Absolutely, pretreatment of the glass capillary with a gaseous phase high contact angle contact modifier. I would suggest either a Perfluourosilane or a FDTS, treatment will render the glass highly hydrophobic and resistant to anything sticking to it. Contact me for further details. bmoffat@yieldengineering.com Bill Moffat -----Original Message----- From: mems-talk-bounces+bmoffat=yieldengineering.com@memsnet.org [mailto:mems-talk-bounces+bmoffat=yieldengineering.com@memsnet.org] On Behalf Of Mohammed Asfer Sent: Wednesday, April 21, 2010 3:40 AM To: mems-talk@memsnet.org Subject: [mems-talk] Pretreatment of the glass capillary Hi all, I need some information on this. I am using Fluorescent Carboxyl Magnetic particles (SPHEROTEC Inc) which will be passed through a Borosilicate glass capillary. Now what I have observed during the flow of the above magnetic particles (dispersed in H20), some of the particles are sticking to the glass surface. So can anyone suggest that any pretreatment of the glass capillary will solve the problem? Regards Asfer