potsdam.de">kaltofen@uni-potsdam.de</a><br><br><br><br>_______________________________________________<br>RASMB mailing list<br><a href="mailto:RASMB@rasmb.bbri.org">RASMB@rasmb.bbri.org</a><br>http://rasmb.bbri.org/cgi-bin/mailman/listinfo/rasmb<br></div></div><br></div></body></html>