'total loss' vrees ik ... ;-) -------- Original Message -------- Subject: density Date: Fri, 11 Jun 2010 12:15:49 +0200 From: Stephane Rombauts <strom@psb.vib-ugent.be> To: research@psb.ugent.be Dear all, I'm looking for away to measure the density of a biopolymer lighter than 0.00001g. I could of course collect enough of this polymer to get a mass > 0.0001g, and submerge it then in water to measure the volume via water displacement... But then I would need a LOT of material. And given it is not necessarily easy to get the pure material in large quantities, any other way would be welcome. One option could be a CsCl column and centrifuge it with the biopolymer as was done some time ago to purify DNA (isopycnic centrifugation <http://en.wikipedia.org/wiki/Isopycnic_centrifugation>). The problem there is that I have no way of labeling the polymer to be able to see where in the column the polymer ends up and as I will need a density ladder, the measurement will remain approximative. Alternatively, if you know a (UGent/VIB) department that has a machine that does it all and is sensitive enough, let me know. best regards Stephane -- ============================================================== Lieven Sterck, PhD Tel:+32 (0)9 3313821 Fax:+32 (0)9 3313809 VIB Department of Plant Systems Biology, UGent Bioinformatics and Evolutionary Genomics Division Technologiepark 927, B-9052 Gent, Belgium Email: lieven.sterck@psb.vib-ugent.be Website: http://bioinformatics.psb.ugent.be ============================================================== "You tried your best and you failed miserably. The lesson is: never try!" - H. Simpson